CHEMISTRY OF POLYNUCLEAR ALLENYL COMPLEXES - THE MU-ETA-1-ETA-2-ALLENYL DIRUTHENIUM SYSTEM RU2(CO)6(MU-PPH2)(MU-ETA-1-ETA-2-C(PH)=C=CH2))DIMETALLOCYCLES VIA C-C, C-N AND C-S BOND-FORMING REACTIONS AND THE X-RAY STRUCTURE OF RU2(CO)6(MU-PPH2)[MU-ETA-1-ETA-1-PHC=C(C(ETS)N(H)TBU)CH2]

The mu-eta1:eta2-allenyl complex Ru2(CO)6(mu-eta1:eta2-C(Ph)=C=CH2)(mu-PPh2) (1), which has a structure with C(alpha)(Ph) coordinated to one ruthenium atom and the C(beta)=C(gamma) double bond attached to the second metal atom, undergoes regiospecific attack at C(beta) by (t)BuN=C to afford quantitative yields of an adduct Ru2(CO)6[mu-eta1:eta1-PhC=C(CN(t)Bu)CH2](mu-PPh2) (3), which has been characterized by microanalysis, IR and NMR spectroscopy. Complex 3 is converted into Ru2(CO)6(mu-PPh2)[mu-eta1:eta1-PhC=C(C-(EtNH)N(H)tBu}CH2] and Ru2(CO)6(mu-PPh2)[mu-eta1:eta1-PhC=C{C(EtS)N(H)tBu}CH2](5) by the addition of EtNH2 or EtSH respectively across the C=N bond of the 'carbon coordinated' isonitrile. The X-ray structure of 5 has been determined. Crystal data: C34H32NO6PRu2S.0.5CH2Cl2, monoclinic, space group P2(1)/n, a = 11.486(5), b = 14.956(5), c = 21.465(8) angstrom, beta = 101.82(2)degrees, Z = 4, R = 0.032, R(w) = 0.041. The nature of the amidinium and thioamidinium centres in 4 and 5 and the formation of the C-C, C-N and C-S bonds in 1 to form 3, 4 and 5 are discussed.