| 1. |
- Armstrong, David A., et al.
(författare)
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Standard electrode potentials involving radicals in aqueous solution : inorganic radicals (IUPAC Technical Report)
- 2015
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter. - 0033-4545 .- 1365-3075. ; 87:11-12, s. 1139-1150
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Tidskriftsartikel (refereegranskat)abstract
- Recommendations are made for standard potentials involving select inorganic radicals in aqueous solution at 25 degrees C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. The recommended data are summarized in tables of standard potentials, Gibbs energies of formation, radical pK(a)'s, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations.
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| 2. |
- Baránková, Hana, et al.
(författare)
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Hollow cathode and hybrid atmospheric plasma sources
- 2008
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 80:9, s. 1931-1937
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Tidskriftsartikel (refereegranskat)abstract
- Generation and features of the radio frequency (RF) hollow cathode discharge (HCD) are compared for the atmospheric and moderate pressures. The atmospheric-pressure plasma systems, fused hollow cathode (FHC) and hybrid hollow electrode-activated discharge (H-HEAD), are described. Examples of applications where both FHC and H-HEAD have already been employed are given, and potentials for new processes are discussed.
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| 3. |
- Barrozo, Alexandre, et al.
(författare)
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The effect of magnesium ions on triphosphate hydrolysis
- 2017
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 89:6, s. 715-727
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Tidskriftsartikel (refereegranskat)abstract
- The role of metal ions in catalyzing phosphate ester hydrolysis has been the subject of much debate, both in terms of whether they change the transition state structure or mechanistic pathway. Understanding the impact of metal ions on these biologically critical reactions is central to improving our understanding of the role of metal ions in the numerous enzymes that facilitate them. In the present study, we have performed density functional theory studies of the mechanisms of methyl triphosphate and acetyl phosphate hydrolysis in aqueous solution to explore the competition between solvent-and substrate-assisted pathways, and examined the impact of Mg2+ on the energetics and transition state geometries. In both cases, we observe a clear preference for a more dissociative solvent-assisted transition state, which is not significantly changed by coordination of Mg2+. The effect of Mg2+ on the transition state geometries for the two pathways is minimal. While our calculations cannot rule out a substrate-assisted pathway as a possible solution for biological phosphate hydrolysis, they demonstrate that a significantly higher energy barrier needs to be overcome in the enzymatic reaction for this to be an energetically viable reaction pathway.
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| 4. |
- Batten, S. R., et al.
(författare)
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Terminology of Metal-Organic Frameworks and Coordination Polymers (IUPAC recommendations 2013)
- 2013
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Ingår i: Pure and Applied Chemistry. - 1365-3075 .- 0033-4545. ; 85:8, s. 1715-1724
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Tidskriftsartikel (refereegranskat)abstract
- A set of terms, definitions, and recommendations is provided for use in the classi- fication of coordination polymers, networks, and metal–organic frameworks (MOFs). A hier- archical terminology is recommended in which the most general term is coordination poly- mer. Coordination networks are a subset of coordination polymers and MOFs a further subset of coordination networks. One of the criteria an MOF needs to fulfill is that it contains poten- tial voids, but no physical measurements of porosity or other properties are demanded per se. The use of topology and topology descriptors to enhance the description of crystal structures of MOFs and 3D-coordination polymers is furthermore strongly recommended.
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| 5. |
- Bengtsson, Åsa, et al.
(författare)
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Surface complexation and proton-promoted dissolution in aqueous apatite systems
- 2009
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Ingår i: Pure and Applied Chemistry. - : International Union of Pure and Applied Chemistry. - 0033-4545 .- 1365-3075. ; 81:9, s. 1569-1584
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: The dissolution of hydroxyapatite (HAP) and fluorapatite (FAP) has been studied (25 °C, 0.1 M NaCl medium) within the pH ranges 2–11 (FAP) and 4–10 (HAP). A range of techniques has been utilized to achieve understanding in how these two abundant minerals may interact with their natural surroundings (e.g., body fluids and soil environments). Synthetic crystalline HAP and FAP were prepared, and both minerals were found to undergo a phase transformation generated during a dialysis step of the synthetic routes. Surface-deficient layers with the nonstoichiometric compositions Ca8.4(HPO4)1.6(PO4)4.4(OH)0.4 and Ca9(HPO4)2(PO4)4F2 were identified. The equilibrium analysis of experimental solubility data of the two apatite systems was based upon potentiometric titration data, batch experiments, and zeta-potential measurements in combination with information provided by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The analysis required, besides the two solubility equilibria, the formation of surface protonation/deprotonation reactions, re-adsorption processes involving phosphate and fluoride ions as well as an ion exchange reaction (≡F + H2O ⇋ ≡OH + H+ + F–) to fully describe the dissolution characteristics of the two apatite systems. The resulting model also agrees with observations from XPS and solubility data, claiming the formation of CaF2(s) in the most acidic pH range of the FAP system. In addition, calculated isoelectric points (pHiep) are in agreement with values from surface charge measurements showing pHiep (HAP) = 8.1 and pHiep (FAP) = 5.7.
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| 6. |
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| 7. |
- Bohlin, Lars, et al.
(författare)
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Modern pharmacognosy : Connecting biology and chemistry
- 2007
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 79:4, s. 763-774
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Tidskriftsartikel (refereegranskat)abstract
- In many countries today, the number of students selecting chemistry for higher studies is decreasing. At the same time, interest in the environmental aspects of chemistry, green chemistry, and sustainable use of natural products is increasing among the young generation of students. By modernizing and renewing a venerable proven science, pharmacognosy would have a strategic position to connect biology and chemistry. This multidisciplinary subject is important for discovery of novel and unique molecules with drug potential, and for revealing unknown targets, by studying evolutionary structure-activity optimization in nature. In this paper, the overall aim and strategies of our research are presented and exemplified by three different research projects. Natural products are involved in scientific issues important for a sustainable society, and a multidisciplinary subject such as pharmacognosy can, therefore, be useful in increasing future interest in both chemistry and biology.
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| 8. |
- Buchanan, Claire, et al.
(författare)
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Comprehensive multidimensional study of the self-assembly properties of a three residue substituted beta(3) oligoamide
- 2021
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter. - 0033-4545 .- 1365-3075. ; 93:11, s. 1327-1341
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Tidskriftsartikel (refereegranskat)abstract
- Substituted (beta(3) oligoamides form a unique self-assembling system where each monomer folds into a helix containing approximately three (beta(3) amino acids per turn, yielding a geometrically well-defined cylindrical building block that, when N-acylated, is able to self-assemble head-to-tail into nanorods that can reach several 100 mu m length. It was shown in previous works that self-assembly can be achieved with a three residue long oligoamide as well that lacks any intramolecular H-bonds, yet it crystallizes in a helix-like conformation. The self-assembly properties of these small oligoamides are however elusive, suggesting a more complex system than the self-assembly of the H-bond stabilized helical monomers. Here we focus on the self-assembly behaviour of a three residue oligoamide, Ac-beta(3)[LIA] where the letters denote the side chain of the analogous a amino acid. Ac-beta(3)[LIA] can yield highly inhomogeneous suspensions in water with a broad range of large fibrous structures that seem to be very stable, yet occasionally fibre growth is only observed upon heating. The small size of the monomer suggests a highly dynamic equilibrium yet all previous attempts failed to clearly identify low molecular weight species. Therefore a special methodology was employed in this study to characterize the suspensions at different size ranges: SANS that is optimal to measure the small oligomers and cross sectional diameter of the assemblies, DLS that is sensitive to the large populations and therefore the length of the superstructures, and NMR that is sensitive to monomeric and small oligomeric form, in conjunction with IR spectroscopy to probe the folding and AFM to image the morphology of the assemblies. Temperature ramping was used to perturb the system to probe the dynamicity of the self-assembly. It was found that the anomalous self-assembly behaviour of Ac-beta(3)[LIA] is caused by its two stable conformations, a helix-building "horseshoe" fold and a linear conformer. The latter is exclusively found in monomeric form in solution whereas the horseshoe fold is stable in solid phase and in fibrous assemblies. Small oligomers were absent. Thus the self assembly of Ac-beta(3)[LIA] is arrested by the activation energy need of the conformation change; fibre growth might be triggered by conditions that allow increased conformational freedom of the monomers. This observation may be used to develop strategies for controlled switchable self-assembly.
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| 9. |
- Concina, Isabella, et al.
(författare)
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Light harvester band gap engineering in excitonic solar cells : A case study on semiconducting quantum dots sensitized rainbow solar cells
- 2014
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 86:5, s. 575-584
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Tidskriftsartikel (refereegranskat)abstract
- A systematic study on the fabrication of quantum dots sensitized solar cells (QDSSCs) exploiting hybrid networks of semiconducting light harvesters is presented, which shows how the engineering of band gaps of the device components by a very simple technique allows improving the solar energy conversion performances. Panchromatic devices are fabricated and tested, and correspondent functional parameters analyzed in order to highlight both advantages and drawbacks of the most common (CdS, CdSe, PbS) quantum dots applied for light collection in QDSSCs. Judicious engineering of the light harvester layer is demonstrated as a simple and powerful strategy for boosting device performances, through the management of light collection in a rather broad range of solar spectrum and photogenerated charges injection and collection. © 2014 IUPAC & De Gruyter.
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| 10. |
- Cordova, Armando, 1970-, et al.
(författare)
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A sustainable strategy for production and functionalization of nanocelluloses
- 2019
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 0033-4545 .- 1365-3075. ; 91:5, s. 865-874
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Tidskriftsartikel (refereegranskat)abstract
- A sustainable strategy for the neat production and surface functionalization of nanocellulose from wood pulp is disclosed. It is based on the combination of organocatalysis and click chemistry (organoclick chemistry) and starts with nanocellulose production by organic acid catalyzed hydrolysis and esterification of the pulp under neat conditions followed by homogenization. This nanocellulose fabrication route is scalable, reduces energy consumption and the organic acid can be efficiently recycled. Next, the surface is catalytically engineered by organoclick chemistry, which allows for selective and versatile attachment of different organic molecules (e.g. fluorescent probes, catalyst and pharmaceuticals). It also enables binding of metal ions and nanoparticles. This was exemplified by the fabrication of a heterogeneous nanocellulose palladium nanoparticle catalyst, which is used for Suzuki cross-coupling transformations in water. The disclosed surface functionalization methodology is broad in scope and applicable to different nanocelluloses and cellulose based materials as well.
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