Impact of C–H···X (X = F, N) and π–π Interactions on Tuning the Degree of Charge Transfer in F6TNAP-Based Organic Binary Compound Single Crystals

Abstract

Single crystals of four new charge transfer compounds, triphenylene (TP)-1,3,4,5,7,8-hexafluorotetracyanonaphthoquinodimethane (F6TNAP), pyrene-F6TNAP, phenanthrene (PA)-F6TNAP, and naphtho[1,2-b:5,6-b’]dithiophene (NDT)-F6TNAP, with needle-like morphologies and dark color were grown by chemical vapor transport. The influence of C–H···X (X = F, N) interactions as well π–π interactions on the degree of charge transfer (DCT) in these compounds was investigated. The results indicate that the DCT is proportional to the interplanar D–A distance along the π–π interaction direction in TP-F6TNAP, pyrene-F6TNAP, and PA-F6TNAP single crystals. With the decreasing of the D–A interplanar distance from 3.3560 A of TP-F6TNAP to 3.3254 A of PA-F6TNAP, the DCT is significantly increased from 0.03 ± 0.02 of TP-F6TNAP to 0.26 ± 0.03 of PA-F6TNAP, showing the strong relationship between π–π interactions and the DCT. In addition to π–π interactions, a stronger C–H···F interaction (C–H···F bond length: 2.3689 A) is observed i...