CYCLOHEXADIENE AND BENZENE-DERIVATIVES OF [RU5C(CO)15]

The reaction of [Ru5C(CO)15] 1 with cyclohexa-1,3-diene and three equi valents of Me3NO yielded the new compound [Ru5C(CO)11(eta4-C6H8)2] 2 a nd also [Ru5C(CO)12(mu3-eta2:eta2:eta2-C6H6)] 3 and [Ru5-C(CO)12(eta6- C6H6)] 4 in approximately equal yields. The molecular structure of 2 h as been established by single-crystal X-ray diffraction. The two cyclo hexadiene ligands are terminally bound on opposite basal ruthenium ato ms of the square-pyramidal metal framework. Compound 2 may be converte d to 3 by reaction with carbon monoxide. The isomeric pair CO)10(mu3-e ta2:eta2:eta2-C6H6)(mu-eta2:eta2-C6H8)] 5 and [Ru5C(CO)10(eta6-C6H6)(m u-eta2:eta2-C6H8)] 6 may be prepared from 3 and 4, respectively, upon reaction with cyclohexa-1,3-diene and two equivalents of Me3NO. Cluste rs 5 and 6 have also been studied by single-crystal X-ray diffraction. In both molecules the cyclohexadiene ligand bridges a basal edge of t he square pyramid, while the benzene fragment is in face-capping and t erminal bonding mode, respectively.