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131.
Liwu Zhang Hanan H. Mohamed Ralf Dillert Detlef Bahnemann 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2012,13(4):263-276
Charge carrier transfer processes are very important and play a vital role in photocatalytic reactions. A fundamental understanding of the kinetics and mechanisms of these charge transfer processes is crucial from the viewpoint of developing efficient photocatalysis systems for large-scale industrialization. In this work, recent efforts concerning the understanding of the kinetics and the mechanisms of the charge transfer in photocatalytic processes have been reviewed. Fundamental aspects involved in these charge transfer processes, such as charge generation, charge trapping, charge recombination, and electron and hole transfer are primarily discussed. Moreover, some recent studies focusing on enhancing the photocatalytic efficiency by improving the charge transfer and separation are also reviewed. 相似文献
132.
133.
Bakr F. Abdel‐Wahab Hanan A. Mohamed Rizk E. Khidre Mohamed F. El‐Mansy 《Journal of heterocyclic chemistry》2014,51(5):1215-1232
Published data on the methods of preparation of different azoles linked directly to oxadiazoles are described systematically. This review is divided into classes based on the number of heteroatoms in the azoles connected to oxadiazole ring, and the subtitles are divided according to the type of oxadiazoles isomer. 相似文献
134.
Tatiana Dyblenko Andrei Chtchemelinine Ryan Reiter Ruhul Q. Chowdhury Alexander Enaya Hanan Afifi Rene Fournier Gabriela Mladenova Alfred Barry P. Lever Edward Lee‐Ruff 《Photochemistry and photobiology》2014,90(2):470-475
A series of 9‐substituted fluorenols and 9,9′‐disubstituted‐9,9′‐bifluorenyls were irradiated to give products derived from fluorenyl radicals. Product distribution was solvent dependent. A TEMPO adduct was isolated from the photoexcitation of 9‐fluorenol. An unusual unsymmetrical 3,9′‐bifluorenyl was observed from the photolysis of 9‐trifluoromethylfluorenol and 9,9′‐di(trifluoromethyl)‐9,9′‐bifluorenyl in more polar or hydrogen‐bonding solvents. The electronic nature of 9‐substituted fluorenyl radicals was probed using theoretical calculations showing the dipolar character of species with electron‐deficient groups. These constitute the first examples of “doubly destabilized” radicals. 相似文献
135.
Efficient and convenient synthesis of coumarin derivatives was accomplished via reactions of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide with some carbon electrophiles, e.g. maleic anhydride, dimethyl acetylenedicarboxylate, 1,2-dichloroethane, 3′-nitro-w-bromoacetophenone, N-(4-acetylphenyl)-2-chloroacetamide, ethyl cyanoacetate/3-chlorobenzaldehyde and acetylacetone to construct some N-heterocycles such as thiazolidine, thiazole, pyrimidine and pyrazolone derivatives. The structures of all synthesized products were substantiated from their analytical and spectral data. The antioxidant activities of the synthesized compounds were examined. 相似文献
136.
A facile and highly efficient protocol for the synthesis of 1,8-dioxo-octahydroxanthene derivatives was achieved through cascade Knoevenagel-Michael condensations and cyclo-dehydration reaction utilizing tetrachlorosilane(TCS) as catalyst under mild conditions.Reaction of the titled compounds with TCSNaN3 to give novel functionalized pyrano[3,2-c]tetrazolo[1,5-a]azepine derivatives is also described. 相似文献
137.
138.
Anne‐Catherine Bédard Anna Vlassova Augusto C. Hernandez‐Perez André Bessette Prof. Dr. Garry S. Hanan Matthew A. Heuft Prof. Dr. Shawn K. Collins 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16295-16302
Synthesis of helically chiral aromatics resulting from fusion of pyrene and [4]‐ or [5]helicene has been accomplished using photoredox catalysis employing a Cu‐based sensitizer as the key step. Photocyclisation experiments for the synthesis of the target compounds were carried out in batch and using continuous flow strategies. The solid‐state structures, UV/Vis absorption spectra and fluorescence spectra of the pyrene–helicene hybrids were investigated and compared to that of the parent [5]helicene to discern the effects of merging a pyrene moiety within a helicene skeleton. The studies demonstrated that pyrene–helicene hybrids adopt co‐planar or stacked arrangements in the solid state, in contrast to the solid‐state structure of the parent [5]helicene. The UV/Vis and fluorescence spectra of the pyrene–helicene hybrids exhibited strong red‐shifts when compared to the parent [5]helicene. DFT calculations suggest that the strategy of extending the π surface in the y axis of the helicenes increased their HOMO levels while also decreasing their LUMO levels, resulting in significantly reduced band gaps. 相似文献
139.
Ludwig Chenneberg Janaina G. Ferreira Garry S. Hanan 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(4):m81-m84
The title compound, [4′‐(4‐bromophenyl)‐2,2′:6′,2′′‐terpyridine]chlorido(trifluoromethanesulfonato)copper(II), [Cu(CF3O3S)Cl(C21H14BrN3)], is a new copper complex containing a polypyridyl‐based ligand. The CuII centre is five‐coordinated in a square‐pyramidal manner by one substituted 2,2′:6′,2′′‐terpyridine ligand, one chloride ligand and a coordinated trifluoromethanesulfonate anion. The Cu—N bond lengths differ by 0.1 Å for the peripheral and central pyridine rings [2.032 (2) (mean) and 1.9345 (15) Å, respectively]. The presence of the trifluoromethanesulfonate anion coordinated to the metal centre allows Br...F halogen–halogen interactions, giving rise to the formation of a dimer about an inversion centre. This work also demonstrates that the rigidity of the ligand allows the formation of other types of nonclassical interactions (C—H...Cl and C—H...O), yielding a three‐dimensional network. 相似文献
140.
Nag S Ferreira JG Chenneberg L Ducharme PD Hanan GS La Ganga G Serroni S Campagna S 《Inorganic chemistry》2011,50(1):7-9
Two new bidentate ligands (1 and 2) with bicyclic guanidine moieties were synthesized and attached to a Ru(II)(bpy)(2) core (bpy = 2,2'-bipyridine) to afford complexes 3 and 4, which were characterized by spectroscopic and electrochemical methods. Complex 4 was further characterized by X-ray crystallography. In cyclic voltammetric studies, both complexes show a Ru(II/III) couple, which is 500 mV less positive than the Ru(II/III) couple of Ru(bpy)(3)(2+). The (1)MLCT and (3)MLCT states of 3 (560 nm/745 nm) and 4 (550 nm/740 nm) are significantly red-shifted with respect to Ru(bpy)(3)(2+) (440 nm/620 nm). Compounds 3 and 4 exhibit emission from a Ru(II)-to-bpy (3)MLCT state, which is rarely the emitting state at λ > 700 nm in [Ru(bpy)(2)(N-N)](2+) complexes. 相似文献