Oxidative addition of boron-boron, boron-chlorine and boron-bromine bonds to platinum(0)

The synthesis and spectroscopic characterisation of the new diborane(4) compounds B-2(1,2-O2C6Cl4)(2) and B-2(1,2-O2C6Br4)(2) are reported together with the diborane(4) bis-amine adduct [B-2(calix)(NHMe2)(2)] (calix = Bu(t)calix[4]arene). B-B bond oxidative addition reactions between the platinum(0) compound [Pt(PPh3)(2)(eta-C2H4)] and the diborane(4) compounds B-2(1,2-S2C6H4)(2), B-2(1,2-O2C6Cl4)(2) and B-2(1,2-O2C6Br4), are also described which result in the platinum(II) bis-boryl complexes cis-[Pt(PPh3)(2){B(1,2-S2C6H4)}(2)], cis-[Pt(PPh3)(2){B(1,2-O2C6Cl4)}(2)] and cis-[Pt(PPh3)(2){B(1,2-O2C6Br4)}(2)] respectively, the former two having been characterised by X-ray crystallography. In addition, the platinum complex [Pt(PPh3)(2)(eta-C2H4)] reacts with XB(1,2-O2C6H4) (X = Cl, Br) affording the mono-boryl complexes trans-[PtX(PPh3)(2){B(1,2-O2C6H4)}] as a result of oxidative addition of the B-X bonds to the Pt(0) centre; the chloro derivative has been characterised by X-ray crystallography. (C) 1998 Elsevier Science S.A.