Reactivity oftrans-[PtX2(ketoxime)2] Complexes towardm-Chloroperoxybenzoic Acid: An Efficient Route to Coordinated Nitrosoalkanes and Solvent Dependence of the Reaction

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Abstract
The platinum(II) compounds trans-[PtX2(RR‘CNOH)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 [PtX2{N(O)CRR‘ONCRR‘}] containing coordinated nitrosoalkane ligands. The complexes [PtX2{N(O)CRR‘ONCRR‘}] were characterized by elemental analysis, EI-MS, IR, electronic absorption, and 1H NMR spectroscopy; X-ray structure analysis was performed for [PtCl2{N(O)CC5H10ONCC5H10}]. The latter compound crystallizes in the triclinic P1̄ space group with a = 9.214(2) Å, b = 9.577(2) Å, c = 10.367(2) Å, α = 109.14(2)°, β = 91.87(2)°, γ = 115.62(2)°, V = 762.8(3) Å3, Z = 2, and ρcalcd = 2.135 g cm-3. The reaction between trans-[PtX2(RR‘CNOH)2] and MCPBA displays a solvent dependence: interaction of these reagents in ketones, R1R2CO, yields the platinum(IV) chelates [PtX2(OCR1R2ONCRR‘)2], while the oxidation state of the oxime N atom remains unchanged. Heating [PtCl2(OCR1R2ONCRR‘)2] in DMF or in DMF-d7 at 100 °C leads to the extrusion of R1R2CO and the formation of [PtCl2{N(O)CRR‘ONCRR‘}].