New organotin(IV) complexes of nicotinamide, isonicotinamide and some of their novel phosphoric triamide derivatives: Syntheses, spectroscopic study and crystal structures

Three novel phosphoramidate ligands with formula RP(O)R-2', R = Nicotinamide(nia), R' = NHC(CH3)(3)(L-1), NH(C6H11)(L-2); R = isonicotinamide(iso), NH(C6H11) (L-3) and their new organotin(IV) complexes with formula SnCl2(CH3)(2)(X)(2), X = L-1 (C-1), L-2 (C-2), L-3 (C-3) plus SnCl2(CH3)(2)(L-4)(2)(C-4), L-4 = isoP(O)[NHC(CH3)(3)](2), were synthesized and characterized by H-1, C-13, P-31, Sn-119 NMR, IR, UV-Vis spectroscopy and elemental analysis. Two novel complexes of nia and iso with formula SnCl2(CH3)(2)(X)(2), X = nia (C-5), iso (C-6) were also prepared and all the complexes were spectroscopically studied in comparison to their related ligands and to each other. The crystal structure of complexes C-1, C-3, C-4, and C-5 were determined by X-ray crystallography. -Sn-Cl center dot center dot center dot H-N-major hydrogen bonds beside other electrostatic interactions produced a three dimensional polymeric cluster in the crystalline lattice of C-1, C-3, C-5 and a two dimensional polymeric chain in C-4. Results showed that coordination of the phosphoramidate ligand (L-4) to Sn in C-4 has been occurred from the nitrogen site of the pyridine ring similar to C-5, C-6 in which there is no P=O donor site; however, in C-1 and C-3 the active donor site of corresponding ligands is P=O. It seems that in these complexes there is a competition between P=O and N-pyridine donor sites and the influential factor which determines the winner site is the type of substituents on phosphorus atom. (C) 2010 Elsevier B.V. All rights reserved.