Studies on Chemical Behavior of Technetium Atoms Implanted in Metal Acetylacetonates

Water soluble chemical species of technetium which were obtained in deuteron bombarded mixture of molybdenum and metal acetylacetonate complexes were studied by cation exchange chromatography and by gel chromatography. The result on cation exchange chromatography, just after irradiation, indicates that 99^mTc implanted directly by the ⁹⁸Mo(d, n)^99mTc reaction shows the same distribution of chemical forms as ⁹⁵Tc implanted simultaneously. However a remarkable difference of the distribution between 99mTc and ⁹⁵Tc was observed by standing after irradiation. This “time-dependent isotope effect” was ascribed to the fact that 99mTc produced by the ⁹⁹Mo decay after implantation has a strong tendency to become a chemical entity which is more easily oxidized to pertechnetate than ⁹⁵Tc. Moreover, oxidation to pertechnetate was inhibited in the absence of oxygen. This observation suggests that the charged center produced by the β^--decay of the interstitial atom plays an important role in the oxidation process. An electrostatic interaction between the positively charged interstitial and negatively charged oxygen is a possible explanation for the process.