Zinc compounds, organo

Transition metal compounds with covalent carbon-metal bonds include organo-zinc, organo-cadmium, and organo-mercury compounds. Carbon-13 shifts of the methyl derivatives (Table 4.71) indicate a heavy atom deshielding. Diphenylmercury displays carbon shifts similar to those of phenyllithium and phenylmagnesium bromide (Table 4.53). 

Chromium (III) chloride forms adducts with a variety of donor ligands. The tetrahydrofuran complex CrCl3-3THF, which is obtained as violet crystals by action of a little zinc on CrCl3 in THF, is a particularly useful material for the preparation of other chromium compounds such as carbonyls or organo compounds, as it is soluble in organic solvents. 

A transmetalladon to titanium derivatives also pxtmotes the addition of various zinc organo-metallics to carbonyl compounds. However, the functional group tolerance seems to be limited (see Scheme 10). 3,47 interestingly, diethylzinc reacts with aromatic 1,2-diketones to give a-ethoxy ketones (see equation 10). ... 

Synergistic Mixture Zinc Stearate and Organo Compounds as Secondary Stabilizers. From the previous results, it is clear that in order to prevent PVC cross-linking and to increase the action time of stabilizer (previously defined with the Brabender plasticorder (1,3,4,6,7)), it is necessary to impede zinc chloride accumulation in the polymer. 

In their complexes, Zn, Cd and Hg commonly have coordination numbers four, five and six, with five especially common for zinc.1 While the coordination number for all three elements in organo compounds is usually two, only Hg commonly forms linear bonds in other cases, for example in HgO. Indeed, linear 2-coordination is more characteristic for Hg(n) than for any other metal species. 

Alkylating agents that have been used include organo compounds of alkali metals, magnesium, aluminum, mercury, and zinc. The following equations illustrate some examples ... 

The zinc alkyls, of which this is an example, are vile-smelling inflammable liquids. They were the first organo-metallic compounds prepared by Frankland in 1849. With water, they decompose giving an alkane ... 

Silicone fluids containing Si—H groups are also used for paper treatment. The paper is immersed in a solution or dilute emulsion of the polymer containing either a zinc salt or organo-tin compound. The paper is then air-dried and heated for two minutes at 80°C to cure the resin. The treated paper has a measure of water repellency and in addition some anti-adhesive properties. 

Reactions of allylzinc halides with carbon nucleophiles are rare examples of uncatalyzed transformations of organo-zinc compounds. Allylzinc bromide, formed in situ, reacted with a number of structurally diverse acyl chlorides furnishing the corresponding ketones 222 in high yields (Scheme 129).330 No isomerization to the corresponding a,(3-unsaturated ketones was observed under the conditions used (RT, 5min-6h). 

The pure compound is a pale yellow, nearly odourless oil, soluble in organic solvents, but almost insoluble in water. Averell and Norris2 describe the detection of minute quantities of parathion (20 /ig.) in spray and dust, by reduction with zinc, diazotization and coupling with an amine to give an intense magenta colour. It is effective (at concentrations of 25-600 p.p.m.) against many insect species, but of course, like the majority of organo-phosphorus insecticides, it is toxic to man and to animals. 

III. By the action of the zinc compounds of the monad positive radicals upon the haloid compounds, either of the metals themselves, or of their organo derivatives. 

Support-bound transition metal complexes have mainly been prepared as insoluble catalysts. Table 4.1 lists representative examples of such polymer-bound complexes. Polystyrene-bound molybdenum carbonyl complexes have been prepared for the study of ligand substitution reactions and oxidative eliminations [51], Moreover, well-defined molybdenum, rhodium, and iridium phosphine complexes have been prepared on copolymers of PEG and silica [52]. Several reviews have covered the preparation and application of support-bound reagents, including transition metal complexes [53-59]. Examples of the preparation and uses of organomercury and organo-zinc compounds are discussed in Section 4.1. 

If the reduction is carried out in presence of alcohol at 70°—75°, azoxy-, azo-, and, in some cases, hydrazo-compounds can be obtained. These reductions take place via intermediate organo-zinc salts which decompose yielding the azoxy-compound, etc., and a double basic zinc salt of the formula, 2NH4Ci, 5Zn(OH)2. (J. C. S 123, 2466 125,1108 J. R. T. C., 1929, 43 1930, 191.)... 

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