Of Ni EDTA

Detection limit. Low concentrations of Ni-EDTA near the detection limit gave the following counts in a mass spectral measurement 175, 104, 164, 193, 131, 189, 155, 133, 151, 176. Ten measurements of a blank had a mean of 45 counts. A sample containing 1.00 pM Ni-EDTA gave 1 797 counts. Estimate the detection limit for Ni-EDTA. 

NMR and CD methods. (251) From the spectral data it is concluded that these complexes stereospecifically adopt the A-s-cis form(s) in solution [48]. The solution structures of a variety of EDTA-type complexes have been deduced from variable temperature studies. (306) Racemization of Ni(EDTA) and Ni(l,3-DDTA) is rapid at 80°C but is slow for the other complexes studied. The kinetic data indicate predominant 5-coordination by EDTA and 1,3-PDTA. The suggested racemization mechanism (Fig. 5) involves a 7-coordinate intermediate. 

Mixed Donors. The 4-methylpyridine adduct of bis-[l-(2-thienyl)-4,4,4-trifluoro-butane-l,3-dionato]nickel(ii) is shown to have weaker co-ordination than the nonadduct by X-ray studies. The crystal structure of bis-(8-amino-2-methylquinoline) nitratonickel(ii) nitrate shows that the nitrato ligand is bidentate (66). A kinetic study has been made of nickel(ii) murexide complex formation in DMS0-MeN02- Nickel(ii) complexes of some optically active ethylenediamine-NN -diacetic acid-type polyaminocarboxylic acids have been prepared and solid-state spectra and t.g.a. recorded. N.m.r. temperature dependence for racemization of Ni(edta) ,... 

These reactions can be also catalyzed with LDH-contained or-supported transition metal or noble metal ions (175,609). Bhattacharyya et al. found NiMgAl-oxide catalysts from their pristine LDHs are very active and selective in these two reforming reactions (609). The NiMgAl-oxide catalyst can be also made through intercalation of Ni(EDTA) into the interlayer and then calcination, showing high activity as well as stability and reusability (429). 

An alloy of chromel containing Ni, Fe, and Cr was analyzed by a complexation titration using EDTA as the titrant. A 0.7176-g sample of the alloy was dissolved in ITNOa and diluted to 250 mb in a volumetric flask. A 50.00-mb aliquot of the sample, treated with pyrophosphate to mask the Fe and Cr, required 26.14 mb of 0.05831 M EDTA to reach the murexide end point. A second 50.00-mb aliquot was treated with hexamethylenetetramine to mask the Cr. Titrating with 0.05831 M EDTA required 35.43 mb to reach the murexide end point. Einally, a third 50.00-mb aliquot was treated with 50.00 mb of 0.05831 M EDTA, and back titrated to the murexide end point with 6.21 mb of 0.06316 M Cu +. Report the weight percents of Ni, fe, and Cr in the alloy. 

EDTA forms colored complexes with a variety of metal ions that may serve as the basis for a quantitative spectrophotometric method of analysis. The molar absorptivities of the EDTA complexes of Cu +, Co +, and Ni + at three wavelengths are summarized in the following table (all values of e are in cm )... 

These reactions take place with sparingly soluble silver salts, and hence provide a method for the determination of the halide ions Cl", Br, I-, and the thiocyanate ion SCN ". The anion is first precipitated as the silver salt, the latter dissolved in a solution of [Ni(CN)4]2", and the equivalent amount of nickel thereby set free is determined by rapid titration with EDTA using an appropriate indicator (murexide, bromopyrogallol red). 

This colour change can be observed with the ions of Mg, Mn, Zn, Cd, Hg, Pb, Cu, Al, Fe, Ti, Co, Ni, and the Pt metals. To maintain the pH constant (ca 10) a buffer mixture is added, and most of the above metals must be kept in solution with the aid of a weak complexing reagent such as ammonia or tartrate. The cations of Cu, Co, Ni, Al, Fe(III), Ti(IV), and certain of the Pt metals form such stable indicator complexes that the dyestuff can no longer be liberated by adding EDTA direct titration of these ions using solochrome black as indicator is therefore impracticable, and the metallic ions are said to block the indicator. However, with Cu, Co, Ni, and Al a back-titration can be carried out, for the rate of reaction of their EDTA complexes with the indicator is extremely slow and it is possible to titrate the excess of EDTA with standard zinc or magnesium ion solution. 

Under nitrogen, 2,2 -bipyridine (0.322 g, 2.07 mmol) was added to a mixture of Ni(COD)2 (0.570 g, 2.07 mmol) in anhydrous DMF (18 mL) and the mixture was stirred at room temperature for 1 h. Then 95 (0.510 g, 1.60 mmol) was added and the reaction mixture was stirred at 60-70°C for 28 h. After cooling to room temperature, HC1 (100 mL, 2 M) was added and the mixture was stirred overnight. After filtration, the solid was washed with a mixture of MeOH (60 mL) and concentrated HC1 (10 mL), a warm aqueous solution of ethylene-diaminetetraacetic acid (EDTA) (pH 9, then pH 3), dilute ammonia, water, and MeOH repeatedly and dried under vacuum for 20 h at 80°C. Polymer 96 was obtained in 100% yield (0.261 g). Light scattering gave Mw = 5400. 

Quevauviller Ph, Herzig R. and Muntau H (1996b) Certified reference material of lichen (CRM 482) for the quality control of trace element biomonitoring. Sci Total Environ 187 143-152 Quevauviller Ph, Lachica M., Barahona E, Rauret G, Ure A, Gomez A, and Muntau H (1997) The certification of the EDTA-extractable contents (mass fractions) of Cd, Cr, Ni, Pb, and Zn and of the DTPA-extractable contents (mass fractions) of Cd and Ni in calcareous soil by the extraction procedures given CRM 600. EUR Report 17555 Quevauviller Ph. Maier EA, and Griepink B, eds. (1995) Quality Assurance for Environmental Analysis. Elsevier. Amsterdam. 

Figure 14 Molecular structure of the [Ni(edta)]2 subunit in [Ni2(edta)(H20)4] 2H20.

Ni/Al, Co/Al, Cu/Al, Rh/Mg/Al and Rh/Ni/Mg/Al catalysts obtained from LDH precursors have been investigated in CO2-reforming of CH4 [93,94]. In addition, Tsyganok et al. also found that Mg/Al LDHs intercalated with an [Ni(EDTA)] chelate complex could be used as a precursor to an efficient catalyst for the above reaction [95]. 

Even complex rate laws may be easily constructed by examining the dependence of F xch on the concentrations of the various species in solution. The rate of exchange of Ni between Ni + and Ni(edta) obeys the rate law... 

Most of the studies of the reactivity of this oxidation state have been carried out with these types of complexes. The low spin d Ni(IV) resembles Co(III) in being diamagnetic, substitution inert and capable of resolution into optical isomers. Reductions are outer-sphere when Co(edta), ascorbate and Co(phen)3+ Ref. 269 are used, intermediate Ni(III) species are detected and characterized. Oxidation of Co(edta) by Ni (S-Me2L) + or Ni (S-MejL), L = 12, R = R]=CH3i R2 = H, produces a =10% excess of (+)-... 

The total number of bonds from the ligand to the central metal ion is known as the coordination number. In the Ni -EDTA complex, the coordination number is six. 

Dissolution of goethite and ferrihydrite at pH 6 by M-EDTA (M = Pb, Zn, Cu, Co, Ni) is slower than that by EDTA alone (Nowack Sigg, 1997). Dissolution was considered to involve the formation of a ternary surface complex which then dissociated releasing M into solution after which Fe was detached from the oxide as Fe-EDTA. For ferrihydrite, the rate of dissolution depended on the nature of M, because the rate determining step was dissociation of M-EDTA. For goethite, on the other hand, this step was fast, hence the rate of dissolution was independent of M. 

Step 1. Dry metallised fibre (0.1 g) was immersed in 50 ml of H20 and 10ml of 1.5% H202 was added. It was then boiled for 20min. Buffer solution (1 ml, pH = 10) was added, and the amount of Ni(II) was determined by titration with 0.01 mol 1 1 EDTA using Hg(II) as end-point detection. Based on Equation 11.1, the amount of NiS extracted from the fibre can be calculated with Equation 11.2 ... 

An indirect AAS method was described for EDTA in the antibiotic streptomycin [42]. The method involved formation of the Ni(II) complex with EDTA, release of complexed Ni(II) by pH adjustment, and subsequent determination of Ni(II) by AAS. EDTA was also determined through its masking effect on the extraction of copper oxinate into methylisobutyl ketone at pH 6.5. The decrease in AAS signal of Cu(II) was linearly proportional to the EDTA concentration [43]. 

FIG. 5, Suggested solution structure and racemization mechanism of the Ni-EDTA complex in aqueous solution. (306)... 

A solution of NP (25.00mL) was titrated with 0.1036molL EDTA at pH 5 and required 20.25 mL for the metal-indicator to change colour. What is the concentration (gL ) of Ni The atomic weight of nickel is 58.71 gmoC. ... 

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