Structural elucidation, Hirshfeld surface analysis and quantum mechanical study of para-nitro benzylidene methyl arjunolate

A benzylidene derivative of arjunolic acid, namely, para-nitro benzylidene methyl arjunolate (3) have been synthesized and characterized by X-ray structural studies and the electronic structure was calculated at the DFT level with a detailed analysis of Hirshfeld surface and fingerprint plot facilitating a comparison of intermolecular interactions. The crystal packing of (3) exhibits intermolecular O-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds forming linear chains propagating parallel to [1 0 0] and [0 1 0] directions, respectively, which are further linked through C-H center dot center dot center dot pi (arene) bonds to generate two-dimensional framework. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that more than two-thirds of the close contacts are associated with weak interactions. Hirshfeld surface analysis for visually analyzing intermolecular interactions in crystal structures employing molecular surface contours and 2D fingerprint plots have been used to examine molecular shapes. The large HOMO-LUMO energy gap indicates a high kinetic stability for the title compound (3). (C) 2011 Elsevier B.V. All rights reserved.