Temperature dependent solvent effects have been investigated on the Norrish Type II reaction of 1-phenylpentan-1-one and its p-methyl derivative. Efficiencies of the photoreaction were studied in terms of solvent polarity and base addition as a function of temperature. Such a small structure change as the p-methyl substitution in 1-phenylpentan-1-one altered the temperature dependent photoreactivity in presence of weak bases. The experimental results suggest that the hydrogen bonding between the Type II biradical intermediate OH group and the solvent is weaker for 1-(4-methylphenyl)pentan-1-one than that for 1-phenylpentan-1-one at 20 °C but the interactions probably vanish in both cases at 80 °C.
研究了溶剂效应对1-苯基戊烷-1-酮及其p-甲基衍生物的Norrish II型反应的温度依赖性。通过溶剂极性和添加碱作为温度的函数,研究了光反应效率。1-苯基戊烷-1-酮中如此小的结构变化,即p-甲基取代,在弱碱存在下改变了温度依赖的光反应性。实验结果表明,在20°C时,II型双自由基中间体OH基团与溶剂的氢键对于1-(4-甲基苯基)戊烷-1-酮比1-苯基戊烷-1-酮要弱,但在80°C时,这两种情况下的相互作用可能都会消失。