| Popis: |
The value of labeling organic molecules with deuterium and/or tritium in a one-step procedure is now well established for structure determination by mass spectrometry [1], spin decoupling in nuclear magnetic resonance spectroscopy [2], evaluation of coupling constants in electron-spin resonance spectroscopy [3] and in general reaction mechanism studies [4]. Besides specific synthetic chemical methods [5, 8], the most useful general labeling procedures are gas irradiation [7] for tritium or catalytic exchange with isotopic water [8, 9] for deuterium or tritium. The advantages of heterogeneous exchange reactions in the presence of transition metals such as platinum have been critically evaluated when compared with the radiation-induced procedures [lo, 11]. A π-complex adsorption mechanism has been proposed to account for the reactivity of molecules in such heterogeneous exchange systems[12,13]. |
