Figure 3.
Molecular orbital diagram of the Mo bis- and tris-dithiolene complexes. The tris-dithiolene complexes (far left and far right) adopt a trigonal prismatic structure with the z-axis defined along the C3 rotation axis. The Mo(IV) bis-dithiolene complex (middle left) is a square pyramid with the z-axis defined along the Mo-O(Si) bond and the x-axis bisecting the S-Mo-S chelate angle. The Mo(VI)=O bis-dithiolene (middle right) is distorted octahedral with the z-axis along the Mo=O bond and the x-axis bisecting the S-Mo-S chelate angle of the dithiolene cis to the oxo ligand. Note that some carbon and hydrogen atoms have been removed from the orbital pictures for clarity and that energy levels are shifted so that the relative LUMO energies reflect the differences seen in the S K-edge data.