Photochemical reactions of Fe(CO)<SUB>5</SUB> with monometal alkynyls and free alkynes: Synthesis and characterization of [(&#951;<SUP>5</SUP>-C<SUB>5</SUB>Me<SUB>5</SUB>)Fe<SUB>2</SUB>Mo(CO)<SUB>7</SUB>{&#956;<SUB>3</SUB>-&#951;<SUP>1</SUP>:&#951;<SUP>4</SUP>:&#951;<SUP>2</SUP>- C(H)C(Ph)C(Ph)C}] and diferrocenylquinones

Photolysis of a benzene solution containing Fe(CO)5 and [(&#951;5-C5R5)Mo(CO)3(C&#8801;CPh)] yielded mixed-metal clusters [(&#951;5-C5R5)Fe2Mo(CO)8(&#956;3-&#951;1:&#951;2:&#951;2-CCPh)] (R = H, 1; Me, 2) and [(&#951;5-C5H5)Fe3Mo(CO)11(&#956;4-&#951;1:&#951;1:&#951;2:&#951;1-CCPh)] (3). When a mixture of [(&#951;5-C5Me5)Mo(CO)3(C&#8801;CPh)], Fe(CO)5, and phenylacetylene was photolyzed, coupling of the acetylide and acetylene was observed and the mixed-metal cluster [(&#951;5-C5Me5)Fe2Mo(CO)7(&#956;3-&#951;1:&#951;4:&#951;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 1H and 13C NMR spectroscopy. Structures of 2-7 were established crystallographically