Oxidative addition to bis(trifluoromethyl)platinum(II) complexes with N-donor ligands

Reaction of cis-Pt(CF)L (L = pyridine (py); L = 2,2′-bipyridyl (bipy), N,N,N′,N′-tetramethylethylenediamine (tmen)) with halogens, X, in dry CHCl gave initially the isomer of Pt(CF)XL in which the halogen has added trans across the original square plane. The initial products, Pt(CF)X(bipy) (X Cl, Br), slowly isomerize under light to the isomer with the two X-ligands cis, apparently to relieve steric pressure. Cis-Pt(CF)L with L py, 1/2(bipy) (but not that with L = 1/2(tmen)) reacted slowly with alkyl halides, RX (MeI, PhCHBr, CFI), in acetone under light to give Pt(CF)RXL. Only the isomer of Pt(CF)MeI(bipy) with methyl trans to iodide was observed, but for the pyridine analogue two isomeric products were in equilibrium. Pt(CF)MeI(py) also slowly lost MeI in acetone; addition of NaI or py to the solution accelerated the reaction. Pt(CF)(bipy) with PhCHBr gave only the isomer of Pt(CF)-(CHPh)Br(bipy) in which benzyl bromide had added trans across the square plane, but with Pt(CF)py only the isomer of Pt(CF)-(CHPh)Brpy with benzyl cis to bromide was observed. Subsequent reaction in the presence of excess PhCHBr gave, among other products, [PhCHNCH]-[Pt(CF)Brpy]. Fac-Pt(CH)IL was the only significant product from the reactions involving CFI. Aspects of F, C and Pt NMR spectra, and IR spectra, are discussed