NOVEL ASPECTS OF ETA'-DIIODINE COORDINATION AND DIIODINE OXIDATIVE ADDITION TO PLATINUM(II) AND HALIDE TRANSFER OXIDATION REACTIONS OF ORGANO-PLATINUM(II) WITH CUIIX2

Reactions of mono- and bis-orthochelated diorganoplatinum(II) species [Pt(l-naphthyl-8-NMe2)2l» [Pt(C6H4{CH2NMe2l-2)2], and [Pt(R)(C6H3{CH2NMe2} 2-2,6)] with the electrophiles dihalogen and copper(II) halides are discussed. n(-Diiodine coordination vs. diiodine oxidative addition has been observed in reactions of bis-orthochelated platinum(II) compounds [Pt(R) (C6H3{CH2NMe2) 2-2,6)] with diiodine. When R = I the reaction stops at the stage of the stable n’-I2 complex whereas when R = 4-tolyl the PtIV oxidative addition product is obtained. On the bases of these novel findings a mechanism for the reactions of dihalogens with d8 metal complexes is proposed. Reactions of diorganoplatinum compounds with CuIIX2 provide the platinum(IV) oxidative addition products rather than products originating from PtII-C bond cleavage reactions. A new mechanism is proposed for these reactions involving the formation of various types (depending on the type of chelated ligand) of encounter complexes of the organoplatinum(II) substrates with either the CuII or the X (terminal or bridging) centres of a polynuclear (CuIIX2)n species. © 1990 IUPAC