Cadmium adducts

Most commercial sorbic acid is produced by a modification of this route. Catalysts composed of metals (2inc, cadmium, nickel, copper, manganese, and cobalt), metal oxides, or carboxylate salts of bivalent transition metals (2inc isovalerate) produce a condensation adduct with ketene and crotonaldehyde (22—24), which has been identified as (5). 

The structure of the isomeric benzo-l,2,3-thiadiazole 11.30 is unknown, but the 1 1 adduct with AsFs (11.31) has been structurally characterized. The AsFs molecule is coordinated to the carbon-bonded nitrogen atom. Cycloocteno-l,2,3-selenadiazole is an effective source of selenium for the production of semi-conductors such as cadmium selenide." ... 

In addition to systems of the above type, i.e. involving adduct formation, various other types of synergistic extraction systems are recognised and have been reviewed.4 An example is the synergistic influence of zinc in the extraction and A AS determination of trace cadmium in water.5... 

Carbene adducts of dimethylcadmium 188-190 have been obtained by simple addition of CdMe2 to the corresponding carbene at room temperature.2 9 All the three adducts have similar structures. In the case of 190, the Ccarbene-Cd bond of 2.33 A is 0.15 A longer than the Cmethyi-Cd bonds of 2.18 A (Figure 28). As a result, the cadmium atom is in a distorted trigonal-planar environment with a Cmethy -Cd-Cmethyl angle of 136°. 

The reaction of dabco (l,4-diazobicyclo[2.2.2]octane) with Me2Cd yields a 1 1 adduct 197, which adopts a linear polymeric structure (Figure 34).255 The cadmium atom is coordinated by two dabco units and two methyl carbon atoms giving rise to a distorted tetrahedral environment. Finally, the organocadmium adduct 198 (Figure 35) has been isolated from the reaction of Me2Cd with Cd[(SeP-/-Pr2)2N]2.256 The solid-state structure consists of dimeric units where each methylcadmium unit is coordinated to three selenium atoms. The geometry about the cadmium center is tetrahedral with a Cd-C distance of 2.16 A, which is comparable to that observed in other cadmium alkyl complexes. 

Metal dithiophosphinates focused recent interest due to their potential use as single source precursors for low-pressure, metal-organic chemical vapor deposition (LP-MOCVD) of metal sulfides. Thus, zinc and cadmium dithiophosphinates and their phenanthroline and bipyridine adducts were characterized and used for deposition of ZnS and CdS.85,86... 

The green phosphoric acid from a phosphoric acid plant (PAP) contains 25-30% H3PO4. The acid is heavily entrained with impurity cations, among which arsenic, cadmium, and uranium are the most toxic. In addition, anions, like chloride, fluoride, and sulfate must be considered. Selective extraction of phosphoric acid [18] as an adduct complex with TBP according to the block diagram in Fig. 14.12 has been used to produce acid of food grade. 

The cadmium salt of the 2-allyloxybenzimidazole derivative 1 reacts with various aldehydes to afford adducts 2 with high regio- and stereoselectivities. The adducts 2 are subsequently transformed into trans-vinyloxiranes 3 (I). 

Bis(trifluoromethyl)cadmium-l,2-dimethoxyethane adduct, 0587 =1= Bis(trimethylsilylmethyl)magnesium, 3099... 

Darensbourg DJ, Wildeson JR, Yarbrough JC, Reibenspies JH (2000) Bis 2,6-difluorophen-oxide dimeric complexes of zinc and cadmium and their phosphine adducts lessons learned relative to carbon dioxide/cyclohexene oxide alternating copolymerization processes catalyzed by zinc phenoxides. J Am Chem Soc 122 12487-12496... 

Zn(R-dtp)2 complexes have been characterized and their thermal stabilities investigated 173,184,190,297-299,301-305) Zn(R-dtp)2 compounds are thermally degraded to volatile olefins and non-volatile residues and this serves as the basis for gas chromatographic determination of the compounds 304,30s) Several papers describing pyrolyses of Zn(R-dtp>2 complexes have discussed mechanisms for formation of olefins, sulfides, and other products 173,184,190,298,299, 304) Dakternieks and Graddon i8s,283)35 mentioned earlier, have reported thermodynamic measurements for depolymerization and adduct formation reactions of zinc, cadmium and mercury R-dtp compounds. 

Treatment of the 2-allyloxybenzimidazole (550) with butyllithium followed by cadmium iodide generates the cadmium salt (551) which reacts in turn with an aldehyde to give selectively the a-adduct (552) (79CL1279). Such adducts are useful synthetic intermediates, for on treatment with sodium hydride they are converted into the corresponding vinyl-oxiranes (553) of trans stereochemistry (Scheme 121). 

The zinc and cadmium tellurolato complexes are air-sensitive polymeric solids14 which should be handled under inert gas. They are sparingly soluble in petroleum and chlorocarbons but readily dissolved by coordinating solvents (N,AT-dimethylformamide, dimethylsulfoxide, or pyridine). Zn(TeAr)2 forms a crystalline 1 2 adduct with 2-methyl-lH-imidazole, Zn(TeAr)2(imid)2. Heating solutions of Zn(TeAr)2 and Cd(TeAr)2 in mesitylene leads to formation of ZnTe and CdTe, respectively. H NMR Zn(TeAr)2 (DMSO-d6) <5 2.1 (s, 3H), 2.4 (s, 6H), 6.8 (s, 2H) Cd(TeAr)2 (pyridine-d5) 5 2.13 (s, 3H), 2.3 (s, 6H), 6.72 (s, 2H). 

Figure 6. Apparatus for the formation of adducts of cadmium and zinc alkyls.

The product, which at this point is bright yellow due to traces of dissolved base, is retrapped at room temperature, in vacuo, from one storage flask to another. If the product is now not completely colorless, the retrapping process is repeated. Yield 72 g (96% based on adduct, 93% based on cadmium dichloride). 

Acetylacetone la (10 mmol), metliyl vinyl ketone 2a (10 mmol) and bismuth trichloride (0.32 g, 10% mol) were mixed together without solvent in an Erlen-meyer flask and placed in a commercial microwave oven (operating at 2450 MHz frequency) and irradiated for 15 min. The reaction mixture was allowed to reach room temperature and extracted with chloroform. Removal of solvent and the residue on purification by passing through a short column of silica gel using chloroform as eluent, affords the Michael adduct 4a in 90% yield without tlie formation of any side products. Similarly cadmium iodide (10% mol) was used in place of bismuth trichloride and the corresponding Michael adduct was isolated in 85% yields. 

Bis(trifluoromethyl)cadmium—1,2-dimethoxyethane adduct, 0584 Bis(trifluoromethyl)chlorophosphine, 0594 Bis(trifluoromethyl)cyanophosphine, 1050 Bis(trifluoromethyl)dioxirane, 1052 Bis(trifluoromethyl) disulfide, 0640a... 

There exists a variety of Lewis base adducts of cadmium xanthates containing different donor atoms and ligands of varying denticity. The bis(pyridine)... 

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