MICROWAVE ASSISTED SYNTHESIS AND CHARACTERIZATION OF CR(III) PYRAZOLATE- FORMATE MIXED-LIGAND COMPLEXES

Jessica M. López¹ and Raphael G. Raptis¹

1Florida International University, Miami, FL, 33199

Chromium acetate and formate complexes have been studied extensively, in contrast to their structurally analogous pyrazolates. The low lability of pyrazolates provides advantages over the carboxylate analogs. Herein, we present the synthesis of new Cr(III) complexes with different pyrazolate derivatives. Complexes were prepared by the reaction of Cr(NO₃)₃·9H₂O and the appropriate pyrazole ligand (4-R-pzH, R= H, Cl, Me) in dimethylformamide (DMF) using a microwave reactor. Hydrolysis of solvent and deprotonation of pyrazole yield the formation of trinuclear formate-pyrazolate mixed-ligand complexes with formula [Cr^III₃(μ₃-O)(μ-4-R-pz)₃(μ-COOH)₃(DMF)₃]⁺. All products were analyzed by single crystal X-Ray Diffraction, ¹H- NMR and infrared (IR) spectroscopy.