Synthesis, spectroscopic, and theoretical studies of tin(II) complexes with biologically active Schiff bases derived from amino acids

New tin(II) complexes of general stoichiometry [Sn(L)(2)] with bidentate ligand, derived from amino acids with isatin, 5-chloroisatin have been synthesized. It is characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (H-1, C-13, and Sn-119 NMR) spectroscopic studies. The ligands act as bidentate towards metal ions, via the azomethine nitrogen and deprotonated oxygen of the respective ligands. The bond length, bond angles, highest occupied molecular orbital, lowest unoccupied molecular orbital, chemical hardness, global softness, and the lowest energy model structure of the complexes have been determined by density functional theory (DFT) calculations at B3LYP/LanL2DZ level. A few representative ligands and their tin complexes have been screened for their antibacterial activities and found to be active in this respect.