The Mixed Chromium(III) Complexes containing Acetylacetone and the Halogenations Thereof

The following three mixed chromium(III) complexes containing acetylacetone, which had a charge of from −1 to +1, were prepared: NH4[Cr(acac)(ata)]·H2O, [Cr(acac)(edda)]·2H2O and [Cr(acac)(edma)(H2O)]Cl·H2O. The halogenations at γ-position of the acetylacetonate ring were attempted in these three mixed complexes with NCS, NBS and ICl respectively in methanol and in acetic acid solutions, where NCS, NBS and ICl are abbreviated forms of N-chlorosuccinimide, N-bromosuccinimide and iodine monochloride, respectively. From an inspection of UV-spectra of the above halogenation reaction mixtures, all the three mixed complexes were confirmed to be halogenated at the γ-position of the acetylacetonate ring. Of these complexes, NH4[Cr(acac-Cl)(ata)]·12H2O and [Cr(acac-Br)(edda)] were isolated as crystals from the reaction mixtures. IR-spectra measurement was also used to certify the halogen-substitution at γ-position in the above two compounds.