Nickel ethylenediamine

Iron (III) chloride solution Nickel ethylenediamine nitrate [Ni(NH2(CH2)2NH2)3](N03)2... 

Nickel ethylenediamine nitrate reagent [Ni(NH2.CH2.CH2.NH2)3](N03)2, abbreviated to [Ni(en)3](N03)2. When a neutral or slightly alkaline solution of a thiosulphate is treated with the reagent, a crystalline, violet precipitate of the complex thiosulphate is obtained ... 

The nickel ethylenediamine nitrate reagent is conveniently prepared when required by treating a little nickel chloride solution with ethylenediamine until a violet colour (due to the formation of the complex [Ni(en)3]2+ ion) appears. Concentration limit 1 in 25,000. 

Thiosulphate, (i) Action of dilute H2S04 upon solid, and liberation of S02 (dichromate paper test or fuchsin solution test) and sulphur (IV.5, 1). (ii) Potassium cyanide test (IV.5, 6). (iii) Nickel ethylenediamine test (IV.5, 9). 

Figure 3.4 nickel ethylenediamine complex reacts with acetone to form a nirrin, the four planar positions of the JVz " " bonds templating the reaction. In evolutionary terms, such reactions permitted great strides forward, as simple molecules such as the two above immediately became corrins surrounding the cobalt of vitamin B12 chlorophyll if magnesium and haem if ferrous was at the centre (from R.W. Hay, in An Introduction to Bio-inorganic Chemistry , ed. D.R. Williams, by permission of the Publishers,... 

Nickel ethylenediamine nitrate reagent. This reagent should be prepared when required from 2 ml 0.5m nickel chloride solution by adding ethylenediamine dropwise, until a violet colour appears. The colour is due to the formation of the complex ion [Ni(NH2-CH2-CH2-NH2)3] ". ... 

Preparation of small metal nickel particles supported on silica using nickel ethylenediamine precursors... 

In this section, the effect of aggregates such as metallomicelles comprised of nickel and hydrophobic diamines on the epimerization of aldoses is outhned. A homologous series of nickel/ethylenediamine complexes of various N,N-dime-thyl-N -alkylethylenediamines (l,l,n -en) was prepared and examined [64], The influence of the hydrophobicity of the Hgand on the epimerization in aqueous media was assessed. The objective of this work was to clarify why differences in hydrophobicity affect the outcome of the epimerization and to characterize the nature of the aggregative metallomicelle. 

It has been known for a long time that thiosulfate is present in normal human urine, but reliable methods for the determination of fairly low concentrations have not been available. A method based on the precipitation of the nickel-ethylenediamine complex of thiosulfate followed by iodometric determination was reported many years ago, but gives according to our experience unreliable results. We have earlier described a simple colorimetric method for determination of thiosulfate, based on the cyanolysis of thiosulfate to thiocyanate by the action of cyanide and cupric ions followed by determination of thiocyanate as its ferric ion complex. Unfortunately, this method is not sensitive enough for direct application to urine and, furthermore, other urinary compounds interfere in the cyanolysis reaction. It may, however, be used for assay of the very... 

EDA and other alkylene amines react readily with acrylonitrile or acrylate esters. EDA reacts with acrylonitrile to give tetrakis(2-cyanoeth5i)-ethylenediamine which is reduced over Raney nickel to give tetralds(3-anainoprop5i)-ethyl-enediainine (52). With methyl acrylate and EDA under controlled conditions, a new class of starburst dendritic macromolecules forms (53,54). 

Highly stereospecific hydrogenations of acetylenes to cis olefins have been achieved also with nickel (P 2) catalysts in the presence of ethylenediamine as prorrtoter (37 8 55 58,72). The catalyst is prepared by reduction of nickel acetate in ethanol with sodium borohydridefi ). Despite successes (44), the use of nickel is relatively infrequent (51). 

In 1965, Breslow and Chipman discovered that zinc or nickel ion complexes of (E)-2-pyridinecarbaldehyde oxime (5) are remarkably active catalyst for the hydrolysis of 8-acetoxyquinoline 5-sulfonate l2). Some years later, Sigman and Jorgensen showed that the zinc ion complex of N-(2-hydroxyethyl)ethylenediamine (3) is very active in the transesterification from p-nitrophenyl picolinate (7)13). In the latter case, noteworthy is a change of the reaction mode at the aminolysis in the absence of zinc ion to the alcoholysis in the presence of zinc ion. Thus, the zinc ion in the complex greatly enhances the nucleophilic activity of the hydroxy group of 3. In search for more powerful complexes for the release of p-nitrophenol from 7, we examined the activities of the metal ion complexes of ligand 2-72 14,15). 

Template condensation reactions of the nickel(II) complex of 3,7-bis(2-aminoethyl)-l,3,5,7-tetraazabicyclo[3.3.1]nonane with formaldehyde and the appropriate primary diamines such as ethylenediamine, 1,4-butanediamine, and p-xylenediamine yield dinickel(II) complexes of bis-heptaazamacrocyclic ligands (716)-(718). Similarly, the dinuclear Ni11 complexes (719) and (720) were prepared by using [Ni(2,3,2-tet)](C104)2, formaldehyde, and NH2—(CH2)ra—NH2 ( = 2, 3, 4, 5, 6, 10) or melamine, respectively. 

Other complexes with tetraaza macrocycles have been prepared by reaction of [Au(en)2]Cl3, ethylenediamine, or nitroethane and formaldehyde, although with nitroethane an acyclic ligand was also obtained (293).1715,1716 A gold(III) complex with a hexaaza macrocycle (1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane) has been obtained by a transmetallation reaction from the nickel compound [NiL]2+ by reaction with [AuC14], 1717 The chemistry of tetraazamacrocycles in aqueous solution has been reported.1718... 

A nickel(II) species is also though to be an intermediate in the carbonyla-tion reaction of iodobenzene with (V-methylbenzaldimine and nickel carbonyl. Two addition modes of an ensuing aroylnickel(II) complex to the C=N double bond can be envisaged as routes to l-methyl-2-phenylindol-3-one and an ethylenediamine derivative (Scheme 47).7 5 The scope of this simple indole synthesis has not been assessed. 

The importance of metal coordination compounds in biological systems has led to the study of polydentate Schilf base complexes of cobalt(II), nickel(II), and copper(II) (204, 205). Dimers have been observed in the spectra of complexes of both tri- and tetradentate ligands [e.g., salicylaldehydeand A,A-bis(salicylidene)ethylenediamine]. The parent ions form the base peaks, and the spectra are characterized... 

Prystowsky SD, Allen AM, Smith RW, et al. 1979. Allergic contact hypersensitivity to nickel, neomycin, ethylenediamine and benzocaine. Arch Dermatol 115 959-962. 

In Figure C we have a comparison of some studies on tris(ethylenediamine)-nickel(II) and tris(phenanthroline)nickel(II). 

Figure C. Dissociation rates of tris(ethylenediamine)nickel(II) and tris(phenanthroline)nickeI (I I)...

Eichhom and his co-workers have thoroughly studied the kinetics of the formation and hydrolysis of polydentate Schiff bases in the presence of various cations (9, 10, 25). The reactions are complicated by a factor not found in the absence of metal ions, i.e, the formation of metal chelate complexes stabilizes the Schiff bases thermodynamically but this factor is determined by, and varies with, the central metal ion involved. In the case of bis(2-thiophenyl)-ethylenediamine, both copper (II) and nickel(II) catalyze the hydrolytic decomposition via complex formation. The nickel (I I) is the more effective catalyst from the viewpoint of the actual rate constants. However, it requires an activation energy cf 12.5 kcal., while the corresponding reaction in the copper(II) case requires only 11.3 kcal. The values for the entropies of activation were found to be —30.0 e.u. for the nickel(II) system and — 34.7 e.u. for the copper(II) system. Studies of the rate of formation of the Schiff bases and their metal complexes (25) showed that prior coordination of one of the reactants slowed down the rate of formation of the Schiff base when the other reactant was added. Although copper (more than nickel) favored the production of the Schiff bases from the viewpoint of the thermodynamics of the overall reaction, the formation reactions were slower with copper than with nickel. The rate of hydrolysis of Schiff bases with or/Zw-aminophenols is so fast that the corresponding metal complexes cannot be isolated from solutions containing water (4). 

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