The NMR-Spectroscopic and X-ray Crystal-Structural Characterization of Two Cp*Ir Halfsandwich Complexes Containing the 1,2-Dicarba-closo-dodecaborane-1,2-diselenolato Ligand

The reaction of [Cp*IrCl2]2 with dilithium 1,2-ortho-carborane-1,2-diselenolate 3 leads to the green 16-electron diselenolene complex [Cp*Ir{Se2C2(B10H10)}] (4) which takes up two-electron ligands such as trimethylphosphane to give the 18-electron diselenolate derivative [Cp*Ir(PMe3){Se2C2(B10H10)}] (5). The molecular structures of 4 and 5 were determined by X-ray crystal structure analysis. The 77Se-nuclear shielding in 4 is lower by almost 500 ppm relative to that in 5.