Technetium complexes synthesis

Saladino R, Crestini C, Costanzo G, DiMauro E (2005) On the Prebiotic Synthesis of Nucle-obases, Nucleotides, Oligonucleotides, Pre-RNA and Pre-DNA Molecules. 259 29-68 Santos I, Paulo A, Correia JDG (2005) Rhenium and Technetium Complexes Anchored by Phosphines and Scorpionates for Radiopharmaceutical Applications. 252 45-84 Santos M, see Szathmdry E (2005) 259 167-211... 

The most convenient route to organometallic technetium complexes is directly from 3, under reaction conditions which allow working in a normal laboratory. There are basically three essential compounds that fulfil these conditions and can be prepared in a one step synthesis starting from 3, and which are convenient precursors for subsequent chemistry due to their reactivity (Scheme 1). 

Among other widely used reducers for the synthesis of binuclear technetium complexes with M-M bonds, zinc in HC1 and H3P02 [1,11] are most important. These reducers, as a rule, are used for the synthesis of Re clusters of similar structure. 

The reduction of pertechnetate with concentrated hydrochloric acid finally yields the tetravalent state, and no further reduction to the tervalent state takes place. Therefore, the tervalent technetium complex has usually been synthesized by the reduction of pertechnetate with an appropriate reductant in the presence of the desired ligand. Recently, the synthesis of tervalent technetium complexes with a new starting complex, hexakis(thiourea)technetium(III) chloride or chloropentakis(thiourea)technetium(III) chloride, has been developed. Thus, tris(P-diketonato)technetium(III) complexes (P-diketone acetylacetone, benzoyl-acetone, and 2-thenoyltrifluoroacetone) were synthesized by the ligand substitution reaction on refluxing [TcCl(tu)5]Cl2 with the desired P-diketone in methanol [28]. 

Crystals of [Tc(tu)6]Cl3 or [TcCl(tu)5]Cl2 are often employed for the synthesis of technetium(III) complexes. However, since the direct reduction of pertechnetate with excess thiourea in a hydrochloric acid solution yields [Tc(tu)6]3+ in high yield [37], direct use of the aqueous solution of the thiourea complex would be preferable for the synthesis of the technetium(III) complex without isolation of the crystals of the thiourea complex. In fact, technetium could be extracted from the aqueous solution of the Tc-thiourea complex with acetylacetone-benzene solution in two steps [38]. More than 95% extraction of technetium was attained using the following procedure [39] First a pertechnetate solution was added to a 0.5 M thiourea solution in 1 M hydrochloric acid. The solution turned red-orange as the Tc(III)-thiourea complex formed. Next, a benzene solution containing a suitable concentration of acetylacetone was added. After the mixture was shaken for a sufficient time (preliminary extraction), the pH of the aqueous phase was adjusted to 4.3 and the aqueous solution was shaken with a freshly prepared acetylacetonebenzene solution (main extraction). The extraction behavior of the technetium complex is shown in Fig. 6. The chemical species extracted into the organic phase seemed to differ from tris(acetylacetonato)technetium(III). Kinetic analysis of the two step extraction mechanism showed that the formation of 4,6-dimethylpyrimidine-... 

Tc2C14(PR3)4] (R3=Et3, PMe2Ph, PMePh2) ch3cn, hbf4 [Tc (CH3CN)10] [BF4]4 The product is an excellent precursor for the synthesis of other low-valent mono-and dinuclear technetium complexes 541... 

Technetium-99, half-life, 127 Tetrahydro-l-phosphanaphthalene complex, synthesis with phosphaalkenes, 30-31 Tetrahydrophosphinanes, synthesis with phosphaalkenes, 21-22... 

Jones AG, Dionauge GF, Davison A et al (1985) Biological distribution and structure function relationship of hexakis isonitrile Tc(I) complexes (abstract). J Nucl Med All Sci 29 200 Jurisson S, Dancey K, McPartlin M, Tasker P, Deutsch E (1984) Synthesis, characterization, and electrochemical properties of technetium complexes containing both tetradentate Schiff base ligands and monodentate tertiary phopshine ligands single crystal structure of trans-(JV,2V-ethy-lene bis(acetylacetone-iminato)bis(triphenylphos- phine)-technetium(III)-hexafluoro-phosphate. Inorg Chem 23 4743-4744... 

Treher EN, Francesconi LG, Gougoutas JZ, Malley M, Nunn A (1989) Mono-capped tris dioxime complexes of technetium (III) synthesis and structural characterization of TCX (dioxime)3, B-R (X=C1, Br dioximedimethylglyoxime cyclohexanedioxime R=CFl3, C4FI9). Inorg Chem 28 3411-3416... 

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