Nickel complexes homogeneous catalysis

Trimethylphosphane complexes of nickel, cobalt and iron — model compounds for homogeneous catalysis. H. F. Klein, Angew. Chem., Int. Ed. Engl., 1980,19, 362-375 (108). 

Nickel(0) complexes with water-soluble phosphines have attracted interest in the context of homogeneous catalysis. A comprehensive study of the coordination chemistry of tris(sodium-m-sulfonatophenyl)phosphine (1039) has appeared.2504 The complexes [Ni(CO)2(1039)2] 6HzO have been made by reaction of (1039) with Ni(CO)4 under phase-transfer conditions, and the homo-leptic [Ni(1039)3]-9H2O has been made from Ni° precursors and (1039) under phase-transfer conditions, or from NiCl2, (1039), and BH4 in water. A related complex [Ni(CO)2(1040)2] with the bidentate ligand (1040) has also been studied.2505... 

The catalytic cyclo-oligomerization of 1,3-butadiene mediated by transition-metal complexes is one of the key reactions in homogeneous catalysis.1 Several transition metal complexes and Ziegler-Natta catalyst systems have been established that actively catalyze the stereoselective cyclooligomerization of 1,3-dienes.2 Nickel complexes, in particular, have been demonstrated to be the most versatile catalysts.3... 

Nickel is frequently used in industrial homogeneous catalysis. Many carbon-carbon bond-formation reactions can be carried out with high selectivity when catalyzed by organonickel complexes. Such reactions include linear and cyclic oligomerization and polymerization reactions of monoenes and dienes, and hydrocyanation reactions [1], Many of the complexes that are active catalysts for oligomerization and isomerization reactions are supposed also to be active as hydrogenation catalysts. 

In this context, homogeneous catalysis has been increasingly used since it can offer valuable advantages, notably in terms of selectivity and efficiency. Indeed, low-valent complexes of transition metals like nickel, palladium, or cobalt can react with many functionalities, thus allowing numerous C,C-bond forming reactions. 

Another example is butene dimerization catalyzed by nickel complexes in acidic chloroaluminates 14). This reaction has been performed on a continuous basis on the pilot scale by IFF (Difasol process). Relative to the industrial process involving homogeneous catalysis (Dimersol process), the overall yield in dimers is increased. Similarly, selective hydrogenation of diene can be performed in ionic liquids, because the solubility of dienes is higher than that of monoene, which is higher than that of paraffins. In the case of the Difasol process, a reduction of the volume of the reaction section by a factor of up to 40 can be achieved. This new Difasol technology enables lower dimer (e.g., octenes) production costs 14). 

The NiY zeolite was also shown to be active for the cyclotrimerization of propyne with 1,2,4-trimethylbenzene being the main product. The activities of the above-mentioned transition metal ions for acetylene trimerization are not so surprising since simple salts and complexes of these metals have been known for some time to catalyze this reaction (161, 162). However, the tetramer, cyclooctatetraene, is the principal product in homogeneous catalysis, particularly when simple salts such as nickel formate and acetate are used as catalysts (161). The predominance of the trimer product, benzene, for the zeolite Y catalysts might be indicative of a stereoselective effect on product distribution, possibly due to the spatial restrictions imposed on the reaction transition-state complex inside the zeolite cages. 

Asynunetric Synthesis by Homogeneous Catalysis Cyanide Complexes of the Transition Metals Electronic Stmcture of Organometalhc Compounds Hydride Complexes of the Transition Metals Mechanisms of Reaction of Organometalhc Complexes Nickel Organometalhc Chemistry P-donor Ligands. 

Metal complex chemistry, homogeneous catalysis and phosphane chemistry have always been strongly connected, since phosphanes constitute one of the most important families of ligands. The catalytic addition of P(III)-H or P(IV)-H to unsaturated compounds (alkene, alkyne) offers an access to new phosphines with a good control of the regio- and stereoselectivity [98]. Hydrophosphination of terminal nonfunctional alkynes has already been reported with lanthanides [99, 100], or palladium and nickel catalysts [101]. Ruthenium catalysts have made possible the hydrophosphination of functional alkynes, thereby opening the way to the direct synthesis of bidentate ligands (Scheme 8.35) [102]. 

Hemocyanin/Tyrosinase Models Heterogeneous Catalysis by Metals Hydride Complexes of the Transition Metals Hydrocyanation by Homogeneous Catalysis Hydrogen Inorganic Chemistry Mechanisms of Reaction of Organometallic Complexes Nickel Organometallic Chemistry Oligomerization Polymerization by... 

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