Synthesis of amidine complexes by metal-mediated addition of amino acid esters to coordinated nitriles

The reaction of the nitrile platinum(IV) complex trans-[PtCl4(EtCN)2] with amino acid esters H2NC(R1)(R2)CO2Me (R1 = R2 = H, H-Me, Me-Me, H-Ph) and H2NCH2CH2CO2Me in CH2Cl2 produces the amidine complexes trans-[PtCl4{ Z-NH=C(Et)NHC(R1)(R2)CO2Me}2] and trans-[PtCl4{ Z-NH=C(Et)NHCH2CH2CO2Me}2], which were isolated in 70–80% yields and characterized by elemental analysis, mass spectrometry, IR spectroscopy, and 1H and 13C{1H} NMR spectroscopy. The structures of the complexes with R1 = R2 = H (1), R1 = H, R2 = Me (2), and R1 = H, R2 = Ph (4) were established by X-ray diffraction analysis.