Cadmium complexes solvent effect

Cadmium, tris[4,4,4-trinuoro-l-(2-furyl)-l,3-butanedione]-structure, 65 Cadmium complexes equilibrium constant solvent effect, 516 Cage compounds in gravimetry, 525 Cage mechanism photochemistry, 393 Cages, 135 formation... 

At low temperatures in inert solvents (such as methylene dichloride) a controlled polymerization can be effected using various acids and alkylating agents. These initiators include boron trifluoride etherate, triethylaluminum, trityl hexachloroantimonate, triethylam-monium hexachloroantimonate, diethyloxonium hexafluoroantimonate, p-toluenesulfonic acid and diethylzinc or cadmium-1,2-dioI complexes. Crystalline, high molecular weight... 

Two 67Zn (natural abundance = 4.12% / = f) n.m.r. studies have been reported.9,10 The chemical shift of 67Zn (4.81 MHz at 1.807 Tesla) in aqueous zinc chloride, bromide, and iodide solutions was found to be strongly concentration dependent, while no such dependence was noted in solutions of the perchlorate, nitrate, or sulphate. This behaviour resembles that found for analogous cadmium systems, and is attributed to the formation of mono- and poly-halogeno- complexes even at low salt concentrations. In addition, the zinc halide solutions show an anomalous shift to higher frequencies for their solutions in D20, compared with those in H20. The perchlorate, nitrate and sulphate show no solvent isotope effect. 

Raman spectral studies of the species MX(n" 2) (n = 2—4 M = Zn, Cd, or Hg X = Cl, Br, or I) in anhydrous tributyl phosphate have been reported.24 For the MX2 molecules, sufficient metal dihalide-solvent interaction exists to suggest bent X—M—X species with C2v rather than >ooh symmetry. The effect appears most marked for zinc(n) and least marked for mercury(n), which is in accord with the Lewis acidity sequence ZnX2 > CdX2 > HgX2. A similar analysis of the anionic MX3 complexes formed from a 1 1 mixture of LiX and MX2 again demonstrates solvent interaction, and a tetrahedral C3v species is indicated, rather than the planar structure found in the solid state. Studies involving the halogeno-complexes of zinc, cadmium, and mercury in DMSO and DMF have also been reported.25,26... 

Two other features which have been found to influence the final reaction outcome are the nature of the reaction solvent and the individual metal counter ion. The effects of the first are varied, and the latter is also important since, for example, in reactions which involve dialkyl (2-oxoalkyl)phosphonates, lithium and magnesium ions tend to form com-plexes whereas sodium and potassium ions do not. In reactions between acetone and the anion from (prop-2-enyl)phosphonic bis(dimethylamide) and BuLi, the presence of zinc or cadmium ions alters the site of attack from only C ) to a mixture of C(,) and C ) in the ratio 3 1. Dialkyl (lithioalkyl)phosphonates which lack complexing functions may be rather unstable, or may dimerize within minutes at 0... 

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