Complexes of highly lewis acidic group 13 metals are in general unable to undergo redox transformations due to the lack of accessible redox states in the metal. Herein, we demonstrated the ability of iminopyridine complexes of aluminum to span five oxidations states, as well as display transition metal like reactivity and electronic structure. Complexes containing neutral, monoanionic, and dianionic iminopyridine ligands have been characterized structurally and electronically; yellow (IP)AlCl3, green (IP-)2Al(Cl), and purple [(IP2-)2Al]-. Variable temperature magnetic susceptibility and EPR spectroscopy measurements have shown that (IP-)2AlCl contains two ligand based radicals stabilized by antiferromagnetic coupling through the aluminum(III) center. In addition, redox transformations at the aluminum center have been achieved through both one and two electron oxidations of the [(IP2-)2Al]- anion. Cation dependant reactions with pyridine-N-oxide and [(IP2-)2Al]- have yielded two aluminum hydroxide complexes, (IP-)2Al(OH) and [Na(THF)(DME)][(IP-)(IP2-)Al(OH)], through acid base and C-H activation pathways respectively.

Mimicking transition metal reactivity with aluminum complexes of redox active ligands

243rd National Meeting (2012)

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