Oxidative addition of halogens to a Dineophylplatinum(II) Complex: Halogen complexes and fluxional Platinum(IV) complexes

The reactions of [Pt(CH2CMe2Ph)2(phen *)], 2 , phen* = 3,4,7,8-tetramethyl-1,10-phenanthroline, with halo-gens X 2 or their equivalents [PhICl2 (as a Cl2 equivalent), Br2 and I 2 ] have been studied. The products [PtX(CH2CMe2Ph)(phen*)], 3 , and cis,cis-[PtX2(CH2CMe2Ph)2(phen *)], 4 , were formed in all cases. Remark-ably, the octahedral platinum(IV) complexes 4 were fluxional in solution in CD2Cl2 or CD3OD, as shown by their NMR spectra, and a mechanism involving very rapid reversible halide dissociation as a first step is established. The reaction of complex 2 in ether with PhICl2 also gave an equilibrium mixture of three isomers of [PtCl(CH2CMe2Ph)(CH2CMe2C6H4)(phen*)] by aromatic C -H bond activation. In other solvents, this reaction also gave [PtCl(CH2CMe2Ph)(phen *)] and then [PtCl2(CH2CMe2C6H4)(phen *)] and the C -H bond activation step is shown to occur at the axial site of the platinum(IV) center. The structures of eight complexes are established crystallographically.(c) 2023 Elsevier B.V. All rights reserved.