HETEROBIMETALLIC SESQUIFULVALENE AND HYDROSESQUIFULVALENYL MANGANESE(I) CHROMIUM(0) COMPLEXES

The synthesis of the heterobimetallic sesquifulvalene complex (OC)(3)M n(mu-eta(5):eta(7)-C5H4-C7H6)Cr(CO)(3)]BF4 (2) is reported. 1-yl)-eta( 5)-cyclopentadienyl]tricarbonylmanganese (3) reacts with (CH3CN)(3)Cr( CO)(3) to give a mixture of endo- and o-[(OC)(3)Mn(mu-eta(5):eta(6)-C5 H4-C7H7)Cr(CO)(3)] (4a,b). Hydride abstraction from this mixture resul ted in the formation of 2 in low yield. Alternatively, Stille coupling of 2-trimethylstannyl-1,3,5-cycloheptatriene (5) with (iodocyclopenta dienyl)tricarbonylmanganese (6) gave 2-yl)-eta(5)-cyclopentadienyl]tri carbonylmanganese (7). After treatment of 7 with (CH3CN)(3)Cr(CO)(3), a mixture of two heterobimetallic complexes [(OC)(3)Mn(mu-eta(5):eta(6 )-C5H4C5H7)Cr(CO)(3)] (8a,b) was isolated. In 8a, a bridging (1,3,5-cy cloheptatrien-2-yl)-cyclopentadienyl Ligand was found, while 8b contai ns a (1,3,5-cycloheptatrien-1-yl)-cyclopentadienyl ligand. The mixture 8a, b was converted quantitatively into 2 by reaction with triphenylc arbenium tetrafluoroborate. The X-ray crystal structures of 2, 4a,4b a nd 8a are reported.