Metal-Ligand Multiple Bonds in High-Spin Complexes
Contributors: Betley, Theodore A.; Holm, Richard H.; Ritter, Tobias
Published: 2012
Language: eng
Description: The chemistry of late first row transition metals supported by dipyrromethane and dipyrromethene ligands bearing sterically bulky substituents was explored. Transition metal complexes (Mn, Fe, Co, Ni, Zn) of the dipyrromethane ligand 1,9-dimesityl-5,5-dimethyldipyrromethane (dpma) were prepared. Structural and magnetic characterization (SQUID, EPR) of the bis-pyridine adducts (dpma)Mn(py)2, (dpma)Fe(py)2, and (dpma)Co(py)2 showed each tetrahedral divalent ion to be high-spin, while square planar (dpma)NiII(py)2 and tetrahedral (dpma)Zn(py)2 were shown to be diamagnetic. Electrochemical experiments revealed oxidative events at common potentials independent of metal identity or spin state, consistent with ligand-based oxidation.
Notes: Keywords: catalysis, C-H functionalization, cobalt imido, H-atom transfer, iron imido, ligand non-innocence.

Thesis Ph.D. Harvard University 2012