H-isotope exchange

A powerful technique for establishing whether a band or a component of a band around 1650-1600 cm is associated with adsorbed water is D/H isotopic exchange. The exchange results in a red shift of the water deformation modes (for more details, see Section 6.1). Another possibility is to analyze the overtones and combination modes (see Section 7.3). 

Althoi h the equilibrium constant for hydration is unfavorable, the equilibrium between an aldehyde or ketone and its hydrate is established rapidly and can be detected by isotopic exchange, using water labeled with 0, for example ... 

Preequilibria and rate law. The rate of isotopic exchange between U(IV) and U(VI) follows a second-order rate expression at constant [H+] 24... 

Haul, RA.W. and Stein, L.H. 1955 Diffusion in calcite crystals on the basis of isotope exchange with carbon dioxide. Faraday Society Transactions 51 1280-1290. 

Xenon [ F]difluoride was synthesized by isotopic exchange between XeF2 and H F, Si F4, or As F, and F-2DFG was prepared - by the action of this reagent on tri-O-acetyl-D-glucal (61). In this reaction, the combination of ethyl ether (as the solvent) and BFj (as the Lewis acid catalyst) was found to give the best result. ... 

Iengo E, Scandola F, Alessio E (2006) Metal-Mediated Multi-Porphyrin Discrete Assemblies and Their Photoinduced Properties 121 105-143 Itoh M, Taniguchi H (2007) Ferroelectricity of SrTiC>3 Induced by Oxygen Isotope Exchange. 124 89-118... 

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... 

Attempted acetylation of 2,2, 5,5 -tetramethyl-l,l -distibaferrocene (29) or 3,3, 4,4 -tetramethyl-l,T-distibaferrocene (61) led to destruction of the ring system and the formation of intractable products. Acid-catalyzed H/D isotopic exchange (Scheme 14) is the simplest electrophilic aromatic substitution. Both l,T-diphosphaferrocene55 (7) and l,l -diarsa-ferrocene (8)13 undergo rapid exchange at the a positions when treated... 

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