四氮杂环庚烯吡咯衍生物光电性质的理论预测

Theoretical Prediction on Photoelectric Properties for Pyrrole Derivatives of Zoanthoxanthin

运用密度泛函(DFT)与含时密度泛函(TD-DFT)理论方法,研究了荧光母体分子(M0)及其吡咯衍生物(M1~M3)的基态S0和激发态S1的几何结构、前线分子轨道、电离能、电子亲和势、重组能、吸收和荧光光谱.计算确证M0~M3存在稳定且无虚频的S0和S1态,均采取共轭的准平面构型;所有M0~M3分子的S0■S1跃迁均为相应HOMO、LUMO之间π■π*跃迁,且S1态都为明态;在TD-B3LYP (TDPBE0)/6-31+G (d)方法水平上及以甲醇溶剂的极化连续模型下,预测M0~M3最大吸收波长分别为263(257)、380 (374)、500 (496)和542 (543) nm;荧光发射波长分别为465 (455)、555 (545)、621(610)和681 (675) nm;增加吡咯环,能降低电子、空穴重组能而增强空穴、电子的注入能力与传输能力,同时增大了S0■S1电子跃迁的相对振子强度.

In this paper, the geometry structures, frontier molecular orbitals, ionization potential,electron affinity and reorganization energy,together with the absorption and fluorescence spectras of the fluorescent substrate molecule M0 and its pyrrole derivatives(M1~M3) were investigated using time-dependent density functional theory.Optimizations and frequency analyses testified that all S0,S1 states adopted stable conjugated quasi-planar geometries.The results showed that,for M0~M3 molecules,all S0■S1 transitions were assigned to optically allowed π■π* transition between the corresponding HOMO and LUMO, and that all the corresponding S1 states were bright states. At TDB3 LYP(TD-PBE0) levels,applying PCM and CH3 OH solvation models,the predicted maximum absorption wavelengths for M0→M3 were 263(257)、380(374)、500(496) and 542(543) nm,respectively. And the fluorescence wavelengths were 465(455), 555(545), 621(610) and 681(675) nm,respectively.Results also clearly showed that,increasing the pyrrole ring could reduce the hole,electron reorganization energies and enhance both the injection and transport abilities of the hole and electron,and simultaneously increase the relative oscillator strength of S0■S1 electron transition.