Diplatinum complexes: Chemoselective reactions of the l-orthometalated, metal-metal bonded complex [Pt_2(μ-o-C_6H_4PPh_2)(μ-PPh_2)(PPh_3)_2] with acids. Crystal structures of [Pt_2Cl(μ-PPh_2)(PPh_3)_3], [Pt_2I(μ-PPh_2)(PPh_3)_3], [Pt_2(μ-H)(μ-PPh_2)I_2(PPh_3)_2] and cis,cis-[Pt_2(μ-I)(μ-PPh_2)I_2(PPh_3)_2]

摘要

In order to investigate further the chemoselectivity of reactions involving the l-orthometalated, metal- metal bonded dinuclear Pt(I) complex [Pt_2(μ-o-C_6H_4PPh_2)(μ-PPh_2)(PPh_3)_2](Pt-Pt) (1), it was reacted with HCl and HI using various stoichiometries. The first step was the breaking of the metal-carbon bond and the formation of C-H and Pt-X bonds. When a 1:1 ratio was used, the complexes [Pt_2X(μ-PPh_2)(PPh_3)_3] (Pt-Pt) (2, X = Cl; 3, X = I) have been obtained but the use of a 2:1 ratio resulted instead in the formation of the complexes [Pt_2(μ-H)(μ-PPh_2)X_2(PPh_3)_2](Pt-Pt) (4, X = Cl; 6, X = I). The latter transformed into [Pt_2(μ-X)(μ-PPh_2)X_2(PPh_3)_2] (5, X = Cl; 7, X = I) in the presence of an additional equivalent of HX. The cis,cis- and cis,trans-isomers of 7 were also obtained by oxidation of 3 with one equivalent of iodine. Whereas compounds 4, cis,cis-5, and cis,trans-7 have been characterized in solution, the complexes 2-1/2C_7H8, 3, 6 and cis,cis-7 have been isolated and structurally characterized by X-ray diffraction.