Organometallic reagents cadmium

OTHER ORGANOMETALLIC REAGENTS (see also Carbonylation, Fluorination, Reformatsky reaction) with acids and acyl derivatives with acid halides Benzylchlorobis(triphenyl-phosphine)palladium(II), 30 Cadmium, 60... 

Tetrafluoropyridyl organometallic reagents can be prepared by reaction of 4-bromotetra-fluoro- or tctrafluoro-4-iodopyridine with zinc or cadmium in dimethylformamide at room temperature.83 Metathesis of these reagents with copper(l) bromide affords the (2.3,5,6-tetra-fluoro-4-pyridyl)copper reagent. The latter species undergoes high-yield substitution reactions with allyl halides, vinyl iodides, aryl iodides, and alkanoyl halides. 

Usually, less nucleophilic organometallic reagents such as tin (26 or 27 ), zirconium (28 ) and cadmium have been used for selective transmetallation (equations 36 , 37 , 38 and 39 ). CgHjSiFs has been used to prepare (CgH5)2SbF from SbFs (equation 40) . 

Less nucleophilic organometallic reagents, such as derivatives of tin , zirconium lead and cadmium , have usually been used for selective transmetallation (equations 65 , 66 , 67 and 68 ). Enamines have also been used (equation 69) . 

There are two ways round this problem. One is to use a less reactive organometallic reagent which reacts with acid chlorides but not with the less reactive ketones. Cadmium is a good metal for this purpose and the reagents (2) can be made from Grignard reagents or organolithiums. 

In 1993, another milestone in the preparation of II-VI semiconductor nanocrystals was the study of Murray, Norris and Bawendi [12], whose synthesis was based on the pyrolysis of organometallic reagents such as dimethyl cadmium and trioctylphosphine selenide, after injection into a hot coordinating solvent. This approach provided a temporally discrete nucleation and permitted a controlled growth of the nanocrystals. The evolution of the absorption spectra of a series of CdSe crystallites, ranging in size from about 1.2 to 11.5 nm, is shown in Figure 3.11. 

Zinc, Cadmium, and Mercury.—Slurries of finely divided Cd or Zn, formed by codeposition of the appropriate metal vapour with a solvent, are active enough to form organometallic reagents (presumed to be metal dialkyls) by reaction with simple alkyl halides. Not only a-bromoesters, but also a-bromoketones, can be reacted with Zn to give Reformatsky-like reagents. Subsequent reaction with an... 

Perfluorovinyl Cadmium Reagents. In order to achieve the formation of the F-vinyl copper reagent in the absence of F-vinyl halide, we turned to the formation of a F-vinyl organometallic reagent that does not readily couple witii vinyl halides. We... 

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