Tracer studies chemistry

Isab, A.A., Shaw, C.E. Ill and Locke, J. (1988) GC-MS and oxygen-17 NMR tracer studies of triethylphosphine oxide formation from auranofin and water- O in the presence of bovine serum albumin an in vitro model for auranofin metabolism. Inorganic Chemistry, 27, 3406-3409. 

Thus we shall be concerned with properties that furnish information about the nature of the ligands, the oxidation state of the metal, and the geometry of the field of ligands. Techniques such as radio-isotope tracer studies, neutron-activation analysis, and electron microscopy are powerful methods for locating a metal within constituents of the cell and are particularly suited to heavy-metal rather than organic drugs but since they do not provide information about the chemical environment of the metal they will not concern us here. After each section below we shall give an example, not necessarily from platinum chemistry, where the method has been used with success in biochemistry. 

Figure 9.25 Tracer studies on tau protein (a) ID gel, (b) 65Cu/63Cu isotope ratios in gel bands measured by LA-ICP-MS, (c) MALDI-FTICR mass spectrum of splice isoform tau F (). Su. Becker, M. Zoriy, M. Przybylski, ]. S. Becker, ]. Anal. At. Spectrom., 22, 63 (2007). Reproduced by permission of the Royal Society of Chemistry.)...

Peppard, D.P., Mason, G.W., Driscole, W.J., Sironen, RJ. 1958. Acidic esters of orthophosphoric acid as selective extractants for metallic cations. Tracer studies. Journal of Inorganic Nuclear Chemistry 7(3) 276-285. 

Interestingly, in the field of transition-metal complex chemistry, examples of O—N bond fission occur in the hydrolysis of nitrite complexes [e.g. as in (42) Klimek et al., 1972]. Tracer studies as well as stereochemical experiments... 

The chemistry of krypton is much more limited, with fewer than a dozen compounds reported to date. The only neutral halide is KrF2. Reports of other krypton com pounds are sparse two examples are [F—Kr—N=CH] AsF6 and Kr(OTeF5)2. The radioactivity of radon has made the study of its chemistry difficult RnF2 and a few other compounds have been observed through tracer studies. 

The main uses of deuterium are in tracer studies to follow reaction paths and in kinetic studies to determine isotope effects. " A good discussion with appropriate references is in Comprehensive Inorganic Chemistry, Vol. 1, pp. 99-116. The use of deuterated solvents is widespread in proton nmr studies to avoid interference from solvent hydrogen atoms, and deuteriated compounds are also valuable in structural studies involving neutron diffraction techniques. 

Our knowlege of its chemistry is based mainly on tracer studies, which sho v that it behaves about as one might expect by extrapolation from the other halogens. The element is rather volatile. It is somewhat soluble in water from which it may, like iodine, be extracted into benzene or carbon tetrachloride. It cannot, like iodine, be extracted from basic solutions. 

Among the tools used to study reaction mechanisms, the replacement of an atom by one of its isotopes has proven unique in its efficiency. In organic chemistry, which is mostly concerned with carbon and hydrogen containing compounds, replacing protium with deuterium has frequently been used, especially in tracer studies, to follow reaction paths and in kinetic studies and to determine isotope effects on reaction rates. In nature, hydrogen is essentially composed of atoms in which the nucleus is a single proton. However, it contains 0.0156% of deuterium, in which the nucleus also contains a neutron. A major source of deuterium is heavy water, D2O, which is prepared on industrial scale by the electrolytic enrichment of normal water. 

Dehydrocyclisation of alkanes to aromatic compounds is one of the basic reactions of naphtha reforming, which is one of the most important industrial catalytic processes. IThe nature of the ring closure step is one of the main questions of understanding the chemistry of dehydrocyclisation. Sharan reviewed earlier work on tracer studies of this reaction.[ 1 An excellent discussion on the development of ideas and the role of [ C] isotope in elucidating reaction pathways has been published by Davis.Two basic ideas have competed in Scheme 2. One assumed stepwise dehydrogenation of open-chain alkanes then cyclisation as one of... 

The chemistry and biochemistry of rubber have been investigated extensively, but there are still many unresolved questions. Research on the in vitro biosynthesis of rubber by Hevea latex was especially active in the 1960s [reviewed by Mullins (1%5), Lynen (1%7,1%9), and Archer and Audley (1967, 1973)]. Hepper and Audley (1969) found that up to 50% of the physiological isomer of [3- C]HMG-CoA and 97% of administered IPP were incorporated into rubber by isolated latex. Labeled acetate and MVA were also shown to serve as rubber precursors (Archer and Audley, 1973). Most of the tracer studies have involved the extension of rubber molecules via IPP, taking place on the surface of rubber particles (Archer and Audley, 1973). However, there is evidence that DMAPP stimulates rubber biosynthesis in the presence of washed rubber particles (Lynen, 1%9 Archer and Audley, 1973). This is consistent with the anticipated role of DMAPP as a chain initiator, but the questions of chain initiation and chain termination, and the nature of the rubber particles as organelles, do not appear to have been resolved. It is assumed (Archer and Audley, 1973) that the starter end of the rubber molecule bears an isopropylidene group, and the other end a pyrophosphate group. 

Considerable further contributions to the understanding of the chemistry of nitrosyl chloride solutions have been provided by the results of tracer studies o- using 36C1. The exchange was studied between nitrosyl chloride and the dissolved chlorides of aluminium(III), gallium(III), indium(III), thallium (III), iron(III) and antimony(V). Rapid exchange was found and it was concluded that the chlorine... 

Tritium ( H or T) finds wide application in tracer studies in chemistry, biochemistry, and medicine (1), as reference to Chemical Abstracts demonstrates (2). This is largely because tritium is an isotope of hydrogen and has a radioactive nucleus with a convenient half-life of 12,35 y. The decay product is He. 

Bentley, R., Thiessen, C.P., 1957. Biosynthesis of itaconic acid in Aspergillus terreus. I. Tracer studies with C14-labeled substrates. Journal of Biological Chemistry 226,673-687. 

All isotopes of element 85, astatine, are intensely radioactive with very short half-lives (p. 795). As a consequence weighable amounts of the element or its compounds cannot be prepared and no bulk properties are known. The chemistry of the element must, of necessity, be studied by tracer techniques on extremely dilute solutions, and this introduces the risk of experimental errors and the consequent possibility of erroneous... 

The only respect in which the hot atom chemistry of organometallic compounds has so far been applied to other fields of study is in the area of isotope enrichment. Much of this has been done for isolation of radioactive nuclides from other radioactive species for the purpose of nuclear chemical study, or for the preparation of high specific activity radioactive tracers. Some examples of these applications have been given in Table II. The most serious difficulty with preparation of carrier-free tracers by this method is that of radiolysis of the target compound, which can be severe under conditions suited to commercial isotope production, so that the radiolysis products dilute the enriched isotopes. A balance can be struck in some cases, however, between high yield and high specific activity (19, 7J),... 

Since the discovery of the first noble gas compound, Xe PtF (Bartlett, 1962), a number of compounds of krypton, xenon, and radon have been prepared. Xenon has been shown to have a very rich chemistry, encompassing simple fluorides, XeF2> XeF, and XeF oxides, XeO and XeO oxyf luorides, XeOF2> XeOF, and Xe02 2 perxenates perchlorates fluorosulfates and many adducts with Lewis acids and bases (Bartlett and Sladky, 1973). Krypton compounds are less stable than xenon compounds, hence only about a dozen have been prepared KrF and derivatives of KrF2> such as KrF+SbF, KrF+VF, and KrF+Ta2F11. The chemistry of radon has been studied by radioactive tracer methods, since there are no stable isotopes of this element, and it has been deduced that radon also forms a difluoride and several complex salts. In this paper, some of the methods of preparation and properties of radon compounds are described. For further information concerning the chemistry, the reader is referred to a recent review (Stein, 1983). 

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