Physical and Structural Characterization of Ce(IV) β-Diketonate Complexes: Evidence for Geometrical Isomers in the Solid-State

The Ce(IV) β-diketonate complexes CeL 4 [where L is txhd (2,2,6-trimethyl-3,5-heptanedionate) 1; tmod (2,2,7-trimethyl-3,5-octanedionate) 2; tmhd (2,2,6,6-tetramethyl-3,5-heptanedionate) 3] were prepared by the interaction of the sodium salt of the diketonate with cerium(III) nitrate hexahydrate in aqueous ethanol solution. Differential scanning calorimetry and thermogravimetric analysis showed that 1 has a significantly lower sublimation temperature, but higher decomposition temperature than 3. The solid-state structures of the three complexes were determined via single crystal x-ray diffraction methods. Complex 2, which does not sublime, had significantly closer intermolecular contacts than those found for 1 and 3.