Bismuth, coupling

Bi is detected in alkaline medium by stannite anions. Therefore, bismuth stands in the solution as bismuth hydroxide Bi(OH)3. At pH= 14, the involved bismuth couple is Bi(OH)3/Bi(s) according to the half-redox reaction... 

Jeronimo P., Araujo A., Montenegro M., Satinsky D., Solich P., Colorimetric bismuth determination in pharmaceuticals using a xylenol orange sol-gel sensor coupled to a multicommutated flow system, Anal. Chim. Acta. 2004 504 235-241. 

Berndt et al. [740] have shown that traces of bismuth, cadmium, copper, cobalt, indium, nickel, lead, thallium, and zinc could be separated from samples of seawater, mineral water, and drinking water by complexation with the ammonium salt of pyrrolidine- 1-dithiocarboxylic acid, followed by filtration through a filter covered with a layer of active carbon. Sample volumes could range from 100 ml to 10 litres. The elements were dissolved in nitric acid and then determined by atomic absorption or inductively coupled plasma optical emission spectrometry. 

Tseng et al. [69] determined 60cobalt in seawater by successive extractions with tris(pyrrolidine dithiocarbamate) bismuth (III) and ammonium pyrrolidine dithiocarbamate and back-extraction with bismuth (III). Filtered seawater adjusted to pH 1.0-1.5 was extracted with chloroform and 0.01 M tris(pyrrolidine dithiocarbamate) bismuth (III) to remove certain metallic contaminants. The aqueous residue was adjusted to pH 4.5 and re-extracted with chloroform and 2% ammonium pyrrolidine thiocarbamate, to remove cobalt. Back-extraction with bismuth (III) solution removed further trace elements. The organic phase was dried under infrared and counted in a ger-manium/lithium detector coupled to a 4096 channel pulse height analyser. Indicated recovery was 96%, and the analysis time excluding counting was 50-min per sample. 

It is seen by examination of Table 1.11(b) that a wide variety of techniques have been employed including spectrophotometry (four determinants), combustion and wet digestion methods and inductively coupled plasma atomic emission spectrometry (three determinants each), atomic absorption spectrometry, potentiometric methods, molecular absorption spectrometry and gas chromatography (two determinants each), and flow-injection analysis and neutron activation analysis (one determinant each). Between them these techniques are capable of determining boron, halogens, total and particulate carbon, nitrogen, phosphorus, sulphur, silicon, selenium, arsenic antimony and bismuth in soils. 

The above experimental results strongly support a ligand-coupling mechanism [62, 63] for bismuth(V)-assisted a-alkenylation. Thus, the enolate attacks the... 

Cyclic triarylbismuth(III) compounds also undergo the Pd-catalyzed cross-coupling reaction with benzoyl chloride (Scheme 27) [42]. The exocyclic aryl group was selectively transferred to form 4-methylbenzophenone in good yield. Bismuth-containing products could not be isolated except for the cyclic bismuth compound possessing a SO2 moiety, for which cyclic bismuth chloride was isolated in 86% yield. 

Aryl chlorides can also be used as coupling partners for azabismocine reagents 2. In the coupling reaction with aryl chlorides, Pd(PPh3)4 was not an efficient catalyst, and Pd(OAc)2/l,l,-bis(diphenylphosphino)ferrocene (dppf) combination was found to be effective [54]. Not only the arylation, but also methylation, alkenylation and alkynylation reactions can be accomplished by using the corresponding bismuth compounds (Scheme 35). The addition of CsF improved the product yields. However, electron-rich aryl chlorides were unable to be coupled efficiently under these reaction conditions. 

A recent report has shown that tricyclopropylbismuth can be utilized in the cross-coupling reaction with aryl halides and triflates [57]. Representative examples are shown in Scheme 38. Addition of a base activator and excess of the bismuth reagents are necessary to obtain the coupling products in good yields, although more than one cyclopropyl group was transferred when 0.5 equivalents of... 

The cross-coupling reaction of homoallylic alcohols with aldehydes in the presence of bismuth trichloride in solvent-free conditions under microwave irradiation generated 4-chloro-2,6-disubstituted tetrahydropyrans with high c/.v-diastereos-electivity [15]. The reaction of benzaldehyde with l-phenyl-3-buten-l-ol in the presence of bismuth trichloride under microwave irradiation gave the corresponding... 

M. Grotti, C. Lagomarsino and R. Frache, Multivariate study in chemical vapor generation for simultaneous determination of arsenic, antimony, bismuth, germanium, tin, selenium, tellurium and mercury by inductively coupled plasma optical emission spectrometry, J. Anal. At. Spectrom., 20(12), 2005, 1365-1373. 

G. J. Burch and Y- H. Yeley found that when the metals, copper, silver, bismuth, and mercury are introduced into purified nitric acid of varying degrees of concentration, and a couple made with platinum, the electromotive force of such a cell increases considerably until it reaches a constant and (in most cases) a maximum value. This rise of electromotive force is attributed to the production of nitrous... 

As mentioned earlier, the multicomponent oxide catalysts currently commercialized contain bismuth, iron, and molybdenum, in addition to several other cations. Although few reports concerning multicomponent catalysts have appeared in the literature, there is agreement that iron affects several aspects of the catalyst system. Measurements on multicomponent catalysts by Wolfs et al. (109-111) showed that Fe3+ was partially reduced to Fe2+ after the catalytic reaction, indicating that Fe3+ ions are involved in the reaction mechanism. The observed Fe3+/Fe2+ redox couple was associated with the increased activity of the catalyst. 

The present chapter reviews recent research efforts aimed at developing new devices for in situ and on-site electrochemical stripping analysis of trace metals. It is not a comprehensive review, but rather focuses on new tools for decentralized metal testing, including remotely deployed submersible stripping probes, hand-held metal analyzers coupled with disposable microfabricated strips, and newly developed green bismuth film sensors. 

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