Structural and electron charge density studies of a nonlinear optical compound 4,4 di-methyl amino cyano biphenyl

The 4,4 dimethyl amino cyano biphenyl crystal (DMACB) is characterized by its nonlinear activity. The intra molecular charge transfer of this molecule results mainly from the electronic transmission of the electro-acceptor (cyano) and electro-donor (di-methyl-amino) groups. An accurate electron density distribution around the molecule has been calculated based on a high-resolution X-ray diffraction study. The data were collected at 123 K using graphite-monochromated Mo Kα radiation to sin(θ)/λ=1.24 Å^-1. The integrated intensities of 13796 reflections were measured and reduced to 6501 independent reflections with I≥3σ(I). The crystal structure was refined using the experimental model of Hansen and Coppens (1978). The crystal structure has been validated and deposited at the Cambridge Crystallographic Data Centre with the deposition number CCDC 876507. In this article, we present the thermal motion and the structural analysis obtained from the least-square refinement based on F² and the electron density distribution obtained from the multipolar model.