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1.	Lundberg, Daniel, et al. (author) The Chemical Side of SLU : Book of Abstracts 2011 Other publication (other academic/artistic)
2.	Maurina Morais, Eduardo, 1989, et al. (author) Solvent-free synthesis of protic ionic liquids. Synthesis, characterization and computational studies of triazolium based ionic liquids 2022 In: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 360 Journal article (peer-reviewed)abstract A series of triazolium and imidazolium based protic ionic liquids were synthesized using a solvent-free method designed to address several limitations encountered with other commonly used methods. Using this method, pure (98–99% m/m) and dry (128–553 ppm of water) protic ionic liquids were synthesized (in a laboratory scale) without the need for purification methods that require heating the ionic liquid, hence avoiding the common issue of thermal decomposition. This method was also designed to allow for the accurate measurement of acid and base, and for the controlled mixing of both compounds, which is essential to avoid producing impure protic ionic liquids with excess of either acid or base. The system is constructed of only glass and chemically resistant polymer (PTFE and PVDF) parts, which avoid other contaminants that can result from unwanted reactions involving the reagents with common laboratory tools (metallic objects, paper, plastic, etc.). This process is described in detail in the paper as well as in a video. The resulting ionic liquids were carefully analyzed by spectroscopic and thermal methods designed to avoid water absorption, which is known to affect their properties. To complement this experimental characterization, computational chemistry tools were used to assess the ionic liquids’ properties, as well as to assign vibrational modes.
3.	Sauer, Christopher, 1993 (author) Green Aromatics: Catalytic Valorisation of bio-derived 2,5-dimethylfuran over Zeolites and Zeotypes 2022 Doctoral thesis (other academic/artistic)abstract This thesis discusses the use of biomass as a potentially green feedstock for the chemical industry in the urgent shift away from fossil resources. I elaborate on reasons why we cannot afford to burn virgin biomass for energy production, among them a variety of ecosystem services that forests and other lands provide. In addition, the utilisation of biomass should be focused on products that sequester and lock away carbon for more extended periods, e.g. timber, materials and chemicals. In particular, biomass can be used as an alternative "carbon neutral" feedstock for the chemical industry, where we can preserve the already existing chemical complexity in the bio-based molecules. One example is the upgrading of furans to benzene, toluene and xylene (BTX) aromatics with the help of zeolite catalysis. These aromatics are important commodity chemicals, where the shift to a bio-based resource could make use of already existing knowledge, catalyst and production infrastructure. However, research is necessary to understand these new feedstock molecules and their interaction with the catalysts and to enable the design of applicable catalysts. In order to study the interaction of the furans, in particular 2,5-dimethylfuran (2,5-dmf), I describe and discuss the development of an analytical methodology that utilises infrared spectroscopy and mass spectrometry for the on-line identification and quantification of product molecules during catalytic reactions. This on-line analysis method is then applied to the catalytic conversion of 2,5-dmf to aromatics over a range of zeolite and zeotype catalysts. In-depth studies with ammonia as a probe molecule of the catalytic active acid sites, as well as temperature programmed experiments with ammonia and 2,5-dmf give insights into product distribution, selectivity changes and deactivation of the catalyst. For example, olefins and aromatics are initially preferred products, while with increasing time on stream, the isomerisation of 2,5-dmf becomes dominant. The incorporation of Ga into the zeotype framework, resulting in a Ga-Silicate, shows how targeted catalyst design can increase overall aromatics production. This catalyst is also suitable for selective isomerisation of 2,5-dmf to 2,4-dimethylfuran, which has a rare substitution pattern. Finally, itwas found that the most valuable of BTX, p -xylene, can be produced more selectively when 2,5-dmf is pre-adsorbed onto zeolite ZSM-5 and then released during a temperature programmed product desorption.
4.	Maurina Morais, Eduardo, 1989 (author) Synthesis of protic ionic liquids. Challenges and solutions for the synthesis of pure compounds. 2022 Licentiate thesis (other academic/artistic)abstract The urgent need to diversify our energy matrix is responsible for a renewed interest in fuel cell technology, which can use hydrogen gas, a renewable green fuel, as an energy source. This technology is currently a commercially available option, however, it still requires technological improvements before it can be widely used for different applications. One way this technology could potentially be improved is by increasing its temperature range of operation by developing new, anhydrous proton conducting materials. Protic ionic liquids, which are organic salts with low melting temperatures, are interesting candidates for this application, since they can conduct protons in the operational conditions of fuel cells and without the need of water. These compounds can be synthesized by a simple acid-base neutralization reaction, but certain considerations must be taken in order to obtain high quality (dry and pure) protic ionic liquids. In this thesis, a series of triazolium and imidazolium based protic ionic liquids were synthesized using a solvent-free method designed to address several limitations encountered with other commonly used methods. Using this method, pure (98-99% m/m) and dry (128-553 ppm of water) protic ionic liquids were synthesized (in a laboratory scale) without the need for purification methods that require heating the ionic liquid, hence avoiding the common issue of thermal decomposition. This method was also designed to allow for the accurate measurement of acid and base, and for the controlled mixing of both compounds, which is essential to avoid producing impure protic ionic liquids with excess of either acid or base. The system is consists of only glass and chemically resistant polymer(PTFE and PVDF) parts, which avoids other contaminants that can result from unwanted reactions involving the reagents with common laboratory tools (metallic objects, paper, plastic, etc.). The resulting ionic liquids were carefully analyzed by spectroscopic and thermal analysis methods designed to avoid water absorption, which is known to affect their properties. To complement this experimental characterization, computational chemistry tools were used to assess the ionic liquids’ properties, as well as to assign vibrational modes.
5.	Swerin, Agne, et al. (author) Formulation of superhydrophobic pigment coatings 2015 In: Formulation of superhydrophobic pigment coatings. - : TAPPI Press. - 9781510818873 ; , s. 1410-1424 Conference paper (peer-reviewed)
6.	Börjesson, Karl, 1982, et al. (author) Conjugated anthracene dendrimers with monomer-like fluorescence 2014 In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:38, s. 19846-19850 Journal article (peer-reviewed)abstract Two generations of highly emissive conjugated anthracene dendrimers containing up to 9 anthracene units are presented. In these dendrimers, anthracene-like absorption and emission properties are preserved due to the relatively weak electronic coupling between the anthracene units, while evidence of fast crosstalk within the molecular framework is still observed.
7.	Guo, Y., et al. (author) Reversible Structural Isomerization of Nature's Water Oxidation Catalyst Prior to O-O Bond Formation 2022 In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:26, s. 11736-11747 Journal article (peer-reviewed)abstract Photosynthetic water oxidation is catalyzed by a manganese-calcium oxide cluster, which experiences five "S-states" during a light-driven reaction cycle. The unique "distorted chair"-like geometry of the Mn4CaO5(6)cluster shows structural flexibility that has been frequently proposed to involve "open" and "closed"-cubane forms from the S1 to S3states. The isomers are interconvertible in the S1 and S2states, while in the S3state, the open-cubane structure is observed to dominate inThermosynechococcus elongatus (cyanobacteria) samples. In this work, using density functional theory calculations, we go beyond the S3+Yzstate to the S3nYz•→ S4+Yzstep, and report for the first time that the reversible isomerism, which is suppressed in the S3+Yzstate, is fully recovered in the ensuing S3nYz•state due to the proton release from a manganese-bound water ligand. The altered coordination strength of the manganese-ligand facilitates formation of the closed-cubane form, in a dynamic equilibrium with the open-cubane form. This tautomerism immediately preceding dioxygen formation may constitute the rate limiting step for O2formation, and exert a significant influence on the water oxidation mechanism in photosystem II.
8.	Halldin Stenlid, Joakim, 1987- (author) Computational Studies of Chemical Interactions: Molecules, Surfaces and Copper Corrosion 2017 Doctoral thesis (other academic/artistic)abstract The chemical bond – a corner stone in science and a prerequisite for life – is the focus of this thesis. Fundamental and applied aspects of chemical bonding are covered including the development of new computational methods for the characterization and rationalization of chemical interactions. The thesis also covers the study of corrosion of copper-based materials. The latter is motivated by the proposed use of copper as encapsulating material for spent nuclear fuel in Sweden.In close collaboration with experimental groups, state-of-the-art computational methods were employed for the study of chemistry at the atomic scale. First, oxidation of nanoparticulate copper was examined in anoxic aqueous media in order to better understand the copper-water thermodynamics in relation to the corrosion of copper material under oxygen free conditions. With a similar ambition, the water-cuprite interface was investigated with regards to its chemical composition and reactivity. This was compared to the behavior of methanol and hydrogen sulfide at the cuprite surface.An overall ambition during the development of computational methods for the analysis of chemical bonding was to bridge the gap between molecular and materials chemistry. Theory and results are thus presented and applied in both a molecular and a solid-state framework. A new property, the local electron attachment energy, for the characterization of a compound’s local electrophilicity was introduced. Together with the surface electrostatic potential, the new property predicts and rationalizes regioselectivity and trends of molecular reactions, and interactions on metal and oxide nanoparticles and extended surfaces.Detailed atomistic understanding of chemical processes is a prerequisite for the efficient development of chemistry. We therefore envisage that the results of this thesis will find widespread use in areas such as heterogeneous catalysis, drug discovery, and nanotechnology.
9.	Moth-Poulsen, Kasper, 1978 (author) Molecular Systems for Solar Thermal Energy Storage and Conversion 2013 In: Organic Synthesis and Molecular Engineering. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. ; , s. 179-196 Book chapter (other academic/artistic)abstract Using a synthetic approach to organic materials chemistry, this book sets forth tested and proven methods and practices that make it possible to engineer organic molecules offering special properties and functions. Throughout the book, plenty of real-world examples demonstrate the countless possibilities of creating one-of-a-kind molecules and supramolecular systems to support a broad range of applications. The book explores applications in both materials and bioorganic chemistry, including molecular electronics, energy storage, sensors, nanomedicine, and enzyme engineering.Organic Synthesis and Molecular Engineering consists of fourteen chapters, each one contributed by one or more leading international experts in the field. The contributions are based on a thorough review and analysis of the current literature as well as the authors' firsthand experience in the lab engineering new organic molecules. Designed as a practical lab reference, the book offers:Tested and proven synthetic approaches to organic materials chemistryMethods and practices to successfully engineer functionality into organic moleculesExplanations of the principles and concepts underlying self-assembly and supramolecular chemistryGuidance in selecting appropriate structural units used in the design and synthesis of functional molecules and materialsCoverage of the full range of applications in materials and bioorganic chemistryA full chapter on graphene, a new topic generating intense researchOrganic Synthesis and Molecular Engineering begins with core concepts, molecular building blocks, and synthetic tools. Next, it explores molecular electronics, supramolecular chemistry and self-assembly, graphene, and photoresponsive materials engineering. In short, it offers everything researchers need to fully grasp the underlying theory and then build new molecules and supramolecular systems.
10.	Rahm, Martin, et al. (author) The Molecular Surface Structure of Ammonium and Potassium Dinitramide : A Vibrational Sum Frequency Spectroscopy and Quantum Chemical Study 2011 In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:21, s. 10588-10596 Journal article (peer-reviewed)abstract Vibrational sum frequency spectroscopy (VSFS) and quantum chemical modeling have been employed to investigate the molecular surface structure of ammonium and potassium dinitramide (ADN and KDN) crystals. Identification of key vibrational modes was made possible by performing density functional theory calculations of molecular clusters. The surface of KDN was found to be partly covered with a thin layer of the decomposition product KNO3, which due to its low thickness was not detectable by infrared and Raman spectroscopy. In contrast, ADN exhibited an extremely inhomogeneous surface, on which polarized dinitramide anions were present, possibly together with a thin layer of NH4NO3. The intertwined use of theoretical and experimental tools proved indispensable in the analysis of these complex surfaces. The experimental verification of polarized and destabilized dinitramide anions stresses the importance of designing surface-active polymer support, stabilizers, and/or coating agents, in order to enable environmentally friendly ADN-based solid-rocket propulsion.
11.	Sun, Bing, et al. (author) Ion transport in polycarbonate based solid polymer electrolytes : experimental and computational investigations 2016 In: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 18:14, s. 9504-9513 Journal article (peer-reviewed)abstract Among the alternative host materials for solid polymer electrolytes (SPEs), polycarbonates have recently shown promising functionality in all-solid-state lithium batteries from ambient to elevated temperatures. While the computational and experimental investigations of ion conduction in conventional polyethers have been extensive, the ion transport in polycarbonates has been much less studied. The present work investigates the ionic transport behavior in SPEs based on poly(trimethylene carbonate) (PTMC) and its co-polymer with epsilon-caprolactone (CL) via both experimental and computational approaches. FTIR spectra indicated a preferential local coordination between Li+ and ester carbonyl oxygen atoms in the P(TMC20CL80) co-polymer SPE. Diffusion NMR revealed that the co-polymer SPE also displays higher ion mobilities than PTMC. For both systems, locally oriented polymer domains, a few hundred nanometers in size and with limited connections between them, were inferred from the NMR spin relaxation and diffusion data. Potentiostatic polarization experiments revealed notably higher cationic transference numbers in the polycarbonate based SPEs as compared to conventional polyether based SPEs. In addition, MD simulations provided atomic-scale insight into the structure-dynamics properties, including confirmation of a preferential Li+-carbonyl oxygen atom coordination, with a preference in coordination to the ester based monomers. A coupling of the Li-ion dynamics to the polymer chain dynamics was indicated by both simulations and experiments.
12.	Bannan, T. J., et al. (author) A method for extracting calibrated volatility information from the FIGAERO-HR-ToF-CIMS and its experimental application 2019 In: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 12:3, s. 1429-1439 Journal article (peer-reviewed)abstract The Filter Inlet for Gases and AEROsols (FIGAERO) is an inlet specifically designed to be coupled with the Aerodyne High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS). The FIGAERO-HR-ToF-CIMS provides simultaneous molecular information relating to both the gas- and particle-phase samples and has been used to extract vapour pressures (VPs) of the compounds desorbing from the filter whilst giving quantitative concentrations in the particle phase. However, such extraction of vapour pressures of the measured particle-phase components requires use of appropriate, well-defined, reference compounds. Vapour pressures for the homologous series of polyethylene glycols (PEG) ((H-(O-CH 2 CH 2 ) n -OH) for n = 3 to n = 8), covering a range of vapour pressures (VP) (10 -1 to 10 -7 Pa) that are atmospherically relevant, have been shown to be reproduced well by a range of different techniques, including Knudsen Effusion Mass Spectrometry (KEMS). This is the first homologous series of compounds for which a number of vapour pressure measurement techniques have been found to be in agreement, indicating the utility as a calibration standard, providing an ideal set of benchmark compounds for accurate characterization of the FIGAERO for extracting vapour pressure of measured compounds in chambers and the real atmosphere. To demonstrate this, single-component and mixture vapour pressure measurements are made using two FIGAERO-HR-ToF-CIMS instruments based on a new calibration determined from the PEG series. VP values extracted from both instruments agree well with those measured by KEMS and reported values from literature, validating this approach for extracting VP data from the FIGAERO. This method is then applied to chamber measurements, and the vapour pressures of known products are estimated. © 2019 Author(s).
13.	Franz, Jan, 1973 (author) Some new theoretical tools for the study of electronically excited states of molecules 2010 In: Technical University Chemnitz. Conference paper (other academic/artistic)
14.	Guo, Y. D., et al. (author) Identification of highly oxygenated organic molecules and their role in aerosol formation in the reaction of limonene with nitrate radical 2022 In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:17, s. 11323-11346 Journal article (peer-reviewed)abstract Nighttime NO3-initiated oxidation of biogenic volatile organic compounds (BVOCs) such as monoterpenes is important for the atmospheric formation and growth of secondary organic aerosol (SOA), which has significant impact on climate, air quality, and human health. In such SOA formation and growth, highly oxygenated organic molecules (HOM) may be crucial, but their formation pathways and role in aerosol formation have yet to be clarified. Among monoterpenes, limonene is of particular interest for its high emission globally and high SOA yield. In this work, HOM formation in the reaction of limonene with nitrate radical (NO3) was investigated in the SAPHIR chamber (Simulation of Atmospheric PHotochemistry In a large Reaction chamber). About 280 HOM products were identified, grouped into 19 monomer families, 11 dimer families, and 3 trimer families. Both closed-shell products and open-shell peroxy radicals (RO2 center dot) 2 were observed, and many of them have not been reported previously. Monomers and dimers accounted for 47% and 47% of HOM concentrations, respectively, with trimers making up the remaining 6 %. In the most abundant monomer families, C10H15-17NO6-14, carbonyl products outnumbered hydroxyl products, indicating the importance of RO2 center dot termination by unimolecular dissociation. Both RO2 center dot autoxidation and alkoxy-peroxy pathways were found to be important processes leading to HOM. Time-dependent concentration profiles of monomer products containing nitrogen showed mainly second-generation formation patterns. Dimers were likely formed via the accretion reaction of two monomer RO2 center dot , and HOM-trimers via the accretion reaction between monomer RO2 center dot and dimer RO2 center dot. Trimers are suggested to play an important role in new particle formation (NPF) observed in our experiment. A HOM yield of 1.5%(+1.7%)(-0.7%) was estimated considering only first-generation products. SOA mass growth could be reasonably explained by HOM condensation on particles assuming irreversible uptake of ultra-low volatility organic compounds (ULVOCs), extremely low volatility organic compounds (ELVOCs), and low volatility organic compounds (LVOCs). This work provides evidence for the important role of HOM formed via the limonene +NO3 reaction in NPF and growth of SOA particles.
15.	Hedlund, Artur, et al. (author) Microstructures of cellulose coagulated in water and alcohols from 1-ethyl-3-methylimidazolium acetate : contrasting coagulation mechanisms 2019 In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 26:3, s. 1545-1563 Journal article (peer-reviewed)abstract Abstract: Coagulation of cellulose solutions is a process whereby many useful materials with variable microstructures and properties can be produced. This study investigates the complexity of the phase separation that generates the structural heterogeneity of such materials. The ionic liquid, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), and a co-solvent, dimethylsulfoxide (DMSO), are used to dissolve microcrystalline cellulose in concentrations from 5 to 25 wt%. The solutions are coagulated in water or 2-propanol (2PrOH). The coagulated material is then washed and solvent exchanged (water → 2PrOH → butanone → cyclohexane) in order to preserve the generated microstructures upon subsequent drying before analysis. Sweep electron microscopy images of 50 k magnification reveal open-pore fibrillar structures. The crystalline constituents of those fibrils are estimated using wide-angle X-ray spectroscopy and specific surface area data. It is found that the crystalline order or crystallite size is reduced by an increase in cellulose concentration, by the use of the co-solvent DMSO, or by the use of 2PrOH instead of water as the coagulant. Because previous theories cannot explain these trends, an alternative explanation is presented here focused on solid–liquid versus liquid–liquid phase separations. Graphical abstract: [Figure not available: see fulltext.].
16.	Kong, Xiangrui, et al. (author) Molecular Characterization of Emissions from a Residential Wood Burning Boiler 2021 In: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 754 Journal article (peer-reviewed)
17.	Le Breton, Michael, 1986, et al. (author) Application of a FIGAERO ToF CIMS for on-line characterization of real-world fresh and aged particle emissions from buses 2019 In: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 53:3, s. 244-259 Journal article (peer-reviewed)abstract © 2019, © 2019 The Author(s). Published with license by Taylor & Francis Group, LLC. On-line chemical characterization of real-world particle emissions from 13 transit buses was performed using a chemical ionization mass spectrometer (CIMS) equipped with a filter inlet for gases and aerosols (FIGAERO). In addition to the fresh emissions the emissions were artificially aged using a potential aerosol mass reactor (Go:PAM). The buses studied were running on different fuel types (diesel, compressed natural gas, and rapeseed methyl ester) and exhaust after-treatment systems (selective catalytic reduction (SCR), exhaust gas recirculation (EGR), and a three-way catalyst). When evaluating emissions from passing exhaust plumes using the FIGAERO ToF-CIMS, two technical features were highlighted from this work, the use of high mass calibrants and the factor enhancement method to be able to filter important compounds from mass spectra including hundreds of species. Here, acetate was used as the reagent ion to enable detection of highly oxygenated species in the exhaust particle emissions with potential high toxicity and/or secondary organic aerosol formation (SOA) potential. The acetate ionization scheme accounted for 4% to 46% of the total emitted particulate mass through identification of 61 species in the spectra. For aged emission the various fuel types provided overlapping species that could explain up to 19% of the aged emissions. This is hypothesized to come from the oxidation of engine lubrication oil, thus a common source for various fuels which was further supported by laboratory measurements. Specific markers from the SCR technology, such as urea oxidation products and further byproducts from hydrolysis were identified and attributed to reactions of isocyanic acid.
18.	Le Breton, Michael, 1986, et al. (author) Chlorine oxidation of VOCs at a semi-rural site in Beijing: significant chlorine liberation from ClNO2 and subsequent gas- and particle-phase Cl-VOC production 2018 In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:17, s. 13013-13030:18, s. 13013-13030 Journal article (peer-reviewed)abstract Nitryl chloride (ClNO2) accumulation at night acts as a significant reservoir for active chlorine and impacts the following day's photochemistry when the chlorine atom is liberated at sunrise. Here, we report simultaneous measurements of N2O5 and a suite of inorganic halogens including ClNO2 and reactions of chloride with volatile organic compounds (Cl-VOCs) in the gas and particle phases utilising the Filter Inlet for Gas and AEROsols time-of-flight chemical ionisation mass spectrometer (FIGAERO-ToF-CIMS) during an intensive measurement campaign 40 km northwest of Beijing in May and June 2016. A maximum mixing ratio of 2900 ppt of ClNO2 was observed with a mean campaign nighttime mixing ratio of 487 ppt, appearing to have an anthropogenic source supported by correlation with SO2, CO and benzene, which often persisted at high levels after sunrise until midday. This was attributed to such high mixing ratios persisting after numerous e-folding times of the photolytic lifetime enabling the chlorine atom production to reach 2.3 x 10(5) molecules cm(-3) from ClNO2 alone, peaking at 09:30 LT and up to 8.4 x 10(5) molecules cm(-3) when including the supporting inorganic halogen measurements. Cl-VOCs were observed in the particle and gas phases for the first time at high time resolution and illustrate how the iodide ToF-CIMS can detect unique markers of chlorine atom chemistry in ambient air from both biogenic and anthropogenic sources. Their presence and abundance can be explained via time series of their measured and steady-state calculated precursors, enabling the assessment of competing OH and chlorine atom oxidation via measurements of products from both of these mechanisms and their relative contribution to secondary organic aerosol (SOA) formation.
19.	Li, J. J., et al. (author) Characterization of Aerosol Aging Potentials at Suburban Sites in Northern and Southern China Utilizing a Potential Aerosol Mass (Go:PAM) Reactor and an Aerosol Mass Spectrometer 2019 In: Journal of Geophysical Research-Atmospheres. - : American Geophysical Union (AGU). - 2169-897X .- 2169-8996. ; 124:10, s. 5629-5649 Journal article (peer-reviewed)abstract Aerosol mass spectrometry was used to characterize submicron aerosols before and after aging in a Gothenburg Potential Aerosol Mass (Go:PAM) reactor at two suburban sites in China, one in northern China at Changping (CP), Beijing, and a second in southern China at Hong Kong (HK). Organic aerosol (OA) dominated in the ambient nonrefractory particulate matter <1m (NR-PM1) for both CP (42-71%) and HK (43-61%), with a large contribution from secondary OA factors that were semivolatile oxygenated (SVOOA) and low-volatility oxygenated (LVOOA). Under constant OH exposure, OA enhancement (78-98%) dominated the NR-PM1 mass increment at both sites, while nitrate was enhanced the most among the inorganic species (7-9%). Overall, the CP site exhibited higher OA oxidation potential and more enhancement of SVOOA than LVOOA (7.5 vs. 2.7g/m(3)), but the reverse was observed in HK (0.8 vs. 2.6g/m(3)). In CP, more enhancement of the less oxygenated SVOOA suggests that aerosol aging was more sensitive to the abundant locally emitted primary OA and volatile organic compound precursors. On the contrary, the more formation of the highly oxidized LVOOA in HK indicates that aerosol aging mainly escalated the degree of oxygenation of OA as ambient aerosol was already quite aged and there was a lack of volatile organic compound precursors. The comparative measurements using the same oxidation system reveal distinct key factors and mechanisms that influence secondary aerosol formation in two suburban locations in China, providing scientific insights to assist formulation of location-specific mitigation measures of secondary pollution. Plain Language Summary Atmospheric submicron particles have significant impacts on the climate and human health. A large part of these particles are formed secondarily through successive aging of primary emissions. To study such aging processes, we used a reactor that can provide highly oxidizing conditions to simulate the oxidation of ambient aerosols at accelerated rates. An online mass spectrometer was connected after the reactor to measure changes in aerosol mass concentration and chemical composition between the ambient samples and the oxidized ones. We presented the first comparative measurements of the aging potentials of ambient aerosols in two suburban sites in northern and southern China (Changping District in Beijing, and Hong Kong). Results showed that generally aerosols at the Changping site had higher aging potentials after passing through the oxidation reactor, probably due to more local emissions of precursors, while air masses in Hong Kong were already in a higher oxidation state with lower aging potentials, mainly because of strong impacts from long-range transported pollution sources. Distinct aerosol aging pathways related to different ambient precursors were observed at the two sites. Understanding of the different characteristics of aerosol aging processes can lead to advances in air quality modeling and pollution management.
20.	Mohr, Claudia, et al. (author) Molecular identification of organic vapors driving atmospheric nanoparticle growth 2019 In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10 Journal article (peer-reviewed)abstract Particles formed in the atmosphere via nucleation provide about half the number of atmospheric cloud condensation nuclei, but in many locations, this process is limited by the growth of the newly formed particles. That growth is often via condensation of organic vapors. Identification of these vapors and their sources is thus fundamental for simulating changes to aerosol-cloud interactions, which are one of the most uncertain aspects of anthropogenic climate forcing. Here we present direct molecular-level observations of a distribution of organic vapors in a forested environment that can explain simultaneously observed atmospheric nanoparticle growth from 3 to 50nm. Furthermore, the volatility distribution of these vapors is sufficient to explain nanoparticle growth without invoking particle-phase processes. The agreement between observed mass growth, and the growth predicted from the observed mass of condensing vapors in a forested environment thus represents an important step forward in the characterization of atmospheric particle growth.
21.	Sznitko, L., et al. (author) Low-threshold stimulated emission from lysozyme amyloid fibrils doped with a blue laser dye 2015 In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 106:2 Journal article (peer-reviewed)abstract © 2015 AIP Publishing LLC. Amyloid fibrils are excellent self-assembling nanotemplates for organic molecules such as dyes. Here, we demonstrate that laser dye-doped lysozyme type fibrils exhibit significantly reduced threshold for stimulated emission compared to that observed in usual matrices. Laser action was studied in slab planar waveguides of the amyloids doped with Stilbene 420 laser dye prepared using a film casting technique. The lowering of the threshold of stimulated emission is analyzed in the context of intrinsic structure of the amyloid nanotemplates, electrostatic interaction of different microstructures with dye molecules, as well as material properties of the cast layers. All these factors are considered to be of importance for introducing gain for random laser operation.
22.	Swerin, Agne, et al. (author) Probing molecular, nanoscale and adhesive forces related to fiber-fiber bonding and optimized surface interactions 2009 In: International Conference on Nanotechnology for the Forest Products Industry 2009. - Edmonton Canada. - 9781615679812 ; , s. 229-283 Conference paper (peer-reviewed)
23.	Barišić, Antun, et al. (author) Experimental Data Contributing to the Elusive Surface Charge of Inert Materials in Contact with Aqueous Media 2021 In: Colloids and interfaces. - : MDPI. - 2504-5377. ; 5:1 Journal article (other academic/artistic)abstract We studied the charging of inert surfaces (polytetrafluoroethylene, i.e., PTFE; graphite; graphene; and hydrophobic silica) using classical colloid chemistry approaches. Potentiometric titrations showed that these surfaces acquired less charge from proton-related reactions than oxide minerals. The data from batch-type titrations for PTFE powder did not show an effect of ionic strength, which was also in contrast with results for classical colloids. In agreement with classical colloids, the electrokinetic results for inert surfaces showed the typical salt level dependence. In some cases, the point of zero net proton charge as determined from mass and tentatively from acid–base titration differed from isoelectric points, which has also been previously observed, for example by Chibowski and co-workers for ice electrolyte interfaces. Finally, we found no evidence for surface contaminations of our PTFE particles before and after immersion in aqueous solutions. Only in the presence of NaCl-containing solutions did cryo-XPS detect oxygen from water. We believe that our low isoelectric points for PTFE were not due to impurities. Moreover, the measured buffering at pH 3 could not be explained by sub-micromolar concentrations of contaminants. The most comprehensive explanation for the various sets of data is that hydroxide ion accumulation occurred at the interfaces between inert surfaces and aqueous solutions.
24.	Andersson, Hanna, 1979, et al. (author) Photochemically Induced Aryl Azide Rearrangement: Solution NMR Spectroscopic Identification of the Rearrangement Product 2017 In: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 82:3, s. 1812-1816 Journal article (peer-reviewed)abstract Photolysis of ethyl 3-azido-4,6-difluorobenzoate at room temperature in the presence of oxygen results in the regioselective formation of ethyl 5,7-difluoro-4-azaspiro[2.4]hepta-1,4,6-triene-1-carboxylate, presumably via the corresponding ketenimine intermediate which undergoes a photochemical four-electron electrocyclization followed by a rearrangement. The photorearrangement product was identified by multinuclear solution NMR spectroscopic techniques supported by DFT calculations.
25.	Antonsen, Simen, et al. (author) Atmospheric Chemistry of tert-butylamine and AMP 2017 In: Energy Procedia. Volume 114, 2017, Pages 1026-103213th International Conference on Greenhouse Gas Control Technologies, GHGT 2016; Lausanne; Switzerland; 14 November 2016 through 18 November 2016. - : Elsevier BV. - 1876-6102. Conference paper (peer-reviewed)abstract © 2017 The Authors. The atmospheric chemistry of (CH 3 ) 3 CNH 2 (tert-butylamine, tBA) and (CH 3 ) 2 (CH 2 OH)CNH 2 (2-amino-2-methyl-1-propanol, AMP) has been studied by quantum chemistry methods and in photo-oxidation experiments in the EUPHORE chamber in Valencia (Spain). Aerosol formation and composition has been quantified. Yields of nitramines and other products in the photo-oxidations have been determined and complete photo-oxidation schemes including branching between the major reaction routes have been obtained. Published by Elsevier Ltd.
26.	Banerjee, Ambar, 1985-, et al. (author) Accessing metal-specific orbital interactions in C–H activation with resonant inelastic X-ray scattering 2024 In: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 15:7, s. 2398-2409 Journal article (peer-reviewed)abstract Photochemically prepared transition-metal complexes are known to be effective at cleaving the strong C–H bonds of organic molecules in room temperature solutions. There is also ample theoretical evidence that the two-way, metal to ligand (MLCT) and ligand to metal (LMCT), charge-transfer between an incoming alkane C–H group and the transition metal is the decisive interaction in the C–H activation reaction. What is missing, however, are experimental methods to directly probe these interactions in order to reveal what determines reactivity of intermediates and the rate of the reaction. Here, using quantum chemical simulations we predict and propose future time-resolved valence-to-core resonant inelastic X-ray scattering (VtC-RIXS) experiments at the transition metal L-edge as a method to provide a full account of the evolution of metal–alkane interactions during transition-metal mediated C–H activation reactions. For the model system cyclopentadienyl rhodium dicarbonyl (CpRh(CO)2), we demonstrate, by simulating the VtC-RIXS signatures of key intermediates in the C–H activation pathway, how the Rh-centered valence-excited states accessible through VtC-RIXS directly reflect changes in donation and back-donation between the alkane C–H group and the transition metal as the reaction proceeds via those intermediates. We benchmark and validate our quantum chemical simulations against experimental steady-state measurements of CpRh(CO)2 and Rh(acac)(CO)2 (where acac is acetylacetonate). Our study constitutes the first step towards establishing VtC-RIXS as a new experimental observable for probing reactivity of C–H activation reactions. More generally, the study further motivates the use of time-resolved VtC-RIXS to follow the valence electronic structure evolution along photochemical, photoinitiated and photocatalytic reactions with transition metal complexes.
27.	Benselfelt, Tobias, 1989- (author) Design of Cellulose-based Materials by Supramolecular Assemblies 2019 Doctoral thesis (other academic/artistic)abstract Due to climate change and plastic pollution, there is an increasing demand for bio-based materials with similar properties to those of common plastics yet biodegradable. In this respect, cellulose is a strong candidate that is already being refined on a large industrial scale, but the properties differ significantly from those of common plastics in terms of shapeability and water-resilience.This thesis investigates how supramolecular interactions can be used to tailor the properties of cellulose-based materials by modifying cellulose surfaces or control the assembly of cellulose nanofibrils (CNFs). Most of the work is a fundamental study on interactions in aqueous environments, but some material concepts are presented and potential applications are discussed.The first part deals with the modification of cellulose by the spontaneous adsorption of xyloglucan or polyelectrolytes. The results indicate that xyloglucan adsorbs to cellulose due to the increased entropy of water released from the surfaces, which is similar to the increased entropy of released counter-ions that drives polyelectrolyte adsorption. The polyelectrolyte adsorption depends on the charge of the cellulose up to a limit after which the charge density affects only the first adsorbed layer in a multilayer formation.Latex nanoparticles with polyelectrolyte coronas can be adsorbed onto cellulose in order to prepare hydrophobic cellulose surfaces with strong and ductile wet adhesion, provided the glass transition of the core is below the ambient temperature.The second part of the thesis seeks to explain the interactions between different types of cellulose nanofibrils in the presence of different ions, using a model consisting of ion-ion correlation and specific ion effects, which can be employed to rationally design water-resilient and transparent nanocellulose films. The addition of small amounts of alginate also creates interpenetrating double networks, and these networks lead to a synergy which improves both the stiffness and the ductility of the films in water.A network model has been developed to understand these materials, with the aim to explain the properties of fibril networks, based on parameters such as the aspect ratio of the fibrils, the solidity of the network, and the ion-induced interactions that increase the friction between fibrils. With the help of this network model and the model for ion-induced interactions, we have created films with wet-strengths surpassing those of common plastics, or a ductility suitable for hygroplastic forming into water-resilient and biodegradable packages. Due to their transparency, water content, and the biocompatibility of cellulose, these materials are also suitable for biomaterial or bioelectronics applications.
28.	Brownwood, B., et al. (author) Gas-Particle Partitioning and SOA Yields of Organonitrate Products from NO3-Initiated Oxidation of Isoprene under Varied Chemical Regimes 2021 In: Acs Earth and Space Chemistry. - : American Chemical Society (ACS). - 2472-3452. ; 5:4, s. 785-800 Journal article (peer-reviewed)abstract Alkyl nitrate (AN) and secondary organic aerosol (SOA) from the reaction of nitrate radicals (NO3) with isoprene were observed in the Simulation of Atmospheric PHotochemistry In a large Reaction (SAPHIR) chamber during the NO(3)Isop campaign in August 2018. Based on 15 day-long experiments under various reaction conditions, we conclude that the reaction has a nominally unity molar AN yield (observed range 90 +/- 40%) and an SOA mass yield of OA + organic nitrate aerosol of 13-15% (with similar to 50 mu g m(-3) inorganic seed aerosol and 2-5 mu g m-3 total organic aerosol). Isoprene (5-25 ppb) and oxidant (typically similar to 100 ppb O-3 and 5-25 ppb NO2) concentrations and aerosol composition (inorganic and organic coating) were varied while remaining close to ambient conditions, producing similar AN and SOA yields under all regimes. We observe the formation of dinitrates upon oxidation of the second double bond only once the isoprene precursor is fully consumed. We determine the bulk partitioning coefficient for ANs (K-p similar to 10(-3) m(3) mu g(-1)), indicating an average volatility corresponding to a C-5 hydroxy hydroperoxy nitrate.
29.	Börje, Anna, 1961, et al. (author) New luminescent and redox-active mono- and polynuclear ruthenium(II) and osmium(II) polypyridine complexes 2002 In: Journal of the Chemical Society-Dalton Transactions. - 1472-7773. ; :6, s. 843-848 Journal article (peer-reviewed)abstract A series of mono and polynuclear Ru(II) and Os(II) polypyridine complexes based on the bpy-O-bpy ligand {bpy-O-bpy = bis[4-(2,2'-bipyridinyl)]ether} has been prepared. The redox, absorption and luminescence properties of these species have been measured and compared with those of the [Ru(bpy)(3)](2+) and [Os(bpy)(3)](2+) parent compounds. Electrochemical oxidation involves the metal centers, and occurs reversibly in acetonitrile at room temperature at about +1.30 and +0.85 V vs. SCE, respectively, for the Ru- and Os-based units. Reduction is ligand-centered and features a first irreversible wave followed by several reversible processes. Absorption spectra are essentially the sum of the spectra of the component monometallic species. Luminescence emission is observed both in acetonitrile solution (298 K) and in frozen matrix (77 K), originating from (MLCT)-M-3 states. Homometallic complexes display luminescence properties which are close to that featured by the parent [M(bpy)(3)](2+) species. In heterometallic species luminescence is observed only from the Os-based unit, indicating that efficient energy transfer takes place from the Ru-based to the Os-based moiety. The results indicate that the electronic communication through the bpy-O-bpy bridging ligand is so small that it doesn't substantially modify the properties of the metal units, which are those of the corresponding isolated [M(bpy)(3)](2+) units, but large enough to allow efficient energy transfer through the bridge. The bpy-O-bpy bridging ligand appears thus a promising component for the synthesis of multimetallic antenna systems.
30.	Dinér, Peter, 1976, et al. (author) Investigation of site selectivity of the stereoselective deprotonation of cyclohexene oxide using kinetic resolution of isotopic enantiomers in natural abundance 2005 In: TETRAHEDRON-ASYMMETRY. - : Elsevier BV. - 0957-4166 .- 1362-511X. ; 16:15, s. 2665-2671 Journal article (peer-reviewed)
31.	Donahue, N. M., et al. (author) Aging of biogenic secondary organic aerosol via gas-phase OH radical reactions 2012 In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:34, s. 13503-13508 Journal article (peer-reviewed)abstract The Multiple Chamber Aerosol Chemical Aging Study (MUCHACHAS) tested the hypothesis that hydroxyl radical (OH) aging significantly increases the concentration of first-generation biogenic secondary organic aerosol (SOA). OH is the dominant atmospheric oxidant, and MUCHACHAS employed environmental chambers of very different designs, using multiple OH sources to explore a range of chemical conditions and potential sources of systematic error. We isolated the effect of OH aging, confirming our hypothesis while observing corresponding changes in SOA properties. The mass increases are consistent with an existing gap between global SOA sources and those predicted in models, and can be described by a mechanism suitable for implementation in those models.
32.	Edhborg, Fredrik, 1990, et al. (author) Singlet Energy Transfer in Anthracene-Porphyrin Complexes: Mechanism, Geometry, and Implications for Intramolecular Photon Upconversion 2019 In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 123:46, s. 9934-9943 Journal article (peer-reviewed)abstract In this work we show that the mechanism for singlet excitation energy transfer (SET) in coordination complexes changes upon changing a single atom. SET is governed by two different mechanisms; Förster resonance energy transfer (FRET) based on Coulombic, through-space interactions, or Dexter energy transfer relying on exchange, through-bond interactions. On the basis of time-resolved fluorescence and transient absorption measurements, we conduct a mechanistic study of SET from a set of photoexcited anthracene donors to axially coordinated porphyrin acceptors, revealing the effect of coordination geometry and a very profound effect of the porphyrin central metal atom. We found that FRET is the dominating mechanism of SET for complexes with zinc-octaethylporphyrin (ZnOEP) as the acceptor, while Dexter energy transfer is the dominating mechanism of SET in a corresponding ruthenium complex (RuOEP). In addition, by analyzing the coordination geometry of the complexes and its temperature dependence, the binding angle potential energy of axially coordinated porphyrin complexes could be estimated. The results of this study are of fundamental importance and are discussed with respect to the consequences for developing intramolecular triplet-Triplet annihilation photon upconversion in coordination complexes.
33.	Emanuelsson, Eva U., et al. (author) Formation of anthropogenic secondary organic aerosol (SOA) and its influence on biogenic SOA properties 2013 In: Atmos. Chem. Phys.. - : Copernicus Publications. - 1680-7324. ; 13:5, s. 2837-2855 Journal article (peer-reviewed)abstract Secondary organic aerosol (SOA) formation from mixed anthropogenic and biogenic precursors has been studied exposing reaction mixtures to natural sunlight in the SAPHIR chamber in Jülich, Germany. In this study aromatic compounds served as examples of anthropogenic volatile organic compound (VOC) and a mixture of α-pinene and limonene as an example for biogenic VOC. Several experiments with exclusively aromatic precursors were performed to establish a relationship between yield and organic aerosol mass loading for the atmospheric relevant range of aerosol loads of 0.01 to 10 μg m−3. The yields (0.5 to 9%) were comparable to previous data and further used for the detailed evaluation of the mixed biogenic and anthropogenic experiments. For the mixed experiments a number of different oxidation schemes were addressed. The reactivity, the sequence of addition, and the amount of the precursors influenced the SOA properties. Monoterpene oxidation products, including carboxylic acids and dimer esters were identified in the aged aerosol at levels comparable to ambient air. OH radicals were measured by Laser Induced Fluorescence, which allowed for establishing relations of aerosol properties and composition to the experimental OH dose. Furthermore, the OH measurements in combination with the derived yields for aromatic SOA enabled application of a simplified model to calculate the chemical turnover of the aromatic precursor and corresponding anthropogenic contribution to the mixed aerosol. The estimated anthropogenic contributions were ranging from small (≈8%) up to significant fraction (>50%) providing a suitable range to study the effect of aerosol composition on the aerosol volatility (volume fraction remaining (VFR) at 343 K: 0.86–0.94). The aromatic aerosol had higher oxygen to carbon ratio O/C and was less volatile than the biogenic fraction. However, in order to produce significant amount of aromatic SOA the reaction mixtures needed a higher OH dose that also increased O/C and provided a less volatile aerosol. The SOA yields, O/C, and f44 (the mass fraction of CO2+ ions in the mass spectra which can be considered as a measure of carboxylic groups) in the mixed photo-chemical experiments could be described as linear combinations of the corresponding properties of the pure systems. For VFR there was in addition an enhancement effect, making the mixed aerosol significantly less volatile than what could be predicted from the pure systems. A strong positive correlation was found between changes in volatility and O/C with the exception during dark hours where the SOA volatility decreased while O/C did not change significantly. Thus, this change in volatility under dark conditions as well as the anthropogenic enhancement is due to chemical or morphological changes not affecting O/C.
34.	Fagan, V., et al. (author) COMPARE analysis of the toxicity of an iminoquinone derivative of the imidazo[5,4-f]benzimidazoles with NAD(P)H:quinone Oxidoreductase 1 (NQO1) activity and computational docking of quinones as NQO1 substrates 2012 In: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 20:10, s. 3223-3232 Journal article (peer-reviewed)abstract Synthesis and cytotoxicity of imidazo[5,4-f]benzimidazolequinones and iminoquinone derivatives is described, enabling structure-activity relationships to be obtained. The most promising compound (an iminoquinone derivative) has undergone National Cancer Institute (NCI) 60 cell line (single and five dose) screening, and using the NCI COMPARE program, has shown correlation to NQO1 activity and to other NQO1 substrates. Common structural features suggest that the iminoquinone moiety is significant with regard to NQO1 specificity. Computational docking into the active site of NQO1 was performed, and the first comprehensive mitomycin C (MMC)-NQO1 docking study is presented. Small distances for hydride reduction and high binding affinities are characteristic of MMC and of iminoquinones showing correlations with NQO1 via COMPARE analysis. Docking also indicated that the presence of a substituent capable of hydrogen bonding to the His194 residue is important in influencing the orientation of the substrate in the NQO1 active site, leading to more efficient reduction. (C) 2012 Elsevier Ltd. All rights reserved.
35.	Faxon, Cameron, et al. (author) Characterization of organic nitrate constituents of secondary organic aerosol (SOA) from nitrate-radical-initiated oxidation of limonene using high-resolution chemical ionization mass spectrometry 2018 In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18, s. 5467-5481 Journal article (peer-reviewed)abstract The gas-phase nitrate radical (NO 3 • ) initiated oxidation of limonene can produce organic nitrate species with varying physical properties. Low-volatility products can contribute to secondary organic aerosol (SOA) formation and organic nitrates may serve as a NO x reservoir, which could be especially important in regions with high biogenic emissions. This work presents the measurement results from flow reactor studies on the reaction of NO 3 • with limonene using a High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) combined with a Filter Inlet for Gases and AEROsols (FIGAERO). Major condensed-phase species were compared to those in the Master Chemical Mechanism (MCM) limonene mechanism, and many non-listed species were identified. The volatility properties of the most prevalent organic nitrates in the produced SOA were determined. Analysis of multiple experiments resulted in the identification of several dominant species (including C 10 H 15 NO 6 , C 10 H 17 NO 6 , C 8 H 11 NO 6 , C 10 H 17 NO 7 , and C 9 H 13 NO 7 ) that occurred in the SOA under all conditions considered. Additionally, the formation of dimers was consistently observed and these species resided almost completely in the particle phase. The identities of these species are discussed, and formation mechanisms are proposed. Cluster analysis of the desorption temperatures corresponding to the analyzed particle-phase species yielded at least five distinct groupings based on a combination of molecular weight and desorption profile. Overall, the results indicate that the oxidation of limonene by NO 3 • produces a complex mixture of highly oxygenated monomer and dimer products that contribute to SOA formation.
36.	Ghazzali, Mohamed I D M, 1974, et al. (author) Syntheses, crystal structures, optical limiting properties, and DFT calculations of three thiophene-2-aldazine Schiff base derivatives 2007 In: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 31:10, s. 1777-1784 Journal article (peer-reviewed)abstract The syntheses, characterizations and structural determinations of N,N'-bis(thiophenyl-2-methylene)hydrazine 1, N,N'-bis(4-bromothiophenyl-2-methylene)hydrazine 2 and N,N'-bis(5-bromothiophenyl-2-methylene)hydrazine 3 are presented. The materials show third-ordernonlinear behaviour with transmissions of 20, 22 and 18 μJ for an input energy of 150 μJ. The4- and 5-bromothiophenic structures show Br...Br interactions of 3.562 and 3.626 Å, respectively.Analysis of bromine containing aromatic compounds in the Cambridge CrystallographicDatabase (CSD) showed the expected angle dependences of the Br...Br interactions dividing theseinto ‘‘type I’’ and ‘‘type II’’. A semi-quantitative agreement was found between the CSD data anda model derived form calculated electrostatic potentials.
37.	Hallquist, Mattias, 1969, et al. (author) Photochemical smog in China: scientific challenges and implications for air-quality policies 2016 In: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 3:4, s. 401-403 Journal article (peer-reviewed)abstract In large areas of China severe air pollution events pose a significant threat to human health, ecosystems and climate. Current reduction of primary emissions will also affect secondary pollutants such as ozone (O3) and particulate matter (PM), but the magnitude of the effects is uncertain. Major scientific challenges are related to the formation of O3 and secondary particulate matter including Secondary Organic Aerosols (SOA). Large uncertainties also remain regarding the interactions of soot, SOA and O3 under the influence of different SO2, NOX and VOC concentrations. To improve the understanding of these secondary atmospheric interactions in China, scientific areas of central importance for photochemically induced air pollutants have been identified. In addition to the scientific challenges, results from research need to be synthesized across several disciplines and communicated to stakeholders affected by air pollution and to policy makers responsible for developing abatement strategies. Development of these science-policy interactions can benefit from experience gained under the UN ECE Convention on Long Range Transboundary Air Pollution (LRTAP)
38.	Hedenstedt, Kristoffer, 1979, et al. (author) Study of Hypochlorite Reduction Related to the Sodium Chlorate Process 2016 In: Electrocatalysis. - : Springer Science and Business Media LLC. - 1868-2529 .- 1868-5994. ; 7:4, s. 326-335 Journal article (peer-reviewed)abstract Reduction of hypochlorite is the most important side reaction in the sodium chlorate reactor leading to high energy losses. Today chromate is added to the reactor solution to minimize the hypochlorite reduction but a replacement is necessary due to health and environmental risks with chromate. In order to understand the effect of different substrates on the hypochlorite reduction, α-FeOOH, γ-FeOOH, Cr2O3 and CrOH3 were electrodeposited on titanium and subjected to electrochemical investigations. These substances are commonly found on cathodes in the chlorate process and can serve as model substances for the experimental investigation. The mechanism of hypochlorite reduction was also studied using DFT calculations in which the reaction at Fe(III) and Cr(III) surface sites were considered in order to single out the electrocatalytic properties. The experimental results clearly demonstrated that the chromium films completely block the reduction of hypochlorite, while for the iron oxyhydroxides the process can readily occur. Since the electrocatalytic properties per se were shown by the DFT calculations to be very similar for Fe(III) and Cr(III) sites in the oxide matrix, other explanations for the blocking ability of chromium films are addressed and discussed in the context of surface charging, reduction of anions and conduction in the deposited films. The main conclusion is that the combined effect of electronic properties and reduction of negatively charged ions can explain the reduction kinetics of hypochlorite and the effect of chromate in the chlorate process.
39.	Kolavali, Reddysuresh, 1983, et al. (author) The sorption of monovalent cations onto wood flour and holocelluloses of Norway spruce: molecular interactions during LiCl impregnation 2017 In: Holzforschung. - : Walter de Gruyter GmbH. - 1437-434X .- 0018-3830. ; 71:5, s. 373-381 Journal article (peer-reviewed)abstract Active functional groups and interactions involved in the sorption of Li+ ions from an aqueous LiCl solution onto the Norway spruce sapwood (sW) flour have been investigated. To this purpose, sW was delignified by peracetic acid (PAA) treatments and the resulting holocelluloses (HC6 h, HC24 h, HC51 h, HC72 h, where the lower case data indicate the PAA treatment time) with various lignin contents were immersed in aqueous solution of LiCl and the sorption effects were studied by flame atomic emission spectroscopy (FAES), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The Brunauer- Emmett-Teller (BET) specific surface area increased from 1.5±0.0 m2g−1 to 2.4±0.1 m2g−1 for HC6 h, and from 1.6±0.03 m2g−1 to 2.7±0.6 m2g−1 for HC72 h upon LiCl treatment. It was found that Li+/Cl− retention occurs predominantly via O-containing functionalities and the carbohydrate-rich samples sorbed more Li+. Upon LiCl treatment, the mobility and accessibility of the wood matrix was enhanced, possibly by interference of the introduced ions with the existing intermolecular bonds.
40.	Kourtchev, Ivan, et al. (author) Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols 2016 In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6 Journal article (peer-reviewed)abstract Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.
41.	Kristensen, Kasper, et al. (author) High-Molecular Weight Dimer Esters Are Major Products in Aerosols from α-Pinene Ozonolysis and the Boreal Forest 2016 In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 3:8, s. 280-285 Journal article (peer-reviewed)abstract This study investigates the contribution of high-molecular weight dimer esters to laboratory-generated α-pinene gas- and particle-phase secondary organic aerosol (SOA) and particulate matter (PM) collected at the Nordic boreal forest site of Hyytiälä, Finland. Laboratory flow reactor experiments (25 °C) show that dimer esters from ozonolysis of α-pinene contribute between 5 and 16% of the freshly formed α-pinene particle-phase SOA mass. An increased level of formation is observed at a higher relative humidity of ∼40%, and the presence of a hydroxyl radical (OH) scavenger is shown to affect the formation of dimer esters. Of the 28 dimer esters identified in laboratory α-pinene SOA, 15 are also observed in ambient PM samples, contributing between 0.5 and 1.6% of the total PM1. The observed esters show good correlation with known α-pinene SOA tracers in collected PM samples. This work reveals an, until now, unrecognized contribution of dimer esters from α-pinene oxidation to boreal forest PM.
42.	Le Breton, Michael, 1986, et al. (author) Online gas- and particle-phase measurements of organosulfates, organosulfonates and nitrooxy organosulfates in Beijing utilizing a FIGAERO ToF-CIMS 2018 In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:14, s. 10355-10371 Journal article (peer-reviewed)abstract A time-of-flight chemical ionization mass spectrometer (CIMS) utilizing the Filter Inlet for Gas and Aerosol (FIGAERO) was deployed at a regional site 40 km north-west of Beijing and successfully identified and measured 17 sulfur-containing organics (SCOs are organo/nitrooxy organosulfates and sulfonates) with biogenic and anthropogenic precursors. The SCOs were quantified using laboratory-synthesized standards of lactic acid sulfate and nitrophenol organosulfate (NP OS). The variation in field observations was confirmed by comparison to offline measurement techniques (orbitrap and high-performance liquid chromatography, HPLC) using daily averages. The mean total (of the 17 identified by CIMS) SCO particle mass concentration was 210 +/- 110 ng m(-3) and had a maximum of 540 ng m(-3), although it contributed to only 2 +/- 1% of the organic aerosol (OA). The CIMS identified a persistent gas-phase presence of SCOs in the ambient air, which was further supported by separate vapour-pressure measurements of NP OS by a Knudsen Effusion Mass Spectrometer (KEMS). An increase in relative humidity (RH) promoted partitioning of SCO to the particle phase, whereas higher temperatures favoured higher gas-phase concentrations. Biogenic emissions contributed to only 19% of total SCOs measured in this study. Here, C10H16NSO7, a monoterpene-derived SCO, represented the highest fraction (10 %) followed by an isoprene-derived SCO. The anthropogenic SCOs with polycyclic aromatic hydrocarbon (PAH) and aromatic precursors dominated the SCO mass loading (51 %) with C11H11SO7, derived from methyl naphthalene oxidation, contributing to 40 ng m(-3) and 0.3% of the OA mass. Anthropogenic-related SCOs correlated well with benzene, although their abundance depended highly on the photochemical age of the air mass, tracked using the ratio between pinonic acid and its oxidation product, acting as a qualitative photochemical clock. In addition to typical anthropogenic and biogenic precursors the biomass-burning precursor nitrophenol (NP) provided a significant level of NP OS. It must be noted that the contribution analysis here is only representative of the detected SCOs. There are likely to be many more SCOs present which the CIMS has not identified. Gas- and particle-phase measurements of glycolic acid suggest that partitioning towards the particle phase promotes glycolic acid sulfate production, contrary to the current formation mechanism suggested in the literature. Furthermore, the HSO4 center dot H2SO4- cluster measured by the CIMS was utilized as a qualitative marker for acidity and indicates that the production of total SCOs is efficient in highly acidic aerosols with high SO42- and organic content. This dependency becomes more complex when observing individual SCOs due to variability of specific VOC precursors.
43.	Li, Jing, et al. (author) Towards the mechanism of electrochemical activity and self-healing of 1 wt% PTSA doped polyaniline in alkyd composite polymer coating : Combined AFM-based studies 2016 In: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 6:23, s. 19111-19127 Journal article (peer-reviewed)abstract A composite solvent-borne alkyd coating with 1 wt% p-toluene sulfonic acid (PTSA) doped polyaniline (PANI) was prepared. The mechanisms of electrochemical activity and self-healing properties of the composite coating were investigated by in situ atomic force microscopy (AFM), intermodulation AFM (ImAFM), electrochemical controlled (EC)-AFM combined with cyclic voltammetry (CV), Kelvin force microscopy (KFM), and Fourier transform infrared spectroscopy (FTIR), as well as open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) methods. The ImAFM demonstrates the multiphase structure of the composite coating and a high compatibility between the doped PANI and alkyd matrix. The CV and EC-AFM results reveal a high electrochemical activity of the doped PANI in the composite coating as well as reversible redox reactions between the emeraldine salt (ES) and leuco emeraldine base (LB) forms. The Volta potential mapping of KFM demonstrates a strong self-healing ability of the doped PANI in air conditions. The good electrochemical connection between the fine network of PANI in the composite coating and metal surface underneath enable the occurrence of reversible redox reaction between the ES/LB forms of doped PANI and a concomitant release of dopant anions both in air and in 3 wt% NaCl solution as demonstrated by OCP and EIS results. These therefore lead to the strong passivation and self-healing effect of the composite coated on the carbon steel surface.
44.	Lopez-Hilfiker, F. D., et al. (author) A novel method for on-line analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO) 2013 In: Atmospheric Measurement Techniques Discussions. - : Copernicus Publications. - 1867-8610. ; 6:5, s. 9347-9395 Journal article (peer-reviewed)abstract We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gas and AEROsol (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the pg m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.
45.	Lopez-Hilfiker, F. D., et al. (author) A novel method for online analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO) 2014 In: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:4, s. 983-1001 Journal article (peer-reviewed)abstract We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gases and AEROsols (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon® (hereafter Teflon) filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the picogram m−3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.
46.	Lutz, Anna, 1986, et al. (author) Gas to Particle Partitioning of Organic Acids in the Boreal Atmosphere 2019 In: Acs Earth and Space Chemistry. - : American Chemical Society (ACS). - 2472-3452. ; 3:7, s. 1279-1287 Journal article (peer-reviewed)abstract Gas to particle partitioning of carboxylic acids was investigated using a high-resolution chemical ionization time-of-flight mass spectrometer (HR-CI-ToF-MS) with the filter inlet for gases and aerosol (FIGAERO). Specifically, the partitioning coefficients of 640 components with unique molecular composition were calculated from an assumed linear relationship between [particle]/[gas] versus the mass of the organic fraction (M-org) according to Raoult's law, i.e., equilibrium phase partitioning. We demonstrate that, using the full data set, most of the compounds do not follow a linear relationship. This is especially the case for low- and high-molecular-weight species. Using a subset of the data, with concurrent low sulfate ambient observations ([SO42- < 0.4 mu g m(-3)), the relationship improved significantly and K-i could be derived from the slope of a linear regression to the data. The 100 species with the highest R-2 (>= 0.7) of this regression are presented. The restrictions during high sulfate conditions can be explained by changes in either the equilibrium conditions (e.g., the activity coeffient, gamma(i)) or uptake kinetics (mass transfer limitation). This study demonstrates that partitioning of compounds in the complex ambient atmosphere follows ideal Raoult's law for some limited conditions and stresses the need for studies also in more polluted environments.
47.	Mohr, C., et al. (author) Ambient observations of dimers from terpene oxidation in the gas phase: Implications for new particle formation and growth 2017 In: Geophysical Research Letters. - 0094-8276. ; 44:6, s. 2958-2966 Journal article (peer-reviewed)abstract We present ambient observations of dimeric monoterpene oxidation products (C16-20HyO6-9) in gas and particle phases in the boreal forest in Finland in spring 2013 and 2014, detected with a chemical ionization mass spectrometer with a filter inlet for gases and aerosols employing acetate and iodide as reagent ions. These are among the first online dual-phase observations of such dimers in the atmosphere. Estimated saturation concentrations of 10(-15) to 10(-6)mu gm(-3) (based on observed thermal desorptions and group-contribution methods) and measured gas-phase concentrations of 10(-3) to 10(-2)mu gm(-3) (similar to 10(6)-10(7)moleculescm(-3)) corroborate a gas-phase formation mechanism. Regular new particle formation (NPF) events allowed insights into the potential role dimers may play for atmospheric NPF and growth. The observationally constrained Model for Acid-Base chemistry in NAnoparticle Growth indicates a contribution of similar to 5% to early stage particle growth from the similar to 60 gaseous dimer compounds. Plain Language Summary Atmospheric aerosol particles influence climate and air quality. We present new insights into how emissions of volatile organic compounds from trees are transformed in the atmosphere to contribute to the formation and growth of aerosol particles. We detected for the first time over a forest, a group of organic molecules, known to grow particles, in the gas phase at levels far higher than expected. Previous measurements had only measured them in the particles. This finding provides guidance on how models of aerosol formation and growth should describe their appearance and fate in the atmosphere.
48.	Napolitano, C., et al. (author) Synthesis, kinase activity and molecular modeling of a resorcylic acid lactone incorporating an amide and a trans-enone in the macrocycle 2012 In: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 68:27-28, s. 5533-5540 Journal article (peer-reviewed)abstract Details for the synthesis of a resorcylic acid lactone (RAL) incorporating a trans-enone and an amide in the macrocyclic ring are provided herein. The sequence included the assembly of three fragments by esterification, olefination, and lactamization. The RAL with the lactam was less potent as an inhibitor of kinases than other RALs investigated. The biological results were rationalized by docking and molecular dynamics simulations of the lactam bound to human ERK2 and comparison with hypothemycin. (c) 2012 Elsevier Ltd. All rights reserved.
49.	Nordin, E. Z., et al. (author) Secondary organic aerosol formation from idling gasoline passenger vehicle emissions investigated in a smog chamber 2013 In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:12, s. 6101-6116 Journal article (peer-reviewed)abstract Gasoline vehicles have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from three passenger vehicles (EURO2-EURO4) were investigated with photo-oxidation experiments in a 6 m(3) smog chamber. The experiments were carried out down to atmospherically relevant organic aerosol mass concentrations. The characterization instruments included a high-resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind of urban areas. After a cumulative OH exposure of similar to 5 x 10(6) cm(-3) h, the formed SOA was 1-2 orders of magnitude higher than the primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f(43) (mass fraction at m/z = 43), approximately two times higher than to the gasoline SOA. However O:C and H:C ratios were similar for the two cases. Classical C-6-C-9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher-order aromatic compounds such as C-10 and C-11 light aromatics, naphthalene and methyl-naphthalenes. We conclude that approaches using only light aromatic precursors give an incomplete picture of the magnitude of SOA formation and the SOA composition from gasoline exhaust.
50.	Pathak, Ravi K., et al. (author) Influence of Ozone and Radical Chemistry on Limonene Organic Aerosol Production and Thermal Characteristics 2012 In: Environmental Science & Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 46:21, s. 11660-11669 Journal article (peer-reviewed)abstract Limonene has a strong tendency to form secondary organic aerosol (SOA) in the atmosphere and in indoor environments. Initial oxidation occurs mainly via ozone or OH radical chemistry. We studied the effect of O3 concentrations with or without a OH radical scavenger (2-butanol) on the SOA mass and thermal characteristics using the Gothenburg Flow Reactor for Oxidation Studies at Low Temperatures and a volatility tandem differential mobility analyzer. The SOA mass using 15 ppb limonene was strongly dependent on O3 concentrations and the presence of a scavenger. The SOA volatility in the presence of a scavenger decreased with increasing levels of O3, whereas without a scavenger, there was no significant change. A chemical kinetic model was developed to simulate the observations using vapor pressure estimates for compounds that potentially contributed to SOA. The model showed that the product distribution was affected by changes in both OH and ozone concentrations, which partly explained the observed changes in volatility, but was strongly dependent on accurate vapor pressure estimation methods. The model–experiment comparison indicated a need to consider organic peroxides as important SOA constituents. The experimental findings could be explained by secondary condensed-phase ozone chemistry, which competes with OH radicals for the oxidation of primary unsaturated products.

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