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) B2 F4 , B2 Cl4 , and B2 Br4 with a Lewis basic platinum(0) complex led to the isolation of the cis-bis(difluoroboryl) complex cis-[(Cy3 P)2 Pt(BF2 )2 ] (1) and the novel borylborato complexes trans-[(Cy3 P)2 Pt{B(X)-BX3 }] (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) F2 B-BMes2 and the new derivative F2 B-BAn2 (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-[(R3 P)2 Pt(BF2 )(BMes2 )] (6, R = Me; 7, R = Et) as well as the first example of a fourfold-unsymmetrical bis(boryl) complex, [(Me3 P)(Cy3 P)Pt(BF2 )(BMes2 )] (12). The use of a more bulky Pt complex provided access to the unprecedented dinuclear bis(boryl) complexes [{( iPr3 P)Pt}2 (μ-BF2 )(μ-BAr2 )] (8, Ar = Mes; 9, Ar = An), which feature two different μ2 -bridging boryl ligands.