Solvent effect on an electron-transfer reaction of pyridinyl radicals

Abstract

an enormous solvent effect on the rate of the reaction.Not only is the solvent effect on the reaction of 1 with 4-nitrobenzyl chloride large, but the change in rate constant for the change in solvent from 2-methyltetrahydrofuran to acetonitrile is on the order of that expected for a reaction in which an ion pair is created from a pair of neutral molecules. The fundamental process to which we can refer is that for the solvent polarity standard, Z value (the destruction of an ion pair through charge transfer, eq 2).2 The operation COOCH3

Synthesis and Supramolecular Properties of Molecular Clips with Anthracene Sidewalls

“…In the case of TNF complexes 17@1 a, 17@1 b, and 17@1 c the color again changes from yellow to green due to intense CT bands, this time at l max = 677-689 nm ( Table 3). The complex of 1 c with the solvatochromic Kosower salt 18 (frequently applied as a probe of solvent polarity) [40][41][42][43][44][45] does not show a significant change in color relative to pure 18 dissolved in CHCl 3 . In the UV/Vis spectrum of a mixture of 1 c (c 0 = 2.2 10 À4 m) and KS (18) À5 m) and 18 (c 0 = 5.9 10 À5 m), however, the shape and position of the band at the longest wavelength assigned to 18 are substantially changed.…”

Solvent-sensitive charge-transfer absorption behaviours and dual-emissive fluorescent properties of a thiazole-conjugated pyridinium complex

“…1,8,18 Recently, we reported a highly luminescent fluorophore, N-[2-(1 0 ,3 0 ,4,4 0 ,5 0 ,5 0 -hexafluorocyclopentenyl)]-4-(5-methoxythiazolyl)pyridine (4-MePF), in which the interactions between the pyridinium p cation and allyl-type anion, conjugated through a covalent bond, contribute significantly to its spectral properties. 19 Until now, much of the work concerning anion-p interactions has been focused on the effect of solvent on iodide anion-p interactions, [20][21][22][23] with less studies on bromide anion-p interactions. 24 Compared with iodine, bromine exhibits a larger electronegativity and a smaller anionic radius, which performs differently in anion-p interactions.…”

Solvent scales used to study the intermolecular interactions in binary solutions of two p-aryl-pyridazinium methylids

“…There are single parameter scales (Z scale of Kosower [1][2][3][4][5][6], E T (30) scale Dimroth and Reichardt [7], S 0 scale of Drago [8]) and multiparameter scales (p ⁄ , a, b scale of Kamlet and Taft [9], SPP, SA and SB scale of Catalan et al [10,11]). …”