Allenylidene complexes binuclear

The ability of the binuclear complex [Cp RuCl(p2-SR)2RuCl(Cp )] to generate cationic allenylidene complexes by activation of terminal prop-2-ynols in the presence of NH4BF4 as a chloride abstractor opens the way to a variety of catalytic transformations of propargylic alcohols involving nucleophilic addition at the Cy atom of the ruthenium allenylidene intermediate (Scheme 19). This leads to the formation of a functional ruthenium vinylidene species which tau-tomerizes into an -coordinated alkyne that is removed from the ruthenium centre in the presence of the substrate. 

Allenylidene complexes, synthesis /z-allenylidene complexes, 225-227 binuclear compounds, 225, 225... 

Very recently, the water-soluble binuclear ruthenium allenylidene complex [ RuCl(ju-Cl)(C=C=CPh2)(Ph2P(2-0S(0)2C6H4))2 2] Na4 was used to perform selective transetherification of substituted vinyl ethers into acetals and aldehydes according to the solvent (Scheme 23) [110]. 

The homobimetallic, ethylene-ruthenium complex 15, which contains three chloro bridges, was readily obtained from the reaction of [RuCl2(/ -cymene)]2 with 1 atm of ethylene [34]. In 2009, Demonceau and Delaude [34] showed that complex 15 could be a useful precursor to allow subsequent access to the diruthenium vinylidene complex 16, allenylidene complex 17, and indenylidene complex 18 (Scheme 14.8). Upon reaction with propargylic alcohol, complex 15 afforded vinylidene complex 16, which converted into the allenylidene complex 17 in the presence of molecular sieves [34]. As shown in the acid-promoted intramolecular rearrangement of mononuclear ruthenium allenylidene complexes [19, 20, 32], the addition of a stoichiometric amount of TsOH to complex 17 at -50 °C led to the indenylidene binuclear complex 18 [34]. Complex 18 has been well... 

Formal insertion of CO2 into Fe-C bonds is formed in the reaction of Fe3(CO)i2 with hex-l-en-3-yne. The reaction consists in the splitting of water into its three components, favored by the tic silica used for purification. The final product is, however, a binuclear complex.Related to this behavior is the reaction of Fe3(CO)i2 with l-phenyl-2-propyn-l-ol where the allenylidene complex Fe3(GO)9(/x-GO) C=C=C(H)Ph 4 is obtained first. It reacts with methanol to form a ferrole-like methoxycarbonyl (or acetate) derivative. It has been also observed that similar binuclear complexes can be obtained by reacting Fe3(CO)i2 with propargyl alcohol or propargyl chloride in KOH/CH3OH solutions followed by acidification with HCl GO and methanol activation occurs in this instance to form binuclear methoxycarbonyl derivatives and the open cluster Fe3(GO)io H2GGG(H)G(=0)G[GH2(0)GH3GGH2] 5. ... 

Reaction of Fe3(CO)12 with 3-pentyn-l-ol gives the hydrido cluster 4, formed by coupling of an allenylidene unit with a coordinated carbonyl ligand and methoxy group. In contrast, reaction with the isomeric alkyne 2-methyl-3-butyn-2-ol affords a binuclear iron complex.18 Treatment of Fe3(p3-S)2(CO)9 with Me3NO affords the vinylferrocene complex 5, whereas the similar reaction with Fe3(p3-Te)2(CO)9 gives no cluster products.19... 

The use of Me3NO to induce substitution of dppm (bis(diphenylphosphino)-methane) for CO molecules on dinuclear iron complexes led to insertion of CO into C-C bonds of alkyne-derived metallacycles. Similar behavior was observed when [PPNJCl salts were used to favor the formation of alkyne-substituted triruthenium dppm-containing clusters.I This behavior should be compared with the insertion of CO into allenylidene and phosphido-bridging ligands occurring when dppm coordinates to binuclear ruthenium complexes as shown in Fig. 3. This reaction is a nucleophilic attack of the coordinated allenylidene and phosphido groups on a coordinated CO (see Section 2.8.2.2). 

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