Infrared and ab initio studies of conducting molecules: 2,5-Diamino-3,6-dichloro-1,4-benzoquinone

2,5-Diamino-3,6-dichloro-1,4-benzoquinone has been synthesized by modifying the procedure reported in literature. Its IR spectrum has been recorded in the solid phase in the range 4000–400 cm−1. Ab initio calculations have been performed using Gaussian ’03 program to compute optimized geometry, harmonic vibrational frequencies along with intensities in IR and Raman spectra and atomic charges at RHF/6-31+G*, B3LYP/6-31+G* and B3LYP/6-311++G** levels. To make vibrational analysis Gaussian View software was used. The optimized molecular structure is found to possess C2h point group symmetry. The observed IR frequencies have been assigned to different modes taking C2h molecular symmetry with the help of pictorial view of normal modes. From the magnitude of the observed frequencies corresponding to the NH2 stretching motions an indication of H-bonding is noticed. From geometrical parameters of the molecule it appears that two parallel sets of conjugated strands are formed in this molecule providing a route to conduct charges. The N–H bonds facing towards chlorine atoms are found to be shorter than those facing towards oxygen atoms indicating the presence of H-bonding between hydrogen atom of an NH2 group and carbonyl (quinoid) oxygen atom.