Quenching, radical formation, and disproportionation in the photoreduction of 4-carboxybenzophenone by 4-carboxybenzhydrol, hydrazine, and hydrazinium ion
作者:Shai Inbar、Henry Linschitz、Saul G. Cohen
DOI:10.1021/ja00414a047
日期:1981.12
= 6600 M/sup -1/ cm/sup -1/), for CBH, lambda/sub max/ = 570 nm (epsilon = 5500), and for the radical anion CB/sup -/, lambda/sub max/ = 660 nm (epsilon = 8100). The pKa ofCBH was determined, 8.2. Rate constants were determined: for combination of CBH to pinacol, 2k/sub 6/ = 1.8 x 10/sup 9/ M/sup -1/s/sup -1/; for reactions of CBH with CB/sup -/, k/sub 7/ = 1.1 x 10/sup 9/ M/sup -1/s/sup -1/; for disproportionation
已对 4-羧基二苯甲酮 (CB)-4-羧基-二苯甲醇 (CBH/sub 2/) 和 CB-肼系统在 pH 5.8 至 12 范围内进行了激光闪光和稳定照射研究。 与 CBH/sub 反应2/,CB 三重态部分被羧酸盐淬灭,k/sub q/ 约。= 4 x 10/sup 6/ M/sup -1/s/sup -1/;总反应,k/sub 4/ = 3.0 x 10/sup 7/ M/sup -1/s/sup -1/ 导致羰基自由基 CBH,phi = 1.7。记录 CB 三重峰的吸收光谱,λ/sub max/ = 535 nm (epsilon = 6600 M/sup -1/cm/sup -1/),对于 CBH,λ/sub max/ = 570 nm (epsilon = 5500) ,对于自由基阴离子 CB/sup -/,λ/sub max/ = 660 nm (epsilon = 8100)。CBH的pKa被确定为8