Electronic-structure of Bimetallic Flyover-bridge Derivatives - Uv-pes and Abinitio Study of Fe2(CO)6[(r-C2-r)2CO] and Ru2(CO)6[(r-c2-r)2CO] (r = C2H5)

T h e gas-phase UV-photoelectron (UV-PE) spectra of hexacarbonyl[p-( 1,2,5-7: I ,4,5-~) -3-0xo- 1,2,4,5-tetraethyl-l,4-pentadiene- 1,5-diyl]diiron(Fe-Fe) (1) and -diruthenium(Ru-Ru) (2) (“flyover-bridge” complexes) a r e reported. T h e assignment of experimental d a t a has been carried out by means of theoretical results obtained by the a b initio pseudopotential method. T h e main source of bonding between M2(CO)6 and the organic fragment has been found t o imply a n interaction between metal and the terminal carbon a toms of t h e organic moiety essentially u in nature