Calculations on the electronic structure and nonlinear second-order susceptibilities of fulleropyrrolidine–tetrathiafulvalene(C60PY–TTF) based on donor–bridge–acceptor dyads

Abstract

The semiempirical INDO calculations were carried out to investigate the charge-transfer interaction and to evaluate the second-order nonlinear susceptibilities for a series of fulleropyrrolidine–tetrathiafulvalene(C60PY–TTF) dyads, C60PY, and C60PY-(CH=CH)n-TTF (n = 0–6). The equilibrium geometries, electronic structures, and UV–vis spectra of these C60PY–TTFs D–B–A dyads were determined by using ZINDO methods. On the basis of electronic spectra, we calculated the β for the dyads using the ZINDO-SOS expression, and found that these dyads have relatively large β. The calculated values of β are 48.78, 62.34, 97.90, 123.24, 183.78, 189.43, 193.45, 195.82 × 10–30 esu for C60PY and C60PY-(CH=CH)n-TTF (n = 0–6), respectively, which shows the enhancing effect when TTF is introduced. The β significantly increases as n increases from 0–3; and it tends to be saturated in the end.Key words: ZINDO-SOS, CI, structure, spectra, C60PY–TTF.