Synthesis and Characterization of Two Novel Complexes of Cr(III) with Benzilmonoxime

Abstract

AbstractThe reaction of benzilmonoxime (BMOH) with CrCl3.6H2O in methanol gives the mono nuclear Cr(III) complex, [Cr(BMO)33 (1). Reaction of complex 1 with a methanolic solution of KOH at room temperature leads to a di‐nuclear Cr(III)‐Cr(III) complex, [Cr(BMO)2(OH)]2 (2). The complexes were characterized on the basis of their elemental analysis, Mass, IR, 1H and 13C‐NMR and electronic spectra. The IR studies were useful in assigning the coordination mode of the benzilmonoxime ligand to the chromium(III) ion. In addition, the presence of a hydroxo bridge in the dimeric complex 2 is inferred from the IR spectral studies. The electronic spectra of the complexes revealed two bands due to d–d transitions, and one band assignable to an oxygen (pπ)→Cr(eg*) LMCT transition observed in both complexes. An additional charge transfer transition, assignable to μ‐OH(pπ)→Cr(eg*), was only observed for the dimeric complex 2.The splitting energy and Racah parameter were calculated to be 18484 cm‐1 and 560 cm‐1 for [Cr(BMO)3] (1), 17986 cm‐1 and 545 cm‐1 for [Cr(BMO)2(OH)]2 (2) respectively.