Characterization and structures of the 2,2,7-trimethyl-3,5-octanedionate chelates of cerium(IV) and terbium(III)

The complexes Ce(tod)4 and Tb2(tod)6 were synthesized using hydrated metal nitrates and the β-diketone ligand H(tod), (tod=2,2,7-trimethyl-3,5-octanedione) with base neutralization. The metal complexes have been characterized by X-ray crystallography, elemental analysis, infrared spectroscopy, mass spectrometry, differential scanning calorimetry, and thermogravimetric analysis. The structure of Ce(tod)4 represents a new polymorph for tetrakis cerium chelates and Tb2(tod)6 is the first reported dimeric β-diketonate structure for terbium. These materials are promising precursor sources of cerium and terbium for thin film deposition, and are highly soluble in supercritical carbon dioxide, making them surrogates for hazardous waste remediation using supercritical fluid extraction.