Regioselective B(3)-H bond activation based on an o-carboranyl dithiocarboxylate ligand and its derivatives

Herein, we describe the synthesis of tetraphenylphosphonium o-carboranyl dithiocarboxylate (Ligand 1) and methyldithiocarboxyl-o-carborane (Ligand 2). The complexes [Cp*M(o-C₂B₁₀H₁₁CS₂)Cl] (M = Ir (3); Rh (4)) and [Cp*M(o-C₂B₁₀H₁₁CS₂)₂] (M = Ir (5); Rh (6)) have been synthesized based on Ligand 1. The selective B-H bond activation of Ligand 2 has also been explored, leading to the synthesis of the B-H activated complex [Cp*Ir(o-C₂B₁₀H₁₀CS₂CH₃)Cl] (7) and four of its substituted derivatives (8, 9, 10 and 11). All of these compounds have been characterised through single-crystal X-ray diffraction, NMR, IR spectroscopy and elemental analysis.