The dihydridoruthenium(IV) compound [RuH2Cl2(P i Pr3)2] (2), which is obtained on treatment of [RuCl2(C8H12)] n with P i Pr3 in 2-butanol in the presence of H2, reacts with PhC⋮CH in CH2Cl2 at 25 °C to give a mixture of [RuCl2(CCHPh)(P i Pr3)2] (4) and [RuCl2(CHCH2Ph)(P i Pr3)2] (5). Both complexes 4 and 5 as well as the methylcarbene derivative [RuCl2(CHCH3)(P i Pr3)2] (6) have been isolated; moreover, compounds 2 and 5 have been characterized by X-ray crystal structure analyses.

The ethene derivatives [(eta(5)-C(5)R(5))RuX(C(2)H(4))(PPh(3))] with R=H and Me, which have been prepared from the eta(3)-allylic compounds [(eta(5)-C(5)R(5))Ru(eta(3)-2-MeC(3)H(4))(PPh(3))] (1, 2) and acids HX under an ethene atmosphere, are excellent starting materials for the synthesis of a series of new halfsandwich-type ruthenium(II) complexes. The olefinic ligand is replaced not only by CO and pyridine, but also by internal and terminal alkynes to give (for X=Cl) alkyne, vinylidene, and allene compounds of the general composition [(eta(5)-C(5)R(5))RuCl(L)(PPh(3))] with L=C(2)(CO(2)Me)(2), Me(3)SiC(2)CO(2)Et, C=CHCO(2)R, and C(3)H(4). The allenylidene complex [(eta(5)-C(5)H(5))RuCl(=C=C=CPh(2))(PPh(3))] is directly accessible from 1 (R=H) in two steps with the propargylic alcohol HC triple bond CC(OH)Ph(2) as the precursor. The reactions of the ethene derivatives [(eta(5)-C(5)H(5))RuX(C(2)H(4))(PPh(3))] (X=Cl, CF(3)CO(2)) with diazo compounds RR'CN(2) yield the corresponding carbene complexes [(eta(5)-C(5)R(5))RuX(=CRR')(PPh(3))], while with ethyl diazoacetate (for X=Cl) the diethyl maleate compound [(eta(5)-C(5)H(5))RuCl[eta(2)-Z-C(2)H(2)(CO(2)Et)(2)](PPh(3))] is obtained. Halfsandwich-type ruthenium(II) complexes [(eta(5)-C(5)R(5))RuCl(=CHR')(PPh(3))] with secondary carbenes as ligands, as well as cationic species [(eta(5)-C(5)H(5))Ru(=CPh(2))(L)(PPh(3))]X with L=CO and CNtBu and X=AlCl(4) and PF(6), have also been prepared. The neutral compounds [(eta(5)-C(5)H(5))RuCl(=CRR')(PPh(3))] react with phenyllithium, methyllithium, and the vinyl Grignard reagent CH(2)=CHMgBr by displacement of the chloride and subsequent C-C coupling to generate halfsandwich-type ruthenium(II) complexes with eta(3)-benzyl, eta(3)-allyl, and substituted olefins as ligands. Protolytic cleavage of the metal-allylic bond in [(eta(5)-C(5)H(5))Ru(eta(3)-CH(2)CHCR(2))(PPh(3))] with acetic acid affords the corresponding olefins R(2)C=CHCH(3). The by-product of this process is the acetato derivative [(eta(5)-C(5)H(5))Ru(kappa(2)-O(2)CCH(3))(PPh(3))], which can be reconverted to the carbene complexes [(eta(5)-C(5)H(5))RuCl(=CR(2))(PPh(3))] in a one-pot reaction with R(2)CN(2) and Et(3)NHCl.

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The in situ generated species [IrCl(C8H14)(PiPr3)2] as well as the dihydrido complex [IrH2Cl(PiPr3)2] (15) were found to be quite reactive toward alkynes and diynes with either H or SiMe3 as substituents at the C⋮C and C⋮CC⋮C units. While the thermal or photochemical reaction of [IrCl(C8H14)(PiPr3)2] with Me3SiC⋮CR (R = Ph, Me, nBu, SiMe3, CH2OH, CMe2OSiMe3, CO2Et) led to trans-[IrCl{CC(SiMe3)R}(PiPr3)2] (3−9) for R = CO2Et via the isolated π-alkyne metal intermediate trans-[IrCl(η2-Me3SiC⋮CR)(PiPr3)2] (2), photolysis of 15 in the presence of Me3SiC⋮CC⋮CSiMe3 gave trans-[IrCl{CC(SiMe3)C⋮CSiMe3}(PiPr3)2] (19). Compound 19 was also obtained by thermal or photochemical rearrangement of trans-[IrCl(η2-Me3SiC⋮CC⋮CSiMe3)(PiPr3)2] (18). The dihydrido complex 15 reacted with HC⋮CC⋮CH at −60 °C to yield [{IrHCl(PiPr3)2}2(μ-C⋮CC⋮C)] (16) and with HC⋮CC⋮CSiMe3 to give [IrHCl(C⋮CC⋮CSiMe3)(PiPr3)2] (20), from which the vinylidene isomer trans-[IrCl(CCHC⋮CSiMe3)(PiPr3)2] (22) was generated on heating. The reaction of 15 with propargylic alcohols HC⋮CCR(R‘)OH led to different types of products, depending on the substituents R and R‘. Whereas for R = R‘ = iPr the five-coordinate alkynyl hydrido complex [IrHCl{C⋮CC(iPr)CMe2}(PiPr3)2] (23) was formed, the six-coordinate carbonyl hydrido vinyl derivative [IrHCl{(E)-CHCHPh}(CO)(PiPr3)2] (25) was isolated for R = H and R‘ = Ph. Treatment of 15 with HC⋮CCPh2OH afforded, via [IrHCl(C⋮CCPh2OH)(PiPr3)2] (27) or the isomer trans-[IrCl(CCHCPh2OH)(PiPr3)2] (28), the allenylideneiridium(I) compound trans-[IrCl(CCCPh2)(PiPr3)2] (29) in excellent yield. Hydrogenation of 29 gave the allene complex trans-[IrCl(η2-CH2CCPh2)(PiPr3)2] (30), the structure of which was determined by X-ray crystallography. The substituted vinylideneiridium compound trans-[IrCl{CC(SiMe3)C⋮CCPh2OH}(PiPr3)2] (33) was obtained from [IrCl(C8H14)(PiPr3)2] and Me3SiC⋮CC⋮CCPh2OH via the isomeric π-alkyne complex 32 as isolated intermediate.

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