Copper complexes cyclopentadienyl

The types of compounds formed by gold(I) and gold(III) often differ from those of other metals due to the constraints imposed by coordination number and electron count at the metal. Thus, for example, whereas 7r-bonded cyclopentadienyl complexes of palladium and platinum are numerous (336), and a copper(I) species of this type is known (337), cyclopentadienyl complexes of univalent (94, 96, 97) and trivalent (228) gold have invariably been found to be fluxional behavior, similar to that in dicyclopentadienylmercury, was involved (228). 

The electrochemical technique has been relatively rarely applied to obtain the metal 7i-complexes [202,506,507], Thus, the electrosyntheses of complexes of copper with cyclo-octadiene and nickel with cyclo-octatetraene were reported [202,506,507]. The electrochemical reactions (3.242) are of especial interest, since they allow us to produce fe-cyclopentadienyl complexes [563-565] ... 

Another copper(i) complex possessing tetrahedral coordination is shown in Fig. 7-66 [187]. The central copper(i) ion is coordinated both to one l,l -bis(diphenyl-phosphino)ferrocene molecule (dppf) and one l,l -bis(oxodiphenylphosphoranyl)-ferrocene molecule (odppf). All the cyclopentadienyl rings are planar and mutually staggered (A/C) or half-staggered (B/D). 

The first metal-olefin complex was reported in 1827 by Zeise, but, until a few years ago, only palladium(II), platinum(Il), copper(I), silver(I), and mercury(II) were known to form such complexes (67, 188) and the nature of the bonding was not satisfactorily explained until 1951. However, recent work has shown that complexes of unsaturated hydrocarbons with metals of the vanadium, chromium, manganese, iron, and cobalt subgroups can be prepared when the metals are stabilized in a low-valent state by ligands such as carbon monoxide and the cyclopentadienyl anion. The wide variety of hydrocarbons which form complexes includes olefins, conjugated and nonconjugated polyolefins, cyclic polyolefins, and acetylenes. 

Alkenylboron compounds cyclopropanations, 9, 181 haloetherification, 9, 182 hydrogenation and epoxidation, 9, 182 metal-catalyzed reactions, 9, 183 metallic reagent additions, 9, 182 via radical addition reactions, 9, 183 5-Alkenylboron compounds, cross-coupling reactions, 9, 208 Alkenyl complexes with cobalt, 7, 51 with copper, 2, 160, 2, 174 with Cp Re(CO) (alkene)3 , 5, 915-916 with dicarbonyl(cyclopentadienyl)hydridoirons, 6, 175 with gold, 2, 255... 

Two other exchange reactions have been reported cyclopentadienyl-thallium and pentafluorophenylsilver react with a copper(I) halide to give cyclopentadienylcopper complexes (86) and pentafluorophenylcopper (203), respectively. 

In a recent study of the IR and NMR spectra of the cyclopentadienyl-copper and indenylcopper complexes with fcrf-butyl isocyanide, Saegusa and co-workers favored a rr-bonded structure for the former, but were uncertain of the latter 246). As the indenylcopper complex was deutera-ted at only positions 1 and 3 a preference was expressed for a o-bonded structure with 1,3-copper shifts. The structure of indenylcopper will doubtless be the subject of further research. 

In this group, too, the first observations were made by Thiele 192), who found that cuprous and silver ions are precipitated from aqueous ammoniacal solution by cyclopentadiene, but gave no analytical data. Thallium was later found to be precipitated similarly. Copper (I), however, also yields a white crystalline cyclopentadienyl-triethylphosphine complex, C5H5CuP(C2H5)3, which is stable to water 215) this was, in fact, analogous to an earlier method described by van Peski and Melsen. Attempts to make a complex by the Grignard reagent method or by the action of cyclopentadienyl sodium on cuprous halides were unsuccessful. 

Examples in organocopper chemistry are the synthesis of h -cyclopentadienyl-copper complexes with phosphite, phosphine or isocyanide ligands via the reaction of h -CjHjTl with Cu(I) halide-ligand complexes in pentane or THE at 25°C . 

The poly(pyrazolyl)borate ligands were developed by Trofimenko10 and have been used by him and others as cyclopentadienyl-like ligands which are capable of forming complexes that are often more stable than the analogous T s-cyclo-pentadienyl complexes. We have used this property to prepare a series of isolable, relatively stable copper(I) carbonyl complexes. The detailed syntheses of three complexes of this type, Cu(CO)[(pz)3BH], Cu(CO)[(Me2pz)3BH] (Me2pz = 3,5-dimethyl-l-pyrazolyl), and Cu(CO)[(pz)4B], are described below. 

Copper N-heterocyclic carbene complexes in catalysis 13CST912. Cyclopentadienyl-, indenyl- and fluorenyl-fimctionalized N-hetero-cyclic carbene metal complexes Synthesis and catalytic applications 12EJI1309. 

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