Pentadienyl, cyclohexadienyl, and arene uranium borohydride complexes

The compounds (η-2,4-dimethylpentadienyl)U(BH4)3 (2) and (η-6,6-dimethylcyclohexadienyl)2U(BH4)2 (5) were obtained from the reactions of U(BH4)4 (1) with the corresponding potassium dienyl anions; treatment of (η-2,4-Me2C5H5)3U with TIBH4 gave (η-2,4-Me2C5H5)2 U(BH4)2 (3) and the equimolecular mixture of (5) and (1) was transformed into (η-6,6-dimethylcyclohexadienyl)U(BH4)3 (4), whereas reduction of (1) in mesitylene afforded the arene complex (η-mesitylene)U(BH4)3 (6). (author)