The platinum(II) compounds trans-[PtX(2)(RR’C=NOH)(2)] [X = Cl, R = R’ = Me, RR’ = (CH2)(4), (CH2)(5); X = Br, R = R’ = Me] react with m-chloroperoxybenzoic acid (MCPBA) in dimethylformamide to give the platinum(II) complexes [PtX(2){N(=O)CRR’ONCRR’}] containing coordinated nitrosoalkane ligands. The complexes [PtX(2){N(=O)CRR’ONCRR’}] were characterized by elemental analysis, EI-MS, IR, electronic absorption, and H-1 NMR spectroscopy; X-ray structure analysis was performed for [PtCl2{N(=O)CC5H10ONCC5H10}].)]. The latter compound crystallizes in the triclinic space group with a = 9.214(2) Angstrom, b = 9.577(2) Angstrom, c = 10.367(2) Angstrom, alpha = 109.14(2)degrees, beta = 91.87(2)degrees, gamma = 115.62(2)degrees, V = 762.8(3) Angstrom(3), Z = 2, and rho(calcd) = 2.135 g cm(-3). The reaction between trans-[PtX(2)(RR’C=NOH)(2)] and MCPBA displays a solvent dependence : interaction of these reagents in ketones, R(1)R(2)C=O, yields the platinum(IV) chelates [PtX(2)(OCR(1)R(2)ON=CRR’)(2)], while the oxidation state of the oxime N atom remains unchanged. Heating [PtCl2(OCR(1)R(2)ON=CRR’)(2)] in DMF or in DMF-d(7) at 100 degrees C leads to the extrusion of R(1)R(2)C=O and the formation of [PtCl2{N(=O)CRR’ONCRR’}].