Theoretical Study of the Effect of Substituting Nitrogen Atom in Tetracyanoquinodimethane (TCNQ), Using Density Functional Theory

The optimized geometrical structures and the electronic properties of theTetracyanoquinodimethane molecule (TCNQ) and its derivative have been calculated using density functional theory with (B3LYP) and 6-31G** level. The aim of this work is to determine the effects of substituting the nitrogen atom in mentioned molecule with trivalent atoms(phosphorus P and arsenic As). The results show that the both HOMO and LUMO energydecrease whenever the trivalent atom substitute instead of nitrogen atom. The energy gap decrease when replace nitrogen atom with trivalent atom. With respect to electron affinity then any nitrogen atom has been replaced with trivalent atom, the formed molecule will has more pos itive electron affinity, this new molecule will be a good electron acceptor.