Nickel complexes crystal structure

A crystal-structure determination on [Ni(PhCH2CS2)2] showed evidence of a Ni-Ni bond (Ni—Ni distance, 256 pm) in a bridging, acetate-cage, binuclear complex (363). Each nickel atom is 5-coordinate and is in a tetragonally distorted, square-pyramid spectroscopic evidence for a Ni-Ni bond has been obtained (364). The polarized crystal spectra showed more bands than predicted for a mononuclear, diamagnetic, square-planar nickel(Il), and the spectra are indicative of substantial overlap of the d-orbitals between the two nickel atoms. The bis(dithiobenzation)nickeKII) complex was found to exhibit unusual spectrochemical behavior (365). 

An X-ray crystal-structure determination (370) revealed that mixed, nickel coordination exists in the trimeric complex, [Ni(S2CPh)2]3. The trimeric structure is similar to that found (371) in [Pd(PhCS2>]. The structure contains one molecule of type A linked centrosymmetrically through short Ni-S bridges to two molecules of type B, the three molecules being closely parallel (XXVII). Bonamico and co-workers (372)... 

One of the few crystal structures solved for a metal complex of a heterocyclic thiosemicarbazone is bis(l-formylisoquinoline thiosemicarbazone) nickel(II) monohydrate, [Ni(21-H)2] (Fig. 5) [208]. The nickel(II) center was found to be NNS coordinated by two approximately planar thiosemicarbazone ligands. 

Ni3(2,2,2-tet)3(/u-N3)3](PF6)3 and its perchlorate analogue have been suggested as trinuclear complexes with an irregular triangle structure.2117 While a crystal structure is lacking, EXAFS and XANES spectra support the occurrence of azido-bridged trinuclear nickel(II) compounds with Ni- -Ni separations of 5.16 A and 5.12 A, respectively. Two J parameters had to be... 

Reduction of both nickel porphyrins and thiaporphyrins to Ni1 species has been studied by EPR and 2H NMR spectroscopy.179, 2 58 The Ni1 complex of 5,10,15,20-tetraphenyl-21-thiaporphyrin has been isolated and characterized. Reaction of this complex with sulfur dioxide produced a paramagnetic five-coordinated Ni1 S02 adduct, while reaction with nitrogenous base ligands (amines, pyridines, imidazoles) yielded five- and six-coordinate complexes. In addition, the crystal structure of Ni1 diphenyldi-p-tolyl-21-thiaporphyrin has been determined. The coordination geometry about the nickel center is essentially square planar with extremely short Ni—N and Ni—S bonds (Ni—N = 2.015(2) A, 2.014(12) A, and 1.910(14) A and Ni—S = 2.143(6) A).2359... 

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... 

Ellis, J.W., Harrison, K.N., Hoye, P.A.T., Orpen, A.G., Pringle, P.G., and Smith, M.B., Water-soluble tris(hydroxymethyl)phosphine complexes with nickel, palladium, and platinum. Crystal structure of Pd P(CH2OH)3 4].cntdot.CH3, Inorg. Chem., 31, 3026, 1992. 

As in the previous chapter, most work has been carried out on oxides, and these figure prominently here. As the literature on oxides alone is not only vast but is also rapidly increasing, this chapter focuses upon a number of representative structure types to explain the broad principles upon which the defect chemistry depends. However, despite considerable research, the defect chemistry and physics of doped crystals is still open to considerable uncertainty, and even well-investigated simple oxides such as lithium-doped nickel oxide, Li Nij- O, appear to have more complex defect structures than thought some years ago. 

Recently, the crystal structure of a nickel(II) complex with a tridentate silyl ligand has been reported [20]. The structure in the solid state shows an //2-(Si-H) binding to nickel, with a Ni-H distance of 1.47 A NMR spectra of the complex in solution at -80 °C suggest the formation of a nickel(IV) hydride species through oxidative addition of the silyl-hydrogen to nickel [20]. 

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