Neutral Square Planar Cobalt(III) Complexes

Article abstract of DOI:10.1021/ja00210a018

The monoanionic square planar cobalt(III) complex, 4-HMPA-DMP)> (4) (H4HMPA-DMP = 2,4-bis(2-hydroxy-2-methylpropanamido)-2,4-dimethyl-3-oxopentane), has been prepared and characterized by 1H NMR, solid state and solution magnetic properties, X-ray crystallography, and IR spectroscopy.Compound 4, and related anionic square planar cobalt(III) complexes, can be alkylated at an amido-N oxygen atom to afford the first examples of neutral square planar cobalt(III) complexes.These species have been characterized by 1H NMR, solid-state magnetic properties, mass spectroscopy and elemental analysis, a solution molecular weight determination, and IR spectroscopy.All of the compounds exhibit well-resolved paramagnetically shifted 1H NMR spectra.Depending upon the donor properties, certain PAC ligands afford stable octahedral cobalt(III) complexes whereas others produce the coordinatively unsaturated square planar complexes.This is of potential significance in the search for new inorganic reagents for atom-transfer and inner-sphere oxidations.