Abstract The preparation and the electronic spectral properties of compounds M[Al(OR)4]2 (M = Co, Ni, Cu and R = CH3, C2H5, n-C3H7, n-C4H9) are described. The spectral data are used in conjunction with ligand field theory in deducing the structures of the compounds. The spectrum of green Ni[Al(OR)4]2 is interpreted as a Ni(OR)6 octahedron sharing faces with two Al(OR)4 tetrahedrons. It is proposed that Co 2+ and Cu 2+ are in a distorted octahedral coordination. The alkoxide ligands have been fitted into the spectrochemical and the nephelauxetic series. They are close to H2O in this series.
An introduction to transition-metal chemistry: Ligand field theory (Orgel, Leslie E.)