Addition reactions of primary and secondary aliphatic amines to the benzonitrile ligands in cis- and trans-[PtCl2(NCPh)2] complexes. X-ray structure of the amidine complex trans-[PtCl2{Z-N(H)C(NHBut)Ph}2]

The reactions of cis-[PtCl2(NCPh)2] with a fivefold excess of the primary aliphatic amines RNH2 (R=Me, Et, Pri) in CH2Cl2 at −10 °C afford in high yield the di-amidine complexes cis-[PtCl2{N(H)C(NHR)Ph}2]. The reaction of cis-[PtCl2(NCPh)2] with ButNH2 yields the di-amidine complex trans-[PtCl2{Z-N(H)C(NHBut)Ph}2] which has been characterized also by an X-ray diffraction analysis. The corresponding reactions of trans-[PtCl2(NCPh)2] with a fivefold excess of RNH2 (R=Me, Et) afford the di-amidine derivatives trans-[PtCl2{N(H)C(NHMe)Ph}2], while the reactions of PriNH2 and ButNH2 lead, for the former, to a mixture of the mono-amidine derivative trans-[PtCl2(NCPh){N(H)C(NHPri)Ph}] and the di-amine dicationic species derivative trans-[Pt(PriNH2)2{N(H)C(NHPri)Ph}[Cl]2 and, for the latter, to the mono-amidine complex derivative trans-[PtCl2(NCPh){N(H)C(NHBut)Ph}]. The reactions of cis- or trans-[PtCl2(NCPh)2] di-nitrile complexes with the secondary aliphatic amine Me2NH yields the di-amidine complexes cis- or trans-[PtCl2{N(H)C(NMe2)Ph}2], while the corresponding reactions with RR′NH (R, R′=Me, Et; R=Me, R′=But) produce the mono-amidine complexes cis- or trans-[PtCl2(NCPh){N(H)C(NRR′t)Ph}]. The stereochemistry of the amidine ligands in the final products has been investigated by 1H NMR spectroscopy.