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Technetium and rhenium: coordination chemistry and nuclear medical applications

“…These aspects have recently led to the development of different approaches based on nitridotechnetium complexes or organometallic compounds. To the latter group belong tricarbonylrhenium(I) and -technetium 31 It is remarkable that essentially all kind of donor atoms can be used since the stability of the complexes is purely kinetic. 32 Mono-, bi-and -tridentate ligands are only cleaved under drastic conditions such as high temperatures or strongly acidic solutions.…”

Potential of the "[M(CO)3]+" (M = Re, Tc) Moiety for the Labeling of Biomolecules

“…Systematic study of the chemical factors which influence binding of the SCN-Bzl-DTPA to protein has been reported earlier [13], A pivotal issue in designing an optimal radiotherapeutic reagent is the chemical stability of the metal chelate system. The complexes of Bi +3 ions with eight-coordinated DTPA are kinetically inert in aqueous solutions with the overall equilibrium constant of 4X10 35 Μ 1 (at 20° C and 0.1 Μ ionic strength, [17]). The in vivo stability of 212 Bi-CHX-DTPA antibody (anti-Tac) has also been demonstrated earlier [5] and the in vivo stability of 213 Bi labeled 34A and 201B antibodies has been reported by us in these proceedings [6],…”

“…Subsequently, the organic solvent was evaporated and then replaced by a buffer medium of choice. As described elsewhere [17] the three [X]~ are readily substituted by water (or other solvent) molecules, thus, the "semi aqua-ion" [M(OH 2 ) 3 Tc by introduction of thiol groups with a derivatiz- ing reagent such as iminothiolane or by reduction of the disulfide bridges has recently been described. It could be shown that incorporation takes place but is slow [18][19][20].…”

“…The yield and enrichment factor were measured for the Szilard-Chalmers effect on neutron irradiated targets to investigate the feasibility of this method of production of high specific activity 186 Re. The basis of this process lies in the assumption that lower oxidation states of rhenium will tend to react with oxygen to form water-soluble Re(VII) when provided with sufficient activation energy from the recoil process (which yields transient temperatures of many thousands of degrees Kelvin Re have been relatively low (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), they have been reproducible. Of greater significance is the observation that scaling up from 5 second irradiations at 4 Χ 10 13 thermal neutrons cm 2 /s to 30 minute irradiations at the same flux did not significantly reduce the enhancement factor, indicating that the low enrichment factors were probably due to the poor target preparation instead of radioactive decomposition.…”

Synthesis of Oxorhenium(V) Complexes Derived from 7α-Functionalized Testosterone: First Rhenium-Containing Testosterone Derivatives

“…The complex formation according to the "3ϩ1" concept by the use of two different rhenium precursors 9 [12] and 10 [15] offers the access to oxorhenium(V) complexes which differ in the central donor atom of the tridentate ligand part, being S for 12 and O for 13. The corresponding mixed-ligand complexes 12 and 13 could be obtained as reddish-brown and wine-red amorphous glasses in 71% (for 12) and 14% (for 13) yield, respectively (Scheme 2).…”