Deuterium isotope exchange with

Winger, B.E., light-Wahl, K.J., Rockwood, A.L., Smith, R.D. (1992) Probing qualitative conformation differences of mrrltiply protonated gas-phase proteins via hydrogen/deuterium isotopic exchange with DjO. Journal of the American Chemical Society, 114 (14), 5897-5898. 

The kinetics of deuterium isotope exchange between diphenyl phosphine and t-butylthiol have been studied by H n.m.r. spectroscopy.274 A negative temperature coefficient was observed for the reaction of a perf1uoroalky1 phosphite with a fluorinated aldehyde.275 The kinetics for the reaction of alcohols with phosphoryl trichloride bore strong similarities to those of carboxylic acid derivatives.276 An interesting report desribed the solvolysis of ary 1 hydroxymethyl-phosphonates. It was shown that a phosphoryl group does not prevent carbocation formation on an immediately adjacent carbon atom.277... 

Tetralin. Therefore, either trans-Decalin was formed on the surface of the coal with deuterium from the solvent or gas, or it was formed by isomerization from cis-Decalin with accompanying isotopic exchange with a deuterium source. Because the protium content of the cis-Decalins is much greater than the trans-Decalins, cis-trans isomerization is not very important. 

Most hot spring waters have deuterium contents similar to those of local precipitation, but are usually emiched in as a result of isotopic exchange with the country rock at elevated temperatures. The magnitude of the oxygen isotope shift depends on the O-isotope composition of both water and rock, the mineralogy of the rock, temperature, water/rock ratio, and the time of interaction. 

As a consequence, benzylic protons in a- and y-alkyl groups (but not in p-positions) are acidic and in water are in equilibrium with the corresponding methylenepyrans water at pH <5. Because the symmetric y-methylenepyrans (y-anhydrobases) are more stable than a-methylenepyrans [57], the isotopic exchange with deuterium oxide proceeds about ten times faster in y than in a, and this allows the synthesis of regiospecifically deuterated alkylpyrylium salts, which can then be converted into other deuterated compounds because the reaction with nucleophiles takes place even faster [58, 59],... 

A range of variously substituted piperidines, piperazines and dialkylamines have been conveniently deuterated in a single step by isotopic exchange with deuterium oxide in the presence of an appropriate ruthenium complex catalyst.154 The isotopic exchange has been carried out efficiently in dimethylsulfoxide at positions both a and P to the NH group. 

One of the important features of D20 is its ability to undergo isotope exchange with many compounds. For example, when NH3 is placed in D20, all of the H atoms exchange rapidly with deuterium. Presumably, this is because the exchange with NH3 can proceed by interaction of D20 with the unshared pair of electrons on the nitrogen atom in an associative process that can be illustrated as... 

The suitability of the system DBr/AlBr3 for deuterium labeling is further underlined by the fact that even the C-H bonds of saturated aliphatic hydrocarbons are attacked isotope exchange with cyclohexane reaches equilibrium in somewhat more than 10 hours. 

In solution, isotopic incorporation of deuterium from deuterated solvents into metal-bound hydrogen is common, e.g., reaction of acetone-reaction occurs between the Os complex and acetone even at reflux temperature thus the isotopic exchange with acetone-isotopic exchange may therefore occur via a deprotonation/reprotonation pathway coupled with a keto-enol tautomerization. 

Multiple exchange proceeds most readily in the presence of P-C-H bonds, which can be explained by p-elimination leading to an olefin-hydrido complex either with a single metal atom or with the participation of a neighboring metal atom. The importance of intermediate complex formation with an olefin is confirmed by the absence of exchange via a quaternary carbon atom. Cyclopentane in the isotope exchange with molecular deuterium catalyzed by metals of... 

When the fissionable isotope is dissolved in deuterium oxide, the extraction column is not used directly as the deuterium will exchange with the hydrogen of the solvent. 

A last case of sonication-sensitive catalytic reactions is the hydrogen-deuterium isotope exchange observed in carbohydrates in the presence of nickel or a nickel-aluminum alloy. A good selectivity is observed, probably due to the lower temperature allowed by sonication. However, a more complex origin can be responsible for these effects, since the sonicated alloy exhibits new features such as distinct catalytic centers, and elemental redistribution within the catalyst bulk, along with more classical consequences (surface cleaning, absence of surface area... 

Since spillover phenomena have been most directly sensed through the use of IR in OH-OD exchange [10] (in addition, in the case of reactions of solids, to phase modification), we used this technique to correlate with the catalytic results. One of the expected results of the action of Hjp is the enhancement of the number of Bronsted sites. FTIR analysis of adsorbed pyridine was then used to determine the relative amounts of the various kinds of acidic sites present. Isotopic exchange (OH-OD) experiments, followed by FTIR measurements, were used to obtain direct evidence of the spillover phenomena. This technique has already been successfully used for this purpose in other systems like Pt mixed or supported on silica, alumina or zeolites [10]. Conner et al. [11] and Roland et al. [12], employed FTIR to follow the deuterium spillover in systems where the source and the acceptor of Hjp were physically distinct phases, separated by a distance of several millimeters. In both cases, a gradient of deuterium concentration as a function of the distance to the source was observed and the zone where deuterium was detected extended with time. If spillover phenomena had not been involved, a gradientless exchange should have been observed. 

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