| Abstract
| - Chemical or electrochemical reduction of the 1,4,7-trithiacyclononane (9S3) complexes [MII(9S3)2][BF4]2 (M =Re (3a) or Tc (3b)) results in instantaneous C−S bond cleavage to yield ethene and the stable MIII thiolatecomplexes [MIII(9S3)L][BF4] (M = Re (4a) or Tc (4b), L = SCH2CH2SCH2CH2S). Compounds 4 have beencharacterized by 1H NMR spectroscopy, and the pseudo-octahedral geometry of 4b has been confirmed by X-raycrystallography. Upon electrochemical reduction 4a loses ethene, while 4b can be reversibly reduced to [TcII(9S3)L], which is then further reduced to Tc(I) with loss of ethene. Successive ethene loss is observed in themass spectra of compounds 3 and 4. The radiosynthesis of 4a with 188Re can be comfortably completed within10 min starting with 188ReO4- from a 188W/188Re generator, with a radiochemical yield in excess of 90%, andthus represents a practical approach to the preparation of stable 188Re (and 99mTc) thioether complex derivatives/conjugates for clinical use. Crystal data: 4b, C10H20S6Tc, orthorhombic Pbca, a = 12.233(2) Å, b = 14.341(2)Å, c = 20.726(3) Å, Z = 8.
- Chemical or electrochemical reduction of the 1,4,7-trithiacyclononane (9S3) complexes [M(9S3)2][BF4]2 (M = Re (3a) or Tc (3b)) results in instantaneous C−S bond cleavage to yield ethene and the stable MIII thiolate complexes [M(9S3)L][BF4] (M = Re (4a) or Tc (4b), L = SCH2CH2SCH2CH2S). The radiosynthesis of 4a with 188Re can be comfortably completed within 10 min starting with 188ReO4- from a 188W/188Re generator, with a radiochemical yield in excess of 90%, and thus represents a practical approach to the preparation of stable 188Re (and 99mTc) thioether complex derivatives/conjugates for clinical use.
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