A 3-D Mn(II) complex containing N-isonicotinyl, N′,N′′-bis(hexamethylenyl) phosphoric triamide ligand: synthesis, structural characterization, and thermal studies

A new phosphoryl-containing ligand, N-isonicotinyl, N′,N′′-bis(hexamethylenyl) phosphoric triamide (1), was synthesized and characterized using IR, 1H, 13C, and 31P NMR and UV–vis spectroscopy. Reaction of 1 with MnCl2·4H2O led to the formation of Mn(II) complex with the formula {Mn[4-NC5H4C(O)NHP(O)(NC6H12)2]2Cl2}n (2). Crystal structures of 1 and 2 were determined by X-ray crystallography, which reveals that 2 is centrosymmetric with two phosphoryl oxygens, chloride and nitrogen in trans positions. Coordination of bridged bidentate 1 through oxygen of the phosphoryl and nitrogen of the pyridine afforded a 3-D network extended by coordinative bonds. Compound 2 and its nano-sized particles prepared by sonochemical method were characterized by IR spectroscopy, X-ray powder diffraction, and thermal analysis and exhibited paramagnetic behavior at room temperature. Crystalline mixture of Mn2P2O7 and Mn2P4O12 was identified as a thermolysis product of 2.