Nickel bimetallic complexes

There are two possible pathways to homologate methanol with carbon dioxide the CO2 insertion path and CO insertion path (Scheme 2). As for the former, Fukuoka et al. reported that the cobalt-ruthenium or nickel bimetallic complex catalyzed acetic acid formation from methyl iodide, carbon dioxide and hydrogen, in which carbon dioxide inserted into the carbon-metal bond to form acetate complex [7]. However, the contribution of this path is rather small because no acetic acid or its derivatives are detected in this reaction. Besides, the time course... 

K. Jonas, Dilithium-nickel-olefin Complexes. Novel Bimetallic Complexes From a Transition Metal and a Main Goup Metal, Angew. Chem. Int. Ed. Engl. 14, 752-753 (1975). 

The coordination chemistry of the hexaphyrin system has provided a number of surprises [190]. The addition of nickel chloride to the isomeric mixture of hexaphyrins 250 leads to a single product. The proposed structure of the resulting nickel complex is shown as compound 254 in Scheme 44. Other metals were also found to react with this and other isomeric mixtures of hexaphyrins to give rise to only one isomeric product. For instance, treatment of either 250 or 252 with zinc chloride gives the bimetallic complexes 255 or 256 as one isomer, respectively (Scheme 45). In contrast, the reaction of 253 under identical conditions gives rise to a similar complex 257, wherein, the positions of the ter substituents are different from those reen in the previous examples (Scheme 46). The reactions of hexaphyrins with zinc would appear to indicate that the two isomers normally... 

Miscellaneous Reactions. 2,4,6,8-Tetraethenyl-2,4,6,8-tetra-methylcyclotetrasiloxane acts as a chelating ligand for a bimetallic nickel(O) complex, similar to Karstedt s catalyst. The combination of and tetramethylcyclotetrasiloxane in the presence of Karstedt s catalyst cross-links the two tetramers to prepare a platinum-containing glass.Additionally, Bennetau and Boileau have functionalized with CgFnI under ultrasonic irradiation conditions to provide tetra(perfluorooctyl)-substituted D4 after reductive cleavage of the iodide with tributyltin hydride. ... 

Ni(0) catalyst. A radical 5-exo cyclization to the potentially zinc or nickel-complexed ketone provides an alkoxyl radical that combines with the co-produced Ni(I) species. A transmetalation to a zinc alkoxide regenerates the catalyst and forms the zinc cyclopentoxide, from which products 79 are liberated on hydrolysis. A bimetallic Cu(I)-Mn(II) system provided similar results (see Sect. 8.4). Analogous samarium diiodide-mediated reactions require in contrast stoichiometric amounts of the reducing agent and are less diastereoselective [26, 27],... 

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