Synthesis and study of Pt(II)-aromatic amines complexes of the types cis- and trans-Pt(amine) 2(NO 3) 2 and cis-Pt(amine) 2(R(COO) 2)

Abstract

Complexes of the types cis- and trans-Pt(amine) 2(NO 3) 2 with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear magnetic resonance spectroscopies. The cis complexes could be synthesized pure only with the amines of the type Ph–R–NH 2 (R = alkyl), while pure trans compounds were synthesized with all the studied amines. In 195Pt NMR spectroscopy, the dinitrato complexes of the amines Ph–R–NH 2 were observed around −1700 ppm for the cis isomers and at about −1580 for the trans complexes. For the other amines, where a phenyl ring is directly attached to the amino group, the signals were observed at lower fields, −1528 ppm for cis-Pt(PhNH 2)(NO 3) 2 and around −1450 ppm for all the trans isomers. There is a linear relationship between the δ(Pt) of the Pt(amine) 2(NO 3) 2 complexes and the p K a of the protonated amines. The coupling constants 2 J( 195Pt– 1HN) are larger in the cis compounds (ave. 76 Hz) than in the trans isomers (ave. 63 Hz). The complexes cis-Pt(amine) 2(R(COO) 2) with bidentate dicarboxylato ligands were also synthesized and characterized mainly by IR spectroscopy. The compounds apparently decompose in DMF and are too insoluble in other solvents for solution studies.