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

Abstract

Three novel phosphoramidate ligands with formula RP ( O ) R 2 ′ , R = Nicotinamide(nia), R′ = NHC(CH 3) 3( L 1 ), NH(C 6H 11) ( L 2 ); R = isonicotinamide(iso), NH(C 6H 11) ( L 3 ) and their new organotin(IV) complexes with formula SnCl 2(CH 3) 2(X) 2, X = L 1 ( C 1 ), L 2 ( C 2 ) , L 3 ( C 3 ) plus SnCl 2(CH 3) 2(L 4) 2( C 4 ), L 4 = isoP(O)[NHC(CH 3) 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 SnCl 2(CH 3) 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···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.