Photochemistry of αα′-disbstituted azoalkanes. Part II. Photolytic dechlorination, decomposition, and oxidation of αα′-dichloro- and αα′-diacyloxy-azoalkanes

The electrochemical reduction of 1,4-dichloroazoethanes: Reductive elimination of chloride to form aryl azines

“…The theoretical G / = o values are obtained by substituting the results from Eqs. (10)(11)(12) into Eq. (7), which yields 3.1, 3.8 and 6.2 kcal mol −1 by the Marcus (Eq.…”

“…Several approaches exist for estimating o , as shown by Eqs. (10)(11)(12), based on the molecular and solvent parameters (where D op and D s are the optical and static dielectric constants) [24]. These approaches provide reasonable estimates of o when there is negligible contribution from the internal reorganization energy.…”

“…The purity of the 1-X/Y was confirmed by melting point determination and elemental analysis. 1,1 -Dichloro-1,1 -bis(4-nitrophenyl)-1,1 -azoethane (1-NO 2 / NO 2 ): [10] 1, 140.4, 132.4, 128.9, 128.6, 127.3, 126.3, 118.3, 112.7, 94.7, 93 (d, 2H); 13 C NMR (100 MHz, CDCl 3 ): ı C 147. 9,140.4,129.0,128.6,127.7,126.3,123.7,94.7,93.0,30.6,30.1; 138.7,137.9,129.2,128.7,128.5,126.4,126.3,94.5,94.4,30.1,29.9,21.1;: max = 218 nm, ε = 8220 cm −1 M −1 ; elemental analysis, calc.…”

“…In addition to an azo moiety, these compounds also have two reducible benzyl halide groups. In previous photochemical studies of 1,4-dichloroazoethanes, azines (2,3-diaza derivatives of butadienes -C N-N C-) were isolated as products [1,5,10]. The reaction was also found to yield a significant amount of radical coupling and oxygenated products due to the formation of a carbon radical intermediate with loss of molecular nitrogen (Scheme 1) [5,10].…”

“…In previous photochemical studies of 1,4-dichloroazoethanes, azines (2,3-diaza derivatives of butadienes -C N-N C-) were isolated as products [1,5,10]. The reaction was also found to yield a significant amount of radical coupling and oxygenated products due to the formation of a carbon radical intermediate with loss of molecular nitrogen (Scheme 1) [5,10]. Considering that 1,4-dichloroazoethanes exhibit the loss of dinitrogen upon irradiation via cleavage of the C-N bonds, we were interested in examining if under electrochemical conditions a competition would exist between C-Cl versus C-N reductive cleavage, and whether this competition could be controlled by a change in the aryl substituent.…”