Nickel II bromide

A solution of tri(p-methoxymethyl)phenylphosphine (0.500 g, 1.26 mmol) in dry methanol (5 ml) was placed in a pressure tube with a Teflon needle valve along with p-(methoxymethyl)bromoben-zene (0.255 g, 1.26 mmol) and anhydrous nickel(II) bromide (0.007 g, 0.032 mmol). The tube was flushed with dry nitrogen and closed. The tube was maintained in an oil bath heated at 180°C for 48 h. After cooling to room temperature, the solvent was evaporated under reduced pressure to give the crude product, which was purified by flash chromatography on silica gel (50 g) using 1 1 acetonitrile ethanol as eluent. In this manner was isolated pure tetra(p-methoxymethyl)phenylphosphonium bromide (0.050 g, 7%), which exhibited spectra and analyses in accord with the proposed structure. 

Transmetallation from an early to a late transition metal is kinetically accessible and, most often, thermodynamically favorable. Treatment of 1,9-anthracendiyl zirconocene 36 with bis(triphenylphosphine)nickel(ii)bromide in the presence of diphenylacetylene gives 1,2-diphenylaceanthrylene in good yield (Equation 11), suggesting that the transmetallation of zirconium to nickel proceeds efficiently <2000JA9880>. 

An interesting reagent is Li2NiBr4, prepared from anhydrous lithium bromide and nickel(II) bromide. It reacts with epoxides regio- and stereoselectively (equation 182)1121. 

Dibrom-ethen liefert bei 160° 80% Ethen-1,2-diphosphonsaure-tetraethyl-ester394 1-Brom- zu 46% l-Brom-2-phenyl-ethen zu 52% [160°, Nickel(II)-bromid-Katalyse] 1 -Phenyl- bzw. 2-Phenyl-ethenphosphonsaure-diethylester393. Un-ter ahnlichen Bedingungen liefert Palladium(II)-chlorid als Katalysator etwas geringere Ausbeuten, die Reaktion scheint jedoch stereospezifisch zu verlaufen395. 

Procedures for the preparation of nickel(II) chloride dihydrate and nickel(II) bromide dihydrate follow. From these, the preparation via the orthoformate ester dehydration route of the anhydrous tetrakis(ethanol) and 1,2-dimethoxyethane complexes is described. The preparation of nickel(II) iodide-bis(l,2-dimethoxyethane) from nickel(II) iodide pentahydrate is also given. 

These cyclophane ligands - featuring two carbene and two pyridine donor groups - do act as tetradentate ligands towards transition metals. Baker et al. [67] reported the respective nickel(II) complex after reaction of the free ligand (bis-imidazolium salt) with nickel(II) bromide in the presence of sodium acetate as base. 

Wolf et al. used the phosphino functionalised imidazolium salt to react it with nickel(II) bromide forming the P-coordination product (see Figure 3.95). Attempts to deprotonate... 

An oxidizing system which uses bromine in the presence of carboxylate salts of nickel(II) has been studied in some detail, and supersedes the analogous procedure which uses dibenzoyl peroxide in the presence of nickel(II) bromide. In some unsymmetrical cases the selectivity is somewhat dependent on... 

The B(5)-acetyl complex [( -Cp )Co(Et2C2B3H4-5-COMe)j (91JA680) can be deprotonated with //-butyl lithium and then react with nickel(II) bromide to yield the tetradecker 7 (ML = = Co(/y -Cp ), M = Ni,... 

Naphthacenequinones, 19, 439 Naphthalene oxides, 130 Naphthazarin, 56, 57 Naphthohydroquinones, 368 1,4-Naphthoquinone, 18-19, 289 1-a-Naphthylethylamine, 320-321 1-(1-Naphthyl)ethyl isocyanate, 321 Nazarov reaction, 314, 499 Nerolidol, 292 Neryl acetate, 388 Nickel-Alumina, 321-322 Nickel boride, 190 Nickel(II) bromide, 136 Nickel(II) bromide-Zinc, 322 Nickel peroxide, 322-323 Nishimura catalyst, 408... 

On treatment with aqueous silver nitrate it forms a stable crystalline complex (78), from which 75 can be recovered almost quantitatively by addition of ammonia ". Anhydrous nickel(ii) bromide converts cyclooctyne into the trimer (79) with a quantitative yield . However, when the reaction was carried out in the presence of a trace of water, the dimeric cyclobutadiene-nickel bromide complex (80) was obtained in 9-4% yield, together with 79 (85%) . The spectroscopic properties of 80 showed close similarity with those of the tetramethylcyclobutadiene-nickel chloride complex . 

Na2AsHl5011 sodium hydrogen arsenate heptahydrate 10048-95-0 25.00 1.8700 1 3097 NiBr2 nickel (ii) bromide 13462-88-9 25.00 5.1000 1... 

A phosphine-based nickel(II) bromide complex (Ni-2) also induces living radical polymerization of MMA specifically when coupled with a bromide initiator in the presence of Al(0-i-Pr)3 as an additive in toluene at 60 and 80 °C.133 The reaction rates and the effects of radical inhibitors are similar to those with Ni-1, whereas chloride initiators are not effective in reaction control. Additives are not necessary when the polymerization is carried out in the bulk or at high concentrations of monomer, either methacrylate or /v-butyl acrylate (nBA).134 An alkylphosphine complex (Ni-3) is thermally more stable and can be employed for MMA, MA, and nBA in a wide range of temperatures (60—120 °C) without additives.135 A fast polymerization proceeds at 120 °C to reach 90% conversion in 2.5 h. A zerovalent nickel complex (Ni-4) is another class of catalyst for living radical polymerization of MMA in conjunction with a bromide initiator and Al(0-i-Pr)3 to afford polymers with narrow MWDs MJMn = 1.2—1.4) and controlled molecular weights.136 The Ni(0) activity is similar to that of Ni(II) complexes whereas the controllability... 

The easily available 1-bromo-l-seleno aUcene, by treatment with sodium phenyl tellurolate under bis(bipyridine)nickel (II) bromide catalysis, furnishes the corresponding telluro(seleno)ketene acetal. " ... 

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