A Relation between Rate Constant for the Ligand Substitution and Substitution Reactivity in the Technetium and Rhenium Complexes

在合成同位素标记的放射性药物的基础上，用动力学方法研究了配合物的配体取代反应。在氚配合物的合成中，需要用分光光度的方法来测定。所有提出的方法都包括还原高铁酸盐和配体取代的过程。用高铁酸盐萃取三(1，10-邻菲咯啉)铁(II)，建立了一种新的、简便的光度测定锶的方法。采用氯化四氯砷(TPAC)萃取法，建立了四氯氮杂环己酸酯(VI)的水解反应机理。在有机相中存在3，5-二氯苯酚时，未发现四氯氮杂环己酸酯(VI)中的TC*N键反式作用。在乙腈溶液中，双(乙酰丙酮基)氮化锶(V)的碱解反应动力学研究表明，乙腈取代乙酰丙酮后，氢氧根离子的侵袭发生了。最后，通过碱解完全分解了乙酰丙酮络合物，并测定了这些复杂过程的速率常数。以硫脲、二甲基硫脲和二乙基硫脲为原料，从动力学角度研究了六价(硫脲衍生物)锶(III)离子的生成机理。本文还研究了六价(硫脲)锶(III)离子与二乙三胺五乙酸(DTPA)的反应动力学。比较了六价(硫脲)Re(III)的碱解和六价(硫脲)Te(III)的碱解。在此基础上，综述了1996年在莫斯科举行的首届俄日氚研讨会上的氚络合物的取代反应。

The ligand substitution of the complexes of technetium and rhenium was kinetically investigated based on the syntheses of radiopharmaceuticals labeled with technetium and rhenium radioisotopes.In the synthesis of technetium complex, photometric determination of technetium is required. All the methods proposed included the process of reduction of pertechnetate and ligand substitution. Consequently, a new and simple method for the spectrophotometric determination of technetium has been developed by means of the solvent extraction of tris(1,10-phenanthroline)iron(II) with pertechnetate into nitrobenzene. Mechanism of hydrolysis of tetrachloronitridotechnetate(VI) was established by means of the solvent extraction with tetrachloroarsonium chloride(TPAC). In the presence of 3,5-dichlorophenol in the organic phase, no trans-effect of Tc*N bond in tetrachloronitridotechnetate( VI) was found. No synergestic effect can be explained by the formation of an ion pair of TPAC and DCP.Kinetic investigation of the base hydrolysis of bis(acetylacetonato)nitridotechnetium(V) was done in an acetonitrile solution, showing that the replacement of an acetonitrile for the acetylacetonate was followed by the attack of hydroxide ion. Finally the acetylacetonate complex was fully decomplsed by the base hydrolysis and the rate constants for these complicated processes were determined. Formation mechanism of hexakis(thiourea derivative)technetium(III) ion from pertechnetate was studied kinetically using thiourea, dimethylthiourea and diethylthiourea. The reaction of hexakis(thiourea)technetium(III) ion with dietylenetriaminepentaacetic acid (DTPA) was also studied kinetically. Base hydrolysis of hexakis(thiourea)rhenium(III) was compared with that of hexakis(thiourea)technetium(III). On the basis of these results, the substitution reactions of technetium complexes was reviewed at the First Russian-Japanese Seminar on Technetium held in Moscow, 1996.