Nickel, 9:6 complex with

Dithioacetyacetone (sacsac) forms square planar complexes with Ni11, the chelate rings being six membered. A comparative IR, NMR, and13C NMR study of nickel complexes with sacsac... 

Nickel complexes with the dmid ligand are also less recognized in research. A conductivity as high as 10-2 Scm-1 was reached with (Et4N)o.i7[Ni(dmid)2].1036 (Bu4N)x[Ni(dmid)2] complexes have been studied by XPS and for applications in electrical switching and memory devices.1 7,1038... 

A great number of nickel complexes with thiosemicarbazide (432) and thiosemicarbazone (433) ligands and their substituted derivates have been examined. Thiosemicarbazone chemistry is... 

The electrochemistry of cobalt-salen complexes in the presence of alkyl halides has been studied thoroughly.252,263-266 The reaction mechanism is similar to that for the nickel complexes, with the intermediate formation of an alkylcobalt(III) complex. Co -salen reacts with 1,8-diiodo-octane to afford an alkyl-bridged bis[Co" (salen)] complex.267 Electrosynthetic applications of the cobalt-salen catalyst are homo- and heterocoupling reactions with mixtures of alkylchlorides and bromides,268 conversion of benzal chloride to stilbene with the intermediate formation of l,2-dichloro-l,2-diphenylethane,269 reductive coupling of bromoalkanes with an activated alkenes,270 or carboxylation of benzylic and allylic chlorides by C02.271,272 Efficient electroreduc-tive dimerization of benzyl bromide to bibenzyl is catalyzed by the dicobalt complex (15).273 The proposed mechanism involves an intermediate bis[alkylcobalt(III)] complex. 

Cj) Treatment of zero-valent nickel complexes with Br0nsted acids. 

C2) Treatment of zero-valent nickel complexes with Lewis acids, whereby the Lewis acid can also be an organometallic species. 

Some of these coupling reactions can be made catalytic if hydrogen is eliminated and combines with the anion, thus leaving the nickel complex in the zero-valent state. Allylation of alkynes or of strained olefins with allylic acetates and nickel complexes with phosphites has been achieved (example 38, Table III). 

Oxidation of carbon ligands with concomitant insertion has been observed in the reaction of methallyl nickel complexes with norbornene or strained olefins in general and oxygen (example 3, Table IX). 

Replacement reactions of aromatic halides or other halides with SCN, NCO, or N02 can be easily carried out by oxidation of nickel complexes with copper salts (examples 8-11, Table XI). 

Biaryl synthesis from aryl halides is a more interesting reaction due to the value of these molecules and their difficult access by chemical methods. The first electrosyntheses were simultaneously done in 1979-80 by three groups [21-23] who used NiCljPPha (1-20%) as catalyst precursor in the presence of excess PPhs. Later, several groups investigated the use of bidentate phosphines like dppe associated with nickel in the synthesis of various biaryls, and notably 2,2 -bipyridine and of 2,2 -biquinoline from respectively 2-chloropyridine and 2-chloroquinoline [24], More recently new nickel complexes with l,2-bis(di-2-alkyl-phosphino)benzene have been studied from both fundamental and synthetic points of view [25]. They have been applied to the coupling of aryl halides. 

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. 

For other examples of the use of volume profiles, see Refs. 171 (base hydrolysis of CofNHjljX" ), 172 (nickel complexing with glycolate and lactate) and general reviews. 

Fujiwara E, Kobayashi A, Kobayashi H (2003) Structures and physical properties of nickel complexes with TTF-type ligands. Synth Met 135-136 535-536... 

Fluoral has been condensed with an equivalent of chiral glycinate anion. The chirality stems from a chiral nickel complex with a chiral Schiff base derived from proline as hgand (Figure 5.17). (25, 35)-Difluorothreonine has thus been obtained with an excellent selectivity (de > 95%). This method also allows preparation of numerous fluoroalkyl and fluoroaryl analogues of threonine. Enantiopure difluorothreonine could also be prepared from ascorbic acid. ... 

We can now make sensible guesses as to the order of rate constant for water replacement from coordination complexes of the metals tabulated. (With the formation of fused rings these relationships may no longer apply. Consider, for example, the slow reactions of metal ions with porphyrine derivatives (20) or with tetrasulfonated phthalocyanine, where the rate determining step in the incorporation of metal ion is the dissociation of the pyrrole N-H bond (164).) The reason for many earlier (mostly qualitative) observations on the behavior of complex ions can now be understood. The relative reaction rates of cations with the anion of thenoyltrifluoroacetone (113) and metal-aqua water exchange data from NMR studies (69) are much as expected. The rapid exchange of CN " with Hg(CN)4 2 or Zn(CN)4-2 or the very slow Hg(CN)+, Hg+2 isotopic exchange can be understood, when the dissociative rate constants are estimated. Reactions of the type M+a + L b = ML+(a "b) can be justifiably assumed rapid in the proposed mechanisms for the redox reactions of iron(III) with iodide (47) or thiosulfate (93) ions or when copper(II) reacts with cyanide ions (9). Finally relations between kinetic and thermodynamic parameters are shown by a variety of complex ions since the dissociation rate constant dominates the thermodynamic stability constant of the complex (127). A recently observed linear relation between the rate constant for dissociation of nickel complexes with a variety of pyridine bases and the acidity constant of the base arises from the constancy of the formation rate constant for these complexes (87). 

The observed spectra of some duroquinone-nickel complexes with olefins have been correlated by means of semiquantitative molecular-orbital theory by Schrauzer and Thy ret (48). In the case of n complexes of polynuclear hydrocarbons, such as naphthalene and anthracene, although their spectra are recorded, no conclusions have been drawn with regard to structure nor has any theoretical work been reported. Similar remarks apply to complexes of nonalternant hydrocarbons such as azulene. Although innumerable complexes of olefins with various transition metals are known and admirably reviewed (84), no theoretical discussion of even a qualitative nature has been provided of their electronic spectra. A recent qualitative account of the electronic spectra of a series of cyclopentadienone, quinone, and thiophene dioxide complexes has been given by Schrauzer and Kratel (85). 

The complex was produced in E. coli cells from the cloned genes allowing for some "engineering" of the proteins. A ten-histidine "tag" was added at the N termini of the P subunits so that the complex could be "glued" to a microscope coverslip coated with a nickel complex with a high affinity for the His tags. The y subunit shafts protrude upward as shown in Fig. 18-16. The y subunit was mutated to replace its... 

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