Flash photolysis of the charge-transfer band of 1-methylpyridinium, 1-methylcollidinium, and 1-methylquinolinium iodides

Abstract

The flash photolysis of the charge-transfer band of 1-methylpyridinium and l-methylcollidinium iodide in degassed dichloromethane produced transient absorptions which were attributed to 12'-. Both systems showed permanent loss of parent compound and growth of 13-absorptions. The rate of decay of Iz-from l-methylcollidinium iodide fit second-order kinetics. A M solution of l-methylquinolinium iodide in dichloromethane gave the same second-order transient but appeared to be completely reversible. In deoxygenated acetone the k / e was observed to be ca. lo5 at 6800 A and deoreased with increasing iodide concentration.Solutions of 1-methylquinolinium iodide in l-propanol gave an additional transient absorption at ca. 5300 A

Nanosecond Redox Equilibrium Method for Determining Oxidation Potentials in Organic Media

“…Under these conditions, PhCH 2 SiMe 3 has been shown to react with PhCH 3 +• to produce PhCH 2 SiMe 3 +• , which undergoes rapid fragmentation (<50 ns) to form products that are optically transparent in the visible region of the spectrum . The absorption spectrum recorded 50 ns after the laser pulse (Figure ) shows a long-lived species with λ max ≈ 540 nm, in good agreement with the literature value for NMQ • . The lifetime of NMQ • in dioxygen-saturated CH 2 Cl 2 solution was next measured by transient kinetics.…”

Geometries of donor–acceptor complexes: crystal structures of the iodide, chloride and picrate salts of 1-methylnicotinamide

“…Of the many aromatic acceptors that have been investigated by spectroscopic methods, pyridinium cations have been studied especially extensively (Kosower, 1956;Verhoeven, Dirkx & DeBoer, 1970;Mackay, Landolph & Poziomek, 1971;Kosower & Skorcz, 1960;Mackay & Poziomek, 1972;Cozzens & Gover, 1970;Kosower, 1955;Rembaum, Hadek & Yen, 1971 ;Bradshaw & Deranleau, 1970;Cilento & Tedeschi, 1961;Alivisatos, Ungar, Jibril & Mourkides, 1961;Robbins & Holmes, 1972;Deranleau & Schwyzer, 1970;Cilento & Zinner, 1968;Shifrin, 1965Shifrin, , 1969Kosower, 1960;Shifrin, 1968), usually as iodide chargetransfer complexes (Kosower, 1956;Verhoeven, Dirkx & DeBoer, 1970;Mackay, Landolph & Poziomek, 1971 ;Kosower & Skorcz, 1960;Mackay & Poziomek, 1972;Cozzens & Gover, 1970;Kosower, 1955;Shifrin, 1969). Of the pyridinium cations, particular attention has been given to the acceptor properties of substituted nicotinamide derivatives (Bradshaw & Deranleau, 1970;Cilento & Tedeschi, 1961;Alivisatos, Ungar, Jibril & Mourkides, 1961;Robbins & Holmes, 1972;Deranleau & Schwyzer, 1970;Cilento & Zinner, 1968;Shifrin, 1965Shifrin, , 1969Kosower, 1960;…”

Synthetic Aspects of Photochemical Electron Transfer Reactions

“…Related heterocyclic cation radicals are intermediates in the aromatic hydrocarbon catalyzed, photoelectron transfer reaction of furans. (219) In these cases, 294 ( singlet excited states of various electron-rich arenes, including phenanthrene 299 and naphthalene, activate photoadditions of p-dicyanobenzene and methanol to furans, as illustrated by production of 300 and 301 under these conditions. Several observations are consistent with electron transfer routes through 302 for these processes.…”