REACTION OF LENYL)DICARBONYL(ETA(5)-CYCLOPENTADIENYL)RUTHENIUM WITH NONACARBONYLDIIRON - SYNTHESIS AND CHARACTERIZATION OF IRON-RUTHENIUM MIXED-METAL PRODUCTS

Reaction of Cp(CO)(2)RuCH=C=CH2 with Fe-2(CO)(9) in hexane at reflux a ffords four iron-ruthenium products: Cp(CO)(2)Ru(mu(3)- eta(1), eta(2) , eta(3)-C(O)CH=C=CH2)Fe-2(CO)(6) (3), )-CO)RuCp(mu(2)-CO)Fe(CO)(3)(mu (3)-eta(1)-CCH=CH2) (4), Cp(CO)(2)Ru(mu(4)-eta(1),eta(3),eta(3) eta(1) - H2CCHC(CH)CH2)(CO)(3)FeFe(CO)(2)(mu(2)-CO)Ru(CO)Cp (5) and (CO)CpFe( CO)(3)(mu(3)-eta(1),eta(1),eta(3)-CCHCH2) (6), which were isolated and characterized. Complex 3 reacts with PPh(3) to yield the monosubstitu tion derivative 1),eta(3),eta(3)-C(O)-CH=C=CH2)Fe-2(CO)(5)(PPh(3)) (10 ); both 3 and 10 were characterized spectroscopically and are thought to contain a Ru-bonded allenylcarbonyl ligand, which is attached to Fe -2(CO)(5)L (L = CO, PPh(3)) through the oxygen atom and the two C=C do uble bonds. The trinuclear 4 is structurally analogous to the previous ly prepared (C.E. Shuchart, A. Wojcicki, M. Calligaris, P. Faleschini and G. Nardin, Organometallics, 13 (1994) 1999), from Cp(CO)(2)RuCH2C= CPh and Fe-2(CO)(9), -CO)RuCp(mu(2)-CO)Fe(CO)(3)(mu(3)-eta(1)-CCH=CHPh ) (1) and contains a mu(3)-eta(1)-CCH=CH2 ligand capping an Fe2Ru meta l core. In solution, 4 and 1 undergo partial conversion to 6 and CO)Cp Fe(CO)(3)(mu(3)-eta(1),eta(1),eta(3)-CCHCHPh) (2), respectively, in wh ich the CCHCHR (R = H, Ph) ligand bridges the Fe2Ru triangle in a mu(3 )-eta(1),eta(1),eta(3) mode. Complexes 6 and 2 also equilibrate to mix tures of 6 and 4 and of 2 and 1, respectively, upon storage in solutio n. 1 reacts with 2 equiv. of PEt(3) in the presence of Me(3)NO to affo rd the disubstituted -CO)RuCp(mu(2)-CO)Fe(CO)(3)(mu(3)-eta(1)-CCH=CHPh ) (9), in which the bridging CCH=CHPh ligand retains its mu(3)-eta(1) bonding mode. In contrast, reactions of 1 and 4 with PPh(3) yield )-CO )Fe(CO)(3)(mu(3)-eta(1),eta(1),eta(3)-CCHCHPh) (8) and 2)-CO)Fe(CO)(3) (mu(3)-eta(1),eta(1),eta(3)-CCHCH2) (7), respectively, which contain m u(3),eta(1),eta(1),eta(3)-CCHCHR (R = H, Ph). The tetranuclear Fe2Ru2 complex 5 results from the coupling of two FeRu allenyl or related spe cies between a terminal and a central carbon atom of their C-3 fragmen ts. The structures of 4 and 8 (as 8 . 0.5CH(2)Cl(2)) were determined b y X-ray diffraction analysis. 4: monoclinic, P2(1)/n, a = 9.038(1) Ang strom, b = 15.062(6) Angstrom, c = 13.485(4) Angstrom, beta = 99.16(1) degrees, Z = 4, R = 2.8%, R(w) = 2.9%; 8 . 0.5CH(2)Cl(2): monoclinic, C2/c,39.851(9) Angstrom, b = 9.319(2) Angstrom, c = 21.156(5) Angstrom , beta = 112. 91(2)degrees, Z = 8, R = 4.02%, R(w) = 4.81%.