Intra-ring proton transfer effect on the Structure-NLO property relationships of phthalocyanine derivatives

Abstract

Based on the phthalocyanine, four models (1–4) are designed to explore the intra-ring proton transfer effect on structure–property relationships. The results show that small differences in structure bring fascinating changes in nucleus-independent chemical shifts (NICS) values, anisotropy of the induced current density (AICD), natural population analysis (NPA) charge, electrostatic potential (ESP), UV–vis absorption spectrum as well as unit sphere representation (USR). Significantly, the largest static first hyperpolarizability βtot value (1.47 × 104) of 4 is approximately 15 times larger than that (8.98 × 102 au) of 1 due to the intra-ring proton transfer regulating conjugation degree of the conjugation section. Furthermore, the dynamic first hyperpolarizability βHRS at the wavelengths λ = 1907, 1460 nm is elaborated in detail. We hope that the present work may evoke the possibility to probe into a promising field for nonlinear optics (NLO) application.