| 1. |
- Gusev, Alexey, et al.
(författare)
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Intercontinental transport of persistent organic pollutants : a review of key findings and recommendations of the task force on hemispheric transport of air pollutants and directions for future research
- 2012
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Ingår i: Atmospheric Pollution Research. - 1309-1042. ; 3:4, s. 463-465
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Tidskriftsartikel (refereegranskat)abstract
- The Task Force on Hemispheric Transport of Air Pollution (TF HTAP) was established under the Convention on Long-range Transboundary Air Pollution (CLRTAP) to improve scientific understanding of the intercontinental transport of air pollutants and to deliver policy-relevant information on this issue. The first comprehensive assessment of POP intercontinental transport made by the TF HTAP was compiled in 2010 and published in 2011. The HTAP assessment was made possible by the contributions of a large network of experts in various national and international organizations and is intended to support further development of international policy and regulation of POPs under the frameworks of the UN ECE CLRTAP and the Stockholm Convention on POPs. By summarizing the outcome of past studies on POPs, the assessment highlights the evidence of POP intercontinental transport and the associated threat to human health and the environment. It presents the current state of knowledge on levels of POPs in the environment, emission inventories and projections, modeling of long-range transport and fate in various compartments, interactions with climate change, as well as harmful effects on human health and ecosystems. Two important outcomes of the HTAP 2010 assessment are the summary of key scientific and policy-relevant findings, and the recommendations for further work which include the need to a more fully developed integrated approach to the pollution assessment. In its next phase, which extends to 2015, the Task Force is planning to cooperate across different thematic areas of scientific activity on intercontinental transport of pollution, and exploit synergies of effort in cases where particulate matter (PM), ozone, mercury, and POPs share common sources. It is recognized that a fully integrated approach for building a scientific understanding of POPs in the environment should encompass measurements, modeling results, and emission estimates, and in addition it should more explicitly include assessment of ecosystem effects. (C) Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.
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| 2. |
- Gusev, Alexey, et al.
(författare)
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Mononuclear copper(i) complexes bearing a 3-phenyl-5-(pyridin-4-yl)-1,2,4-triazole ligand: synthesis, crystal structure, TADF-luminescence, and mechanochromic effects
- 2023
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Ingår i: Dalton Transactions. - : ROYAL SOC CHEMISTRY. - 1477-9226 .- 1477-9234. ; 52:41, s. 14995-15008
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Tidskriftsartikel (refereegranskat)abstract
- Three new mononuclear heteroleptic copper(i) halide complexes, [CuL(PPh3)(2)X] (X = Cl, Br, I), based on 3-phenyl-5-(pyridin-4-yl)-1,2,4-triazole (L) and triphenylphosphine (PPh3) ligands, have been prepared by reaction of CuX (X = Cl, Br, I), L and PPh3 in a molar ratio of 1 : 1 : 2 in MeCN solutions. The synthesized complexes exhibit blue light emission in solutions and bright green emission in the crystal state with quantum yields of up to 100%. The luminescence decay analysis and density functional theory calculations revealed that the emission of solid samples at room temperature corresponds to the thermally activated delayed fluorescence, while that at 77 K is assigned to phosphorescence. Utilizing the studied complexes in OLED heterostructures resulted in high-performing green-emitting devices with an external quantum efficiency of up to 13.4%.
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| 3. |
- Gusev, Alexey N., et al.
(författare)
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Novel Zinc Complex with an Ethylenediamine Schiff Base for High-Luminance Blue Fluorescent OLED Applications
- 2019
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 123:18, s. 11850-11859
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Tidskriftsartikel (refereegranskat)abstract
- To explore the photophysical properties of coordination compounds with bright blue fluorescence, an azomethin-zinc complex was synthesized and characterized by various techniques (elemental analysis, thermogravimetry, and IR-mass-spectroscopy). The crystal structure was determined by X-ray diffraction analysis. Through thermal characterization, this complex was proved to have good thermal stability. Photoluminescence spectra were recorded, both in solution and in the solid state, and the complexes showed noteworthy photoluminescence with a maximum in the blue region. The results of time-dependent density functional theory calculations indicated that the origin of luminescence for the title complex is a combination of monomer and excimer emissions. The light emission performance of the zinc complex in organic light emitting diodes was investigated, and the results indicated superior electroluminescence properties as a blue fluorescent light source (max. brightness 17 000 cd/m(2), max. EQE = 5%).
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| 4. |
- Gusev, Alexey N., et al.
(författare)
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Schiff Base Zinc(II) Complexes as Promising Emitters for Blue Organic Light-Emitting Diodes
- 2021
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Ingår i: ACS Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 3:8, s. 3436-3444
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Tidskriftsartikel (refereegranskat)abstract
- Organometallic blue fluorescent Zn(II) Schiff base complexes are synthesized and explored computationally in order to use them in organic electroluminescent heterostructures. Characterization of these pyrazolone-based azomethine-zinc complexes was accomplished by various physicochemical techniques to get insight into their applicability as an active layer in light-emitting diodes. All the complexes demonstrate high thermal stability and remarkable photoluminescence both in solution and in the solid state with maximum in the blue region. Quantum chemical calculations of the first exited electronic state and vertical singlet-singlet electronic transitions by means of time-dependent density functional theory calculations and results show that the origin of the luminescence for the target complexes refers to the intraligand charge transfer within the Schiff bases. The constructed light-emitting diodes demonstrate low input voltage (3.2-4.0 V), brightness at a level of 4300-11,600 Cd m(-2), and external quantum efficiency of up to 3.2%, which is a good value for purely fluorescent organic light-emitting diodes.
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| 5. |
- Gusev, Alexey, et al.
(författare)
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Structure and emission properties of dinuclear copper(i) complexes with pyridyltriazole
- 2023
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Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 13:6, s. 3899-3909
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Tidskriftsartikel (refereegranskat)abstract
- A new series of five highly emissive binuclear heteroleptic pyridyltriazole-Cu(i)-phosphine complexes 1-5 was synthesized and examined by different experimental (IR, elemental and thermogravimetric analysis, single crystal X-ray diffraction technique, UV-vis and fluorescence spectroscopy) and quantum chemical aproaches. Complexes 1-5 exhibited excellent stimuli-responsive photoluminescent performance in the solid state at room temperature (quantum yield (QY) = 27.5-52.0%; lifetime (tau) = 8.3-10.7 mu s) and when the temperature was lowered to 77 K (QY = 38.3-88.2; tau = 17.8-134.7 mu s). The highest QY was examined for complex 3 (52%) that can be explained by the small structural changes between the ground S-0 and exited S-1 and T-1 states leading to the small S-1-T-1 triplet gap and efficient thermally-activated delayed fluorescence. Moreover, complex 4 demonstrates reversible mechanochromic and excitation dependent luminescence.
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| 6. |
- Gusev, Alexey, et al.
(författare)
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Structure and excitation-dependent emission of novel zinc complexes with pyridyltriazoles
- 2019
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 9:38, s. 22143-22152
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Tidskriftsartikel (refereegranskat)abstract
- A series of Zn(ii) complexes with 5-(4-R-phenyl)-3-(pyridin-2-yl)-1,2,4-triazoles have been synthesized and subsequently characterized by single crystal X-ray diffraction, H-1-NMR, FT-IR spectroscopy, elemental analyses, ESI-MS, and PXRD. The X-ray diffraction analyses revealed that the complexes have a similar molecular structure and their supramolecular frameworks are constructed by hydrogen bonds and pi center dot center dot center dot pi interaction scaffolds. Upon irradiation with UV light, the studied complexes display deep blue emission at 396-436 nm in the solid state. The compounds show an unexpected excitation-dependent emission phenomenon which is detected by a change in the emission color (from blue to yellow) upon increase of the excitation wavelength. The conducted quantum-chemical calculations indicate that supramolecular differences in the single-crystal architecture of the synthesized complexes play a crucial role for this photophysical behaviour.
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| 7. |
- Gusev, Alexey, et al.
(författare)
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Structure and tuneable luminescence in polymeric zinc compounds based on 3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole
- 2020
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- Inorganic-organic hybrid polymers based on 3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4-Hbpt) ligand were synthesized and subsequently characterized by single-crystal X-ray diffraction, FT-IR spectra, elemental analyses, thermogravimetric (TG) analyses and PXRD. The X-ray diffraction analyses revealed that the complexes [Zn(3,4-Hbpt)Cl-2] and [Zn(3,4-Hbpt)Br-2] possess a 1-D helical chain structure constructed of the 3,4-Hbpt ligands connecting the zinc cations. The [Zn(3,4-bpt)(OAc)] complex demonstrates a 2D sheet structure bridged by tridentate 3,4-bpt-anions. All compounds exhibit substantial thermal stability and show photo-fluorescent properties that result from the ligand pi-pi* transition. Ultraviolet-to-visible tunable emission for two of the complexes is observed.
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| 8. |
- Gusev, Alexey, et al.
(författare)
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Structure-induced luminescence and bioactivities of Zinc(II) complexes with 2-(2,4-dichlorophenoxy)-N?-[pyridin-2-ylmethylene]acetohydrazide
- 2023
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Ingår i: Inorganica Chimica Acta. - : ELSEVIER SCIENCE SA. - 0020-1693 .- 1873-3255. ; 551
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Tidskriftsartikel (refereegranskat)abstract
- The structure and photophysical properties of the series of Zn(II) complex with the hydrazone ligand, 2-(2,4dichlorophenoxy)-N -[1-pyridin-2-ylmethylene]acetohydrazide, and different counter anions have been synthesized and characterized by single crystal X-ray diffraction, FT-IR, elemental analyses and ESI-MS. X-ray crystallography has proved the neutral or monoanionic form of ligand upon coordination. All complexes are mononuclear with the tetra/penta/hexacoordinated zinc atoms. The diverse supramolecular architectures of the complexes show that counter-anions have significant impacts on the structures. Furthermore DFT, luminescence properties, antibacterial and herbicide activities of the complexes have been investigated were carried out as well.
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| 9. |
- Lunder Halvorsen, Helene, et al.
(författare)
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Spatial variability and temporal changes of POPs in European background air
- 2023
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 299
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Tidskriftsartikel (refereegranskat)abstract
- Concentration data on POPs in air is necessary to assess the effectiveness of international regulations aiming to reduce the emissions of persistent organic pollutants (POPs) into the environment. POPs in European background air are continuously monitored using active- and passive air sampling techniques at a limited number of atmospheric monitoring stations. As a result of the low spatial resolution of such continuous monitoring, there is limited understanding of the main sources controlling the atmospheric burdens of POPs across Europe. The key objectives of this study were to measure the spatial and temporal variability of concentrations of POPs in background air with a high spatial resolution (n = 101) across 33 countries within Europe, and to use observations and models in concert to assess if the measured concentrations are mainly governed by secondary emissions or continuing primary emissions. Hexachlorobenzene (HCB) was not only the POP detected in highest concentrations (median: 67 pg/m3), but also the only POP that had significantly increased over the last decade. HCB was also the only POP that was positively correlated to latitude. For the other targeted POPs, the highest concentrations were observed in the southern part of Europe, and a declining temporal trend was observed. Spatial differences in temporal changes were observed. For example, γ-HCH (hexachlorocyclohexane) had the largest decrease in the south of Europe, while α-HCH had declined the most in central-east Europe. High occurrence of degradation products of the organochlorine pesticides and isomeric ratios indicated past usage. Model predictions of PCB-153 (2,2’,4,4’,5,5’-hexachlorobiphenyl) by the Global EMEP Multi-media Modelling System suggest that secondary emissions are more important than primary emissions in controlling atmospheric burdens, and that the relative importance of primary emissions are more influential in southern Europe compared to northern Europe. Our study highlights the major advantages of combining high spatial resolution observations with mechanistic modelling approaches to provide insights on the relative importance of primary- and secondary emission sources in Europe. Such knowledge is considered vital for policy makers aiming to assess the potential for further emission reduction strategies of legacy POPs.
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