Polynuclear alkyne complexes

Went, Michael J., Synthesis and Reactions of Polynuclear Cobalt-Alkyne Complexes. 41 69... 

The resulting alkyne complex is capable of catalytically hydrogenating diphenylacetylene at 50 °C and 1 bar of H2 with TOF close to 50 h-1. The hydrogenation rate is first order in cluster concentration, indicating the participation of polynuclear species in the cycle, and it is also first order in substrate and hydrogen concentrations, while it is inhibited by CO. Labeling studies involving D2... 

Synthesis and Reactions of Polynuclear Cobalt-Alkyne Complexes... 

In 1974, Dickson and Fraser reviewed the already substantial area of cobalt-alkyne complexes.1 Since then the number of examples and applications of this class of organometallic compounds, especially dinuclear complexes, has increased enormously. This review will present the chemistry of polynuclear cobalt-alkyne complexes, with emphasis on the more recent developments. Although there have been many exciting fundamental discoveries, this is a maturing area of research that is finding many important applications in organic synthesis,2 such as the use of [Co2(jU-alkyne)(CO)6] complexes in the synthesis of enediyne antitumor antibiotics.3-4... 

Continuing expansion of the chemistry of polynuclear cobalt-alkyne complexes is expected, especially in the areas of reactivity and synthetic applications, in the coming years. 

On the basis of these observations and the known structures of a few polynuclear copper complexes, we suppose that CuC=CR is a part of a soluble complex, e.g. structure 26 . The coordination number of the copper is probably 4 and the ligands (L) may be amine, alkyne, etc. In the coupling reaction, the slow step is the release or transfer of X from carbon. These speculations lead to something like the progression in equation (271). 

Went, M. J. Synthesis and reactions of polynuclear cobalt-alkyne complexes. Adv. Organomet. Chem. 1997,41, 69-125. 

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