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)R2′, R = Nicotinamide(nia), R′ = NHC(CH3)3(L1), NH(C6H11) (L2); R = isonicotinamide(iso), NH(C6H11) (L3) and their new organotin(IV) complexes with formula SnCl2(CH3)2(X)2, X = L1 (C1), L2 (C2), L3 (C3) plus SnCl2(CH3)2(L4)2(C4), L4 = isoP(O)[NHC(CH3)3]2, were synthesized and characterized by 1H, 13C, 31P,119Sn NMR, IR, UV–Vis spectroscopy and elemental analysis. Two novel complexes of nia and iso with formula SnCl2(CH3)2(X)2, X = nia (C5), iso (C6) 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 C1, C3, C4, and C5 were determined by X-ray crystallography. –Sn–Cl···H–N– major hydrogen bonds beside other electrostatic interactions produced a three dimensional polymeric cluster in the crystalline lattice of C1, C3, C5 and a two dimensional polymeric chain in C4. Results showed that coordination of the phosphoramidate ligand (L4) to Sn in C4 has been occurred from the nitrogen site of the pyridine ring similar to C5,C6 in which there is no PO donor site; however, in C1 and C3 the active donor site of corresponding ligands is PO. It seems that in these complexes there is a competition between PO and Npyridine donor sites and the influential factor which determines the winner site is the type of substituents on phosphorus atom.

Several novel phosphoramidate ligands and their organotin(IV) complexes were synthesized besides two new Sn(IV) complexes of nicotinamide and isonicotinamide and all were characterized by different spectroscopic techniques. The crystal structure of four complexes was determined by X-ray crystallography. The competition between PO and Npyridine donor sites was studied in these complexes.Figure optionsDownload as PowerPoint slide