Carbyne complex ruthenium

Oxidation of a cationic ds ruthenium carbyne complex by iodine has also been observed (39) ... 

Hydrogenation of a ruthenium carbyne complex leads to quantitative formation of the ruthenium phenyl hydride compound, which can be thermally reconverted to the ben-zyne complex... 

Carbene and Carbyne Complexes of Ruthenium, Osmium, and Iridium... 

Carbyne complex chemistry of osmium and ruthenium is discussed in this section. These studies demonstrate clearly the parallels that exist between the metal-carbon bonds in carbene and carbyne complexes and again emphasize the importance of metal basicity in determining complex reactivity. 

The reluctance of the carbyne carbon to react with nucleophiles is revealed by the reaction with LiEt3BH (see Scheme 6). Here the most electrophilic site is not the carbyne carbon but the ipara position of the aryl ring in the carbyne substituent Both ruthenium and osmium five coordinate, cationic, carbyne complexes undergo this reaction. The structure of a representative example, the osmium compound derived from the p-tolyl carbyne complex, has been determined by X-ray crystallography [16]. The unusual vinylidene complex reacts with HCl to produce a substituted benzyl derivative. The reaction may proceed through the intermediate a-vinyl complex depicted in Scheme 6 although there is also the possibility that the vinylidene compound is in equilibrium with the carbene tautomer as shown below. 

Support from the N.Z. Universities Grants Committee and the University of Auckland Research Committee is gratefully acknowledged. The author thanks all his coworkers named in the references but particularly Drs. James Wright and Tony Wright who were principally responsible for developing the carbyne complex chemistry of ruthenium and osmium. 

Dixneufs group [19, 20] has reported the intramolecular rearrangement of a ruthenium-bound allenylidene ligand into an indenylidene ligand. The stoichiometric protonation of arene-ruthenium-allenylidene complexes lla-c with TfOH at -40 °C gave the alkenyl carbyne complex 12, which, upon raising the temperature to -20 °C, completely transformed into the related, isolable arene-ruthenium, indenylidene complexes 13a-c (Scheme 14.6). The protonation of the allenylidene carbon at C2 generates a very electrophilic carbyne carbon at... 

While carbyne complex 12a did not effect the ROMP of unstrained cyclooctene, the cationic indenylidene complex 13a was found to catalyze this reaction with a turnover frequency (TOP) of more than 17000min [20]. In s/ta-generated arene-ruthenium indenylidenes 13a-b were also shown to be excellent catalysts for a variety of RCM reactions employing functional dienes and enynes [20]. 

September 1985) have been published. The 300th volume of J. Organomet. Chem. is commemorated by a number of reviews by well-known organometallic chemists many of these reviews are of relevance to this chapter. Carbene and carbyne complexes of ruthenium, osmium, and iridium,and the role of electrophilic metal carbenes as reaction intermediates in catalytic reactions, have been reviewed. The reactivity of the ions Ru", Rh", and Pd with alkanes in the gas phase has been shown to be markedly different to that of their first row congeners. 

OsCl2(CO)(CTe)(PPh3)2]. The cationic osmium carbyne complex, [Os(CR)-(CO)a(PPh3)2]+ (R=p-tolyl), reacts with LijBtsBH] to form the unusual vinylidene complex (34). Iron, ruthenium, and osmium carbene complexes are also discussed in Section 2 (refs. 8, 34, and 38). 

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