Chemistry at High Dilution: Dinuclear ^99 mTc Complexes

Abstract

The formation of di‐ or polynuclear complexes at nanomolar concentrations is generally too slow to be observed with 99mTc. It is reported in this communication that an appropriate choice of potentially bridging ligands, herein thiols HS‐R, accelerates the dimerization reaction to an extent that dinuclear complexes are formed at very high dilution. The dinuclear nature of [99mTc2(μ2‐SR)3(CO)6]− is shown by chromatographic comparison, not only with its rhenium homologue as commonly done, but also with the true 99Tc analogue.

Tricarbonylrhenium(I) and ‐technetium(I) Complexes with Tris(1,2,3‐triazolyl)phosphine Oxides

“…The formation of the [Re 2 (CO) 6 (μ‐X) 3 ] − counter ion in the presence of Ag + ions was unexpected, but underlines the remarkable stability of complexes with anionic ligands bridging two {M(CO) 3 } + units (M=Re, Tc), which has also been found for a number of other examples [42–48] . Even a precedent with mixed Cl − /Br − bridging ligands can be found [49] .…”

“…The formation of the [Re 2 (CO) 6 (μ-X) 3 ] À counter ion in the presence of Ag + ions was unexpected, but underlines the remarkable stability of complexes with anionic ligands bridging two {M(CO) 3 } + units (M = Re, Tc), which has also been found for a number of other examples. [42][43][44][45][46][47][48] Even a precedent with mixed Cl À /Br À bridging ligands can be found. [49] An approximate Br À / Cl À ratio of 1 : 1 was derived for the [Re 2 (CO) 6 (μ-X) 3 ] À counter ions from a disorder refinement of the halides in the obtained single crystals.…”

The “Carbonyl Story” and Beyond; Experiences, Lessons and Implications

“…Within the same context, we showed for the first time that dinuclear 99m Tc 2 complexes do exist. If mechanisms and rates match, multinuclear 99m Tc complexes might exist and also account for unidentified side‐products in common syntheses (Scheme ) …”

“… Preparation of mixed 99m Tc/Re cluster by self‐assembly (a) and dinuclear 99m Tc 2 complex from highly diluted solutions …”

Single crystal growth of water-soluble metal complexes with the help of the nano-crystallization method

“…The first coordination complex crystallized by this technique has just been reported. 8 With coordination metal complex cations, the counteranion has an influence upon various structural aspects such as dimensionality, topology and nuclearity, and other parameters dependent on the structure, such as the magnetic behavior of cobalt(II), 9 copper(II), 10 zinc(II), 11 silver(I), 12 cadmium(II), 13 mercury(II) 14 and dysprosium(III) 15 coordination complexes. It is a common feature of these studies that they are limited to simple anions, whose metal salts are already commercially available and which serve as starting materials for the complex formation.…”