Synthesis and characterization of complexes of the type [Pt(amine) 4]I 2 and trans-[Pt(CH 3NH 2) 2(H 3C [sbnd]N [dbnd]C(CH 3) 2) 2]I 2 by crystallography and multinuclear magnetic resonance spectroscopy

Abstract

Complexes of the type [Pt(amine) 4]I 2 were synthesized and characterized mainly by multinuclear ( 195Pt, 1H and 13C) magnetic resonance spectroscopy. The compounds were prepared with different primary amines, but not with bulky amines, due to steric hindrance. In 195Pt NMR, the signals were observed between −2715 and −2769 ppm in D 2O. The coupling constant 3 J( 195Pt– 1H) for the MeNH 2 complex is 42 Hz. In 13C NMR, the average values of the coupling constants 2 J( 195Pt– 13C) and 3 J( 195Pt– 13C) are 18 and 30 Hz, respectively. The crystal structure of [Pt(EtNH 2) 4]I 2 was determined by X-ray diffraction methods. The Pt atom is located on an inversion center. The structure is stabilized by H-bonding between the amines and the iodide ions. The compound with n-BuNH 2 was found by crystallographic methods to be [Pt( n-BuNH 2) 4] 2I 3( n-BuNHCOO). The crystal contains two independent [Pt(CH 3NH 2) 4] 2+ cations, three iodide ions and a carbamate ion formed from the reaction of butylamine with CO 2 from the air. When the compound [Pt(CH 3NH 2) 4]I 2 was dissolved in acetone, crystals identified as trans-[Pt(CH 3NH 2) 2(H 3C N C(CH 3) 2) 2]I 2 were isolated and characterized by crystallographic methods. Two trans bonded MeNH 2 ligands had reacted with acetone to produce the two N-bonded Schiff base Pt(II) compound.