双氮桥联1,10-菲咯啉大环化合物分子构型的从头算研究

Ab initio Calculation Investigation on the Molecular Conformation of Aza-bridged Bis-phenanthroline Macrocyclic Compound

应用规范不变原子轨道法 (GIAO)在 RHF/ 6 -31 G* *和 B3LYP/ 6 -31 G* *水平上计算了质子化双氮桥联 1 ,1 0 -菲咯啉大环化合物 (H4HAPP2 +) D2 h和 C2 h构型的 1 H NMR,并用 TDDFT法计算了 H4HAPP2 +电子光谱 .结果表明 ,B3LYP/ 6 -31 G*优化的 C2 h构型为较优构型 ,经谐振频率验证无虚频 ,C2 h构型是H4HAPP2 +合理的对称性构型 .

The 1H NMR chemical shifts of aza-bridged bis-phenanthroline macrocycle(H 2HAPP) in d-TFA solvent, with D 2h and C 2h symmetric conformation, have been calculated at RHF/6-31G ** and B3LYP/6-31G ** level by using ab initio GIAO method. The calculated chemical shifts of protonized H 4HAPP 2+ species with C 2h symmetric conformation are in good agreement with the experimental data, and the C 2h symmetric conformation optimized at B3LYP/6-31G * level is preferable. The calculated results of the harmonic vibration frequency of C 2h and D 2h geometries optimized at B3LYP/6-31G * level indicate that C 2h conformation is stable and D 2h is not stable. The electronic spectrum of protonized species H 4HAPP 2+ has also been calculated by using ab initio TDDFT method. Theoretical investigation suggests the protonized species H 4HAPP 2+ is of C 2h symmetry.