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

Abstract

The synthesis and spectroscopic characterisation of the new diborane(4) compounds B 2(1,2-O 2C 6Cl 4) 2 and B 2(1,2-O 2C 6Br 4) 2 are reported together with the diborane(4) bis-amine adduct [B 2(calix)(NHMe 2) 2] (calix=Bu tcalix[4]arene). B–B bond oxidative addition reactions between the platinum(0) compound [Pt(PPh 3) 2( η-C 2H 4)] and the diborane(4) compounds B 2(1,2-S 2C 6H 4) 2, B 2(1,2-O 2C 6Cl 4) 2 and B 2(1,2-O 2C 6Br 4) 2 are also described which result in the platinum(II) bis-boryl complexes cis-[Pt(PPh 3) 2{B(1,2-S 2C 6H 4)} 2], cis-[Pt(PPh 3) 2{B(1,2-O 2C 6Cl 4)} 2] and cis-[Pt(PPh 3) 2{B(1,2-O 2C 6Br 4)} 2] respectively, the former two having been characterised by X-ray crystallography. In addition, the platinum complex [Pt(PPh 3) 2( η-C 2H 4)] reacts with XB(1,2-O 2C 6H 4) (X=Cl, Br) affording the mono-boryl complexes trans-[PtX(PPh 3) 2{B(1,2-O 2C 6H 4)}] 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.