Ligand structures nickel complexes

The ability of cobalt(II), nickel(II), and copper(II) to exhibit a greater tendency than Zn(II) towards bidentate coordination is further illustrated by structural comparisons within a series of bridging carbonate complexes (188). For example, of the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu, Zn), only the zinc derivative does not exhibit bidentate coordination at both metal centers (151,153). Furthermore, the carbonate ligand in the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu) also exhibits varying degrees of asymmetry that closely parallel the series of nitrate complexes described earlier (Fig. 47 and Table IX). 

Oxidaton of heme goes through the biliverdin species. Octaethylbiliverdin can exist in coordinated form as the fully reduced trianion (OEB)3-, as the two-electron-oxidized monoanion (OEBox), or as the one-electron-oxidized radical (OEB-)2-. Nickel forms complexes with all three moieties, [Nin(OEB)]ra with n I 1, 0, and -1 (689).1787 The most highly oxidized species [Ni(OEBox)]I3 could be crystallized. The structure shows a helical coordination of the linear tetrapyrrole ligand around nickel with Ni—N distances of 1.867 A and 1.879 A. 

Quite a number of silylnickel and silylenenickel compounds have been reported, and only a few can be cited here2305-2309 Bis(silyl)nickel complexes have been implicated as important intermediates in Ni-catalyzed double silylation of various organic substrates. Using an o-bis(dimethylsilyl)carborane ligand, complex (930) could be isolated and structurally characterized 2310 Its unusual thermal stability is attributed to the advantageous steric and electronic properties of the carboranyl unit. (930) undergoes... 

The crystal structures of two nickel-complexes which contain cis.ds-cyclooctadiene as chelate ligands are known (89). For complex formation the 2v -symmetric boat-form is most favourable. The energetical compromise in the complexes is therefore such that the... 

Kockerling, M. and Henkel, G. (2000) Synthesis and structure of [Ni4(S2C7Hio)4], the first tetranuclear cyclic nickel complex with bifunctional thiolate ligands and of the mononuclear precursor compound Na2[Ni(S2C7Hio)2]- 4MeOH. (PrOH)-Pr-i, Inorg. Chem. Commun., 3, 117-9. 

Kruger, H.-J., Peng, G. and Holm, R. H. (1991) Low-potential nickel(III,II) complexes - new systems based on tetradentate amidate thiolate ligands and the influence of ligand structure on potentials in relation to the nickel site in [NiFe]-hydrogenases. Inorg. Chem., 30, 734-42. 

Structure of the EDTA ligand and its complex with the nickel(ll) ion. 

The number of theoretical investigations of transition metal complexes with carbodiphosphoranes and related divalent carbon(O) ligands is rather small. Quantum chemical calculations of the nickel complexes (CO) Ni-C(PPh3)2 with n = 2, 3 have been pubhshed together with experimental work which describes the S3mthesis and X-ray structure analyses of the compounds [107]. The first systematic... 

Macrocyclic N-donor ligands. Nickel complexes of macrocyclic ligands have been studied by cyclic voltammetry, and the irreversible or quasi-reversible couples Ni" L Ni L Ni L have been established. The structure of (124) has been reported and the co-ordination is essentially square-planar with a slight tetrahedral distortion. The reaction of [Ni(pn)3] with... 

It has previously been shown that the oxazines (169) can isomerize by ringopening to the Schiff bases (170). The reactions of the oxazines with Ni , Co", and Cu" have now been examined in the hope of yielding chelates of the Schiff bases. However, the products were not the expected ones in the case of nickel, two kinds of chelate were obtained. Those formed in the absence of air were (171), in which proton migration from the original ligand had occurred, and, in the presence of air, (172) was formed in which dehydration had taken place on the original oxazine. The Co" and Cu" chelates are structurally analogous to the nickel complexes. ... 

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