Supramolecular complexes, nickel

The authors assessed the catalytic activities of these supramolecular nickel complexes for the hydrocyanation of substituted styrenes with... 

Matienko, L.I. Binyukov, V.I. Mosolova, L.A. Mil, E.M. Zaikov, G.E. Supramolecular Nanostructures on the Basis of Catalytic Active Heteroligand Nickel Complexes and their Possible Roles in Chemical and Biological Systems. J. Biol. Res. 2012,1, 37-44. 

The great structural diversity of coordination patterns and supramolecular self-assembly has been analyzed in detail for nickel(II), zinc(II), mercury(II), and tellurium (II),246fe(xanthato) complexes. 

The structural chemistry of some metal dithiocarbamates, i.e. systematics, coordination modes, crystal packing, and supramolecular self-assembly patterns of nickel, zinc, cadmium, mercury,363 organotin,364 and tellurium,365 366 complexes has been thoroughly analyzed and discussed in detail. Supramolecular self-assembly frequently occurs in non-transition heavier soft metal dithiocarbamates. Thus, lead(II),367 bismuth(III)368 zinc,369 cadmium,370 and (organo)mercury371 dithiocarbamates are associated through M- S secondary bonds, to form either dimeric supermolecules or chain-like supramolecular arrays. The arsenic(III)372 and antimony(III)373 dithiocarbamates are... 

In contrast, Ni[pz(iV-Me2)8] C60 (lOOd) has a totally different supramolecular structure featuring a noncentrosymmetric 1 1 complex with a strongly warped pz unit. The plane of diametrically opposite pyrrole rings is being rotated by -30° with respect to each other about their N—N vectors with the nickel and the four coordinated nitrogen atoms are coplanar to within 0.006 A. Each C60 unit lies within a cleft formed by two steeply inclined (by -12°) Ni-pz molecules (Fig. 33), the shortest Ni—C (C60) distances are 3.29 and 3.64 A. 

Ethylenediaminetetraacetic acid, analogs, complexes of, 3 277 chelation by, 3 276-277 cobalt complex of, 3 281 complexes, 3 277-278 formation constant of, 3 273-274 -nickel, 3 17-18 stability of, 3 266-267 reaction with metal ions, 3 62 Ethylene dibromide, irradiation of, 5 196 4,5-Ethylenedithio-1,3-dithiole-2-thione based supramolecular complexes, 46 200-204 Ethylene glycol, 32 4... 

Chiper M, Meier MAR, Kranenburg JM, Schubert US. New insights into nickel(II), iron(II), and cobalt(II) bis-complex-based metaUo-supramolecular polymers. Macromol Chem Phys 2007 208 679-689. 

Similarly, when a mixture of the two tris-bipyridine ligands 129 and 148 is allowed to react simultaneously with copper(l) and nickel(il) ions, only the double helicate 132 and the triple helicate 149 are formed (Figure 49). Thus, parallel operation of two programmed molecular systems leads to the clean self-assembly of two well-defined helical complexes from a mixture of their four components in a process involving the assembly of altogether 11 particles of four different types into two supramolecular species. 

Supramolecular catalysis may also involve the combination of a host cavity and a metal active site as in the bis(diphenylphosphino)calix[4]arene nickel(II) complex 12.40 which acts as an efficient catalyst for ethylene and propylene polymerisation, and in tandem with zirconocene dichloride, for the formation of linear low-density polyethylene. In the latter case the complex gives very little branching - a significant advantage. The key to the effectiveness of the catalyst involves calixarene-induced changes in the bite angle at the Ni(II) centre, which is square planar in the active form of the catalyst.29... 

Of the transition metals, the nickel triad has been the most studied in terms of xanthate structures, especially nickel xanthates. Thus, binary xanthate structures are known for all elements with no less than 15 binary nickel xanthate structures known and these aggregate in the solid state in six distinct supramolecular architectures. There is also a rich diversity of adducts as well as mixed-ligand complexes, in particular for nickel. 

FIGURE 22 Preparation of supramolecular catalysts for hydrocyanation reactions (82) (A) assembly of heterodimeric chelating ligands (B) structure of the optimal nickel-diphosphine complex for hydrocyanation (other ligands of the metal center are omitted for clarity) and (C) hydrocyanation of functionalized styrenes. (For a color version of this figure, the reader is referred to the Web version of this chapter.)... 

Among the recent reports on metal xanthate chemistry the following are mentioned, dealing with the structural diversity of nickel(II),213 zinc(II),214 mercury(II), 15 and tellurium(II) bis (xanthate) complexes,216 based upon different coordination patterns and supramolecular self-assembly. 

The structural systematics, coordination modes, crystal packing and supramolecular self-assembly patterns of nickel,213 zinc,214 cadmium,393 mercury,394 organotin,395 and tellurium216,396 complexes of dithiocarbamato ligands have been analyzed. 

The first example of chiral tetranuclear supramolecular assembly 5.27 was reported by Saalfrank and coworkers in 1988. Thus the complex [(NH3)4n(Mg (22)5] (5.27) was obtained by serendipity upon treatment of the doubly bidentate ligand 22, which is formed in situ from malonic ester and oxalyl chloride, with MeMgl in aqueous ammonium chloride solution (Scheme 5.13). Later an improved one-pot reaction was used to prepare such tetrahedral complexes of magnesium, manganese, cobalt and nickel by treating the bis(chelate) ligand 22, obtained in situ, with MeLi/MCl2 followed... 

Fig. 2.7 Schematic representation of the preparation of gyroid metallic nanofoam, a Chemical structure of the supramolecular complex PS-h-P4VP(PDP). b Bicontinuous gyroid morphology of PS-h-P4VP(PDP). c Nanoporous template after PDP was removed, d By electroless deposition, the pores between PS struts are filled with nickel, e Gyroid nickel nanofoam after the polymer template was removed by pyrolysis. Adapted with the permission from Ref. [48]. Copyright 2011 American Chemical Society...

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