A comparative DFT study of tetracyanoquinodimethane and its difluoro and tetrafluoro analogs

The optimized molecular structures, harmonic vibrational wavenumbers and corresponding vibrational assignments, frontier molecular orbitals and UV data of 7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane were computed using quantum mechanical code. Calculations were carried out at Becke-3-Lee-Yang-Parr (B3LYP) functional with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) using the 6-311++G (d,p) basis set. The theoretical results were successfully compared with some of the available experimental data. The influence of fluorine on the structural, vibrational and electronic properties were investigated. The addition of fluorine reduces both the electrical and optical band gaps. The findings of this research can be useful for analogs of the molecules studied which have potential applications in the design of organic semiconductors for electronic devise applications.