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 F 2 and the electron density distribution obtained from the multipolar model.

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In the present work the optimized molecular geometry and harmonic vibrational frequencies of chalcone derivative were calculated by DFT/B3LYP method with 6–31G (d,p) basis set. The vibrational assignments were performed on the basis of the potential energy dis-tribution (PED) of the vibrational modes. Natural bond orbital (NBO) analysis has been performed on title compound using B3LYP/6–31G (d,p) and HSEh1PBE /6–31G (d,p) levels in order to elucidate intermolecular hydrogen bonding, intermolecular charge transfer (ICT) and delocalization of electron density. Mulliken atomic charges, natural population analysis (NPA) and atomic polar tensors (APT) were performed. The nonlinear optical properties of the title compound are also calculated and discussed. Molecular electrostatic poten-tial and HOMO-LUMO energy levels are also computed. Ultraviolet–visible spectrum of the title compound has been calculated using TD–DFT method. The molecular orbital contributions were studied by density of states (DOSs). Global reactivity descriptors have been calculated using the HOMO and LUMO to predict compound reactivity.   

Bojar, K.; Green's function and electro-elastic fields in a 2D piezoelectric strip with straight line defects and free boundaries: Fourier approach for bodies of cubic symmetry. Int. J. Sci. Eng., 2010, submitted. [3] Bojar, K.; Green's function and electro-elastic fields in a 2D piezoelectric strip with straight line defects and free boundaries: Fourier approach for bodies of unrestricted anisotropy.

Poster Sessions C515 to extended delocalized π-electron systems and the intrinsic neglect of intermolecular interactions are investigated.