Reactivity of Tetrahalo- and Difluorodiboranes(4) toward Lewis Basic Platinum(0): Bis(boryl), Borylborato, and Doubly Boryl-Bridged Platinum Complexes.

The reaction of the tetrahalodiboranes(4) BF, BCl, and BBr with a Lewis basic platinum(0) complex led to the isolation of the cis-bis(difluoroboryl) complex cis-[(CyP)Pt(BF)] (1) and the novel borylborato complexes trans-[(CyP)Pt{B(X)-BX}] (2, X = Cl; 3, X = Br), respectively. The trans influence of the borylborato group was found to be one of the strongest ever observed experimentally. Furthermore, the reactivity of little-explored diaryldifluorodiboranes(4) FB-BMes and the new derivative FB-BAn (An = 9-anthryl) toward a range of platinum(0) complexes was investigated. Reactions with relatively nonbulky platinum(0) complexes led to the formation of unsymmetrical cis-bis(boryl) complexes cis-[(RP)Pt(BF)(BMes)] (6, R = Me; 7, R = Et) as well as the first example of a fourfold-unsymmetrical bis(boryl) complex, [(MeP)(CyP)Pt(BF)(BMes)] (12). The use of a more bulky Pt complex provided access to the unprecedented dinuclear bis(boryl) complexes [{( iPrP)Pt}(μ-BF)(μ-BAr)] (8, Ar = Mes; 9, Ar = An), which feature two different μ-bridging boryl ligands.