Very Efficient Generation of Quinone Methides through Excited State Intramolecular Proton Transfer to a Carbon Atom
作者:Nikola Basarić、Nađa Došlić、Jakov Ivković、Yu-Hsuan Wang、Momir Mališ、Peter Wan
DOI:10.1002/chem.201201144
日期:2012.8.20
deuterium at the ortho‐positions of the adjacent phenyl ring (overall Φ=0.73±0.07), along with minor incorporation at the naphthalene positions 5 and 8. These finding are explained by excited state intramolecular proton transfer (ESIPT) from the phenolic OH group to the corresponding carbon atoms, the main pathway giving rise to quinone methide (QM) 7, which has been characterized by LFP (τ≈20 ns; 460 nm)
在CH 3 CN / D 2 O(3:1)中辐照2-苯基-1-萘酚(6)可将氘非常有效地引入到相邻苯环的邻位(总Φ = 0.73±0.07) ,以及在萘5和8位上的少量掺入。这些发现可以通过激发态分子内质子转移(ESIPT)从酚式OH基团转移到相应的碳原子来解释,主要途径是生成醌甲基化物(QM)7, LFP(τ≈20ns;460 nm)。已使用二阶近似耦合簇(CC2)方法探索了ESIPT反应路径。在非质子溶剂中,从萘酚OH到苯环邻位的ESIPT以1 L的能级面通过S 0状态的圆锥形交点以无障碍的方式进行,传递7。在水性溶剂中,会形成具有H 2 O的团簇,其中质子转移(PT)到溶剂中以及H 2 O介导的中继机制产生了萘甲酸酯和QM。将结果与2-苯基苯酚(3),它还会经历无障碍ESIPT,并通过圆锥形交叉点进行质量管理。但是,由于基态中不利的构象,ESIPT的量子效率为3(D交换的Φ = 0.