Lewis Acid Decorated Hexacyanodiborane(6) Dianion.

First examples of diborane(6) dianions decorated with weakly coordination B(C 6 F 5 ) 3 (BCF) groups and SiEt 3 + moieties have been synthesized demonstrating the synthetic potential of the [B 2 (CN) 6 ] 2- dianion. [B 2 {CNB(C 6 F 5 ) 3 } 6 ] 2- (1) was isolated as potassium and tetrabutylammonium salt. 1 is a rare example for a weakly coordinating dianion and it was used for the stabilization of the carbocation [Ph 3 C] + and the oxonium acid [H(OEt 2 ) 2 ] + . Reaction of [Ph 3 C] 2 1 with HSiEt 3 resulted in the silylated neutral diborane(6) [B 2 {CNB(C 6 F 5 ) 3 } 4 (CNSiEt 3 ) 2 ] (2) in which two BCF groups have been selectively replaced by SiEt 3 + substituents, underscoring the stability and chemical versatility of the [B 2 (CN) 6 ] 2- dianion. The chemical properties and physicochemical data of 1 and 2 provide insight into electronic, coordinating, and steric properties of theses novel diborane(6) compounds.