Hydrogen bonding interactions, semi-empirical quantum chemical calculations and the antibacterial activity in a zwitter-ion derive: 2-[(2-hydroxyphenyl) - iminomethyl] phenyl

The zwitter-ion derivative, 2-[(2-hydroxyphenyl) -iminomethyl] phenyl (2HPIMP), C₁₁ H₁₃ NO₂ has two independent molecules per asymmetric unit with almost similar conformation and mutual orthogonal orientations [dihedral angle = 83.77(4)°]. The conformational difference between geometrically optimized structure from semi-empirical method and the experimental structure demonstrated that, the short intra H…H contacts, intra and intermolecular hydrogen bonds are instrumental in stabilizing the structure in the solid state. The intermolecular charge transfer interaction due to an electron transition from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) caused a cloud of charges to move from the atoms of one molecule to another. The molecule exhibited an effective antibacterial activity against S. aureus and moderate action against E. coli and S. Pyogenus as compared to a standard reference drug, Ampicillin