含不同质子供体的2-苯基苯并三唑衍生物激发态质子转移的理论研究

Theoretical Study of Excited State Proton Transfer of 2-Phenylbenzotriazole Derivatives with Different Proton Donor

用密度泛函理论(DFT)和二级微扰理论(MP2)研究了带不同质子供体的2-苯基苯并三唑衍生物:2-(2'-羟苯基)苯并三唑(H-TIN),2-(2'-氨苯基)苯并三唑(APyBT)和2-(2'-巯苯基)苯并三唑(MPyBT)的激发态分子内质子转移(ESIPT)性质以及它们作为紫外光吸收剂的光物理机制.结果表明,在基态时三个化合物的最稳定异构体是均存在分子内氢键的正常构型N,而互变异构体T和其扭曲构型Ttwisted都是不稳定的.激发态势能曲线表明H-TIN和APyBT的ESIPT分别需要克服约7.06和20.7 kJ/mol的能垒,而MPyBT的ESIPT无需能垒;同时结合分子轨道,电荷差分密度三维立体图的分析结果表明三个化合物都能发生ESIPT,并且伴随有扭曲分子内电荷转移,这些原因均表明它们都具有好的紫外光稳定作用.

A theoretical study of excited state intramolecular proton transfer（ESIPT） and the photophysical mechanism of UV absorbers of 2-phenylbenzotriazole derivatives with different proton donor： 2-（2＇-hydroxyphenyl）benzotriazole（H-TIN）,2-（2＇-aminophenyl）benzotriazole（APyBT） and 2-（2＇-Mercaptophenyl）benzotriazole（MPyBT） have been performed by density functional theory（DFT） and second order M？ller-Plesset perturbation theory（MP2）.The results show that the most stable tautomer is normal configuration N which has intramolecular hydrogen bond for different tautomers of three compounds in ground state,while the tautomer T and twisted configuration Ttwisted are unstable in ground state.The po-tential energy curves for ESIPT of three compounds show that H-TIN and APyBT can occurs ESIPT that overcome the energy barrier of ca.7.06 and 20.7 kJ/mol,respectively,however the ESIPT of MPyBT can occur without a barrier;meanwhile combined the results of molecular orbital and charge difference density three-dimensional cube for the three compounds,it indicates that H-TIN,APyBT and MPyBT can occur the fast ESIPT and twisted intramolecular charge transfer,these reasons show that they all have good UV stabi-lization.