Synthesis, characterization, crystal structures, QSAR study and antibacterial activities of organotin bisphosphoramidates

Organotin complexes of bisphosphoramidates were prepared by the reaction of (SnRRRCl)-R-1-R-2-Cl-3 (where R = alkyl/aryl/Cl) and Ph2P(O)XP(O)Ph-2 ligands (where X = diamine). All the compounds were characterized by NMR and IR spectroscopy. X-Ray crystallography confirms that the bridging ligand produces binuclear complexes with SnPh3Cl acceptors in C-a3 and C-a4 and offers a polymeric structure toward SnMe2Cl2 in C-c5. The synthesized compounds were screened for the antibacterial activity against B. cereus and E. coli. Based on the MIC test, the ligands are devoid of antibacterial activity. Notably, among the complexes, triphenyltin adducts exhibited a marked activity only against Gram-positive bacterium B. Cereus (IC50 = 0.78 mu g/mL for C-a3 and C-a5). DFT-QSAR models revealed that the descriptor of the electrophilicity (omega) parameter is correlated with the inhibition activity on B. cereus. The correlation matrix of QSAR models and docking analysis confirmed that the electrophilicity parameter controls the influence of the net charge (Q(Sn)) and polarizability of Sn atom of complexes on the inhibition of B. cereus. (C) 2015 Elsevier B.V. All rights reserved.