Supramolecular assemblies nickel

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... 

Nickel and platinum complexes of alkynols and alkynediols are an interesting class of organometallic complex self-associated by O-H- -O hydrogen-bond interactions. Their solid-state supramolecular assembly has been the subject of thorough studies [127]. 

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... 

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. 

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. 

Supramolecular systems assembled by peripheral and axial coordination were also thoroughly described. For example, heteroarrays held by axial coordination, particularly of zinc, nickel, ruthenium, tin, silicon, etc. porphyrins and phthalo-cyanines to peripheral pyridyl and 4,4-bipyridyl groups were described. Another interesting class of compounds are porphyrin dimers prepared by coordinative assembly of cw- icso-(4-pyridyl)porphyrins with PdCla forming two [PtCl2(pyP)2] complexes, and more complex tesselated structures by substitution of the platinum complex chloro ligands by 2,3-diamine(azaporphyrins), as depicted in Fig. 12. 

An exciting development in dithiocarbamate chemistry is the synthesis by Beer and co-workers (325,1489) of a range of supramolecular complexes containing nickel(II), zinc(II), and copper(II) bis(dithiocarbamate) centers. These include the preparation of nano-sized resorcarene-based polymetallic assemblies, copper(II) dithiocarbamate macrocycles (62,326,1469,1470), crown-ether derivatives (1471), cryptands (492), and catenanes (544). Details of this work are given in this section and also within the copper and zinc sections (Section IV.H.l and IV.I.l). 

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