Spectroscopic and Electronic Properties of Molybdacarborane Complexes with Non-innocently Acting Ligands.

The molybdacarboranes [3-{L-κ2 N,N}-3-(CO)2 -closo-3,1,2-MoC2 B9 H11 ] (L=2,2'-bipyridine (2,2'-bpy, 1 a) or 1,10-phenanthroline (1,10-phen, 1 b)) incorporating well-known potentially non-innocent ligands (CO, 2,2'-bpy, 1,10-phen) and the "non-spectator" nido-carborane ([η5 -C2 B9 H11 ]2- ) ligand were prepared and fully characterised. High-resolution mass spectrometry, single-crystal X-ray diffraction methods, spectroscopy (IR, (resonance) Raman, NMR), cyclic voltammetry and spectroelectrochemistry (electrochemical properties) were supported by theoretical investigations of the electronic structure (DFT, CAS-SCF, TD-DFT).