Photochemical reactions of Fe(CO)5 with monometal alkynyls and free alkynes:: Synthesis and characterization of [(η5-C5Me5)Fe2Mo(CO)7{μ3-η1:η4:η2-C(H)C(Ph)C(Ph)C}] and diferrocenylquinones

Photolysis of a benzene solution containing Fe(CO)(5) and [(eta(5)-C5R5)Mo(CO)(3)(Cequivalent toCPh)] yielded mixed-metal clusters [(eta(5)-C5R5)Fe2Mo(CO)(8)(mu(3)-eta(1):eta(2)-CCPh)] (R = H, 1; Me, 2) and [(eta(5)-C5H5)Fe3Mo(CO)(11)(mu(4)-eta(1):eta(1):eta(2):eta(1)-CCPh)] (3). When a mixture of [(eta(5)-C5Me5)Mo(CO)(3)(Cequivalent toCPh)], Fe(CO)(5), and phenylacetylene was photolyzed, coupling of the acetylide and acetylene was observed and the mixed-metal cluster [(eta(5)-C5Me5)Fe2Mo(CO)(7)(mu(3)-eta(1):eta(4):eta(2)-C(H)C(Ph)C(Ph)C)] (4) was obtained. Interestingly, use of a bulky substituent on the free acetylene in the reaction mixture did not produce analogues of 4. Reaction of Fe(CO)(5) with ferrocenylacetylene produced three different compounds, tetracarbonyl(2-ferrocenylmaleoyl)iron (5), 2,5-diferrocenylquinone (6), and 2,6-diferrocenylquinone (7). All new compounds were characterized by IR and H-1 and C-13 NMR spectroscopy. Structures of 2-7 were established crystallographically.