Hypoelectronic titanaboranes: icosahedral and tetracapped tetrahedral clusters comprising bridging hydrides

Abstract

Unusual hypoelectronic closo-clusters, such as icosahedral [(Cp*Ti)₃(B₉H₇)(μ₃-H)(μ₃-Cl)₂] (1) and tetracapped tetrahedral [{(Cp*Ti)₃B}(μ₃-BH₃)₂(μ₃-Te)₂] (2), have been synthesized and structurally characterized. Clusters 1 and 2 represent the first examples of closo-titanaboranes having bridging hydrides, where the Ti⋯Ti interactions play a pivotal role in defining their shapes and electron counts. Furthermore, two face-fused clusters, [(Cp*Ti)₂(μ-Se)(μ-SePh)(μ-η³:η³-B₅H₉R)] (3a: R = H; 3b: R = Ph), have been isolated that deviate from Mingos fusion formalism.