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  • Author or Editor: D. Gambino x
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Abstract  

A series of Tc/V/ cationic complexes was synthesized by electrochemical reduction of TcO 4 . The electrolysis was performed in aqueous media containing amines as ligands: en, dien, trien and 1,3-dap*. The combination of different techniques allows to propose the general formula [TcO2/amine/2]+ for these compounds. Electrodeposition of TcO2 was a competitive reaction. The UV spectra were compared with those for other Tc/V/ amine complexes. The presence of two peaks, one in the range 303–312 nm and the other in 230–240 nm, could be verified. The latter was markedly sensitive to pH changes. Preliminary studies showed that kinetic stability decreases in the sequence en, 1,3-dap, trien, dien. The decomposition rate increased when the pH was lowered.

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Abstract  

Electrolytic pertechnetate reduction at inert electrodes was studied as an alternative procedure for synthesizing Tc complexes. Pertechnetate reduction was carried out in aqueous media using different aminated ligands /en, dien, trien and 1,3-dap/ forming [TcO2/amine/2]+ type complexes. Simultaneously with synthesis of the desired Tc complex, TcO2 was electrodeposited onto the cathode. Conversion of TcO 4 to Tc complex and TcO2 was studied as a function of several variables /kind and concentration of supporting electrolyte, ligand concentration, pH, current and electrolysis time/.

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Abstract  

Electrolytic reduction of pertechnetate was performed in aqueous solution containing -acceptor ligands. Cyanide and 1,10-phenanthroline were the selected ligands. In both cases, electrolyses produced a cathodic TcO2 deposit and soluble Tc complexes. When cyanide was the ligand, the complexes formed were [Tc (CN)6]5– and [TcO2 (CN)4]3–. When working with the amine, [Tc (phen)3]2+ and another positively charged species were found after reaction. Results are compared with previous studies with amines, and the usefulness of the electrolytic route to obtain Tc complexes is evaluated.

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Abstract  

The strong chemical resemblance between Tc and Re is applied to design and evaluate experiments with99mTc complexes. A combination of spectrophotometric and electrophoretic techniques allows to propose the formula [TcO2/amine/2]+ for compounds prepared by reduction of99mTcO 4 with Zn /solid phase/ in presence of several /bidentate/ amines.

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Abstract  

Ligand exchange is one of the possible synthetic routes to obtain99mTc coordination compounds. However, the success of this route depends on the availability of good precursors. The objective of this work is the preparation of the complex [99mTc(tu)6]3+ (tu = thiourea), as a potential precursor for99mTc(III) coordination compounds. The preparation was successfully performed in acidic conditions, the excess of tu serving as reducing agent. At pH values higher than 3, the compound becomes unstable and on addition of polydentate ligands new Tc(III) complexes are formed. With edta, the complex99mTc(III)-edta was obtained in high yield.

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