A broadly based investigation of the effects of a diverse array of substituents on the photochemical rearrangement of p-hydroxyphenacyl esters has demonstrated that common substituents such as F, MeO, CN, CO2R, CONH2, and CH3have little effect on the rate and quantum efficiencies for the photo-Favorskii rearrangement and the release of the acid leaving group or on the lifetimes of the reactive triplet state. A decrease in the quantum yields across all substituents was observed for the release and rearrangement when the photolyses were carried out in buffered aqueous media at pHs that exceeded the ground-state pKaof the chromophore where the conjugate base is the predominant form. Otherwise, substituents have only a very modest effect on the photoreaction of these robust chromophores.
一项关于各种取代基对对羟基苯乙酯光化学重排影响的广泛研究表明,常见取代基(如 F、MeO、CN、CO2R、CONH2 和 CH3)对光-Favorskii 重排和酸离去基团释放的速率和量子效率影响很小,对反应三重态的寿命影响也很小。当光解在缓冲水介质中进行时,pH 值超过发色团的基态 pKao(其中共轭碱是主要形式),则释放和重排的量子产率在所有取代基中都会降低。否则,取代基对这些坚固发色团的光反应影响很小。