The metal-mediated iminoacylation reaction of ketoximes or aldoximes upon treatment with the organonitrile platinum(IV) complexes trans-[PtCl4(RCN)(2)] proceeds under relatively mild conditions in acetonitrile (R = Me) or in chloroform (R = CH2Ph, Ph) to give trans-[PtCl4(NH=C(R)ON=CR1R2)(2)] (R-1 = R-2 = Me; R1R2 = C4H8, R1R2 = C5K10, R1R2 = (H)Ph, R1R2 = (H)C6H4(OH)-o; 1-14) in 90-95% yield. All these-compounds were characterized by elemental analyses (C, H, N, Cl, Pt), FAB mass spectrometry, and IR and H-1, C-13{H-1}, and Pt-195 NMR spectroscopies. X-ray structure determinations of [PtC4(NH=C(Me)ON=CMe2)(2)] (1) and [PtCl4{NH= C(Me)ON=C(C5H10)}(2)] (3) disclosed their overall trans-configuration and the amidine one-end rather than N,N-bidentate coordination made of the N-donor ligands. The iminoacyl species are in E-conformation which is held by a rather weak N-H ... N hydrogen bond between the amidine =NH atom and the oxime nitrogen with the following observed distances and angles for 1 and [3] : N(1)... N(2), and N(1)-H, N(1)H ... N(2) are 2.605 [2.592], 0.74 [0.71], and 2.20 [2.25] Angstrom; N(1)-H ... N(2) is 115 degrees [111 degrees]. No evidence of the Z-conformation in solution was obtained by NMR spectroscopy. Compounds trans-[PtCl4(NH=C(R)ON=CR1R2)(2)] are unexpectedly stable toward hydrolysis both in the solid state and in solutions.