Dual fluorescence of 2-(2'-pyridyl)benzimidazole in aqueous solution due to photoinduced proton-transfer processes

1990 ◽  
Vol 94 (23) ◽  
pp. 8536-8542 ◽  
Author(s):  
Flor. Rodriguez Prieto ◽  
Manuel. Mosquera ◽  
Mercedes. Novo
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Dual Fluorescence ◽  
Transfer Processes ◽  
Photoinduced Proton Transfer

scholarly journals Aqueous Solution Effects on the Proton-Transfer Processes of GC and AT Base Pairs

2014 ◽  
Vol 30 (2) ◽  
pp. 257-264
Author(s):  
WU Ying-Xi ◽  
◽  
WANG Hong-Yan ◽  
LIN Yue-Xia
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Base Pairs ◽  
Transfer Processes

Effects of Crystal Packing on Photoinduced Proton-Transfer Processes of 2,4-Dinitrobenzylpyridine Derivatives

1997 ◽  
Vol 53 (2) ◽  
pp. 306-316 ◽  
Author(s):  
S. Khatib ◽  
M. Botoshansky ◽  
Y. Eichen
Keyword(s):  
Proton Transfer ◽  
Crystal Packing ◽  
Aromatic Rings ◽  
Proton Abstraction ◽  
Thermally Activated ◽  
Transfer Processes ◽  
Highly Sensitive ◽  
Photoinduced Proton Transfer ◽  
Photochemical Properties

Photoinduced and thermally activated proton-transfer processes taking place in crystals of 2-(2,4-dinitrobenzyl)pyridine and some of its derivatives are highly sensitive to molecular packing. Small differences in the way the molecules are packed in the crystal are found to dominate molecular properties in controlling the photoactivity of the different phototautomers, leading, for example, to photoactive or photoinert systems. Three compounds, 2-(2,4-dinitrobenzyl)-4-methylpyridine, 1-(2,4-dinitrophenyl)-l-(2-pyridine)ethane and 4′-(2,4-dinitrobenzyl)-4-methyl-2,2′-bipyridine, having different photochemical properties, were prepared and their crystal structures characterized by means of X-ray analysis. In the photoinert crystals the 2,4-dinitrophenyl group is π-stacked with other aromatic rings of neighboring molecules. This arrangement may open some deactivation channels to the excited state which are faster than the proton-transfer process, leading to photoinert crystals. The absence of π-stacking between the chromophore and other aromatic rings leads to photoactive systems. An O atom of the o-nitro group is the only basic atom that is systematically found to interact with the abstracted proton. It seems that this atom is responsible for the photoinduced proton abstraction of the benzylic H atom, while the role of the N atom of the pyridine ring in the proton-abstraction process is mainly inductive.

Long-lived photoinduced proton transfer processes

1995 ◽  
pp. 713 ◽  
Author(s):  
Yoav Eichen ◽  
Jean-Marie Lehn ◽  
Michael Scherl ◽  
Dietrich Haarer ◽  
Roger Casalegno ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Transfer Processes ◽  
Photoinduced Proton Transfer

scholarly journals Base-enhanced catalytic water oxidation by a carboxylate–bipyridine Ru(II) complex

2015 ◽  
Vol 112 (16) ◽  
pp. 4935-4940 ◽  
Author(s):  
Na Song ◽  
Javier J. Concepcion ◽  
Robert A. Binstead ◽  
Jennifer A. Rudd ◽  
Aaron K. Vannucci ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Proton Transfer ◽  
Water Oxidation ◽  
Proton Acceptor ◽  
Half Time ◽  
X Ray ◽  
X Ray Crystallography ◽  
Buffer Base ◽  
Electron Proton Transfer ◽  
C Nmr

In aqueous solution above pH 2.4 with 4% (vol/vol) CH3CN, the complex [RuII(bda)(isoq)2] (bda is 2,2′-bipyridine-6,6′-dicarboxylate; isoq is isoquinoline) exists as the open-arm chelate, [RuII(CO2-bpy-CO2−)(isoq)2(NCCH3)], as shown by 1H and 13C-NMR, X-ray crystallography, and pH titrations. Rates of water oxidation with the open-arm chelate are remarkably enhanced by added proton acceptor bases, as measured by cyclic voltammetry (CV). In 1.0 M PO43–, the calculated half-time for water oxidation is ∼7 μs. The key to the rate accelerations with added bases is direct involvement of the buffer base in either atom–proton transfer (APT) or concerted electron–proton transfer (EPT) pathways.

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