Publisher Summary Over the past two decades there has been a phenomenal increase in the study of the chemistry of transition metal complexes containing sulfur ligands. There are a number of reasons for this, the major one being the revitalization of the chemistry of the unsaturated sulphur donor chelates. These were used as early as the 1930s as analytical reagents for various metals. The interest in complexes of these ligand systems now embraces areas ranging from purely academic syntheses to large-scale industrial production. Almost every available physical technique has been utilized for the elucidation of the molecular and electronic structures and the kinetics manifested in these systems. The spiraling interest in the complexes of sulfur donor ligands has prompted number of excellent and frequently exhaustive reviews. Other reasons for the expansion of the field of dithiochelate chemistry have undoubtedly included the correlations of model complexes with biological systems.

1,2-Dithiolene Complexes of Transition Metals

Technetium Chemistry and Technetium Radiopharmaceuticals

Chemical and thermodynamic data for Technetium (Tc) and some of its inorganic compounds and aqueous species are reviewed here. Major emphasis is given to systems with potential geochemical applications, especially the geochemistry of radioactive waste disposal. Compounds considered include oxides, hydroxides, hydrates oxides, halides, oxyhalides, double halides, and sulfides. The aqueous species considered include those in both noncomplexing media (pertechnetates, technetates, aquo-ions, and hydrolyzed cations) and complexing media (halides, sulfates, and phosphates). Thermodynamic values are recommended for specific compounds and aqueous ions when reliable experimental data are available. Where thermodynamic data are inadequate or unavailable, the chemistry is still discussed to provide information about what needs to be measured, and which chemistry needs to be clarified. A major application of these thermodynamic data will be for chemical equilibrium modeling and for construction of potential-pH diagrams for aqueous solutions. Unfortunately, the present lack of data precludes such calculations for complexing aqueous media. The situation is much better for noncomplexing aqueous media, but the chemistry and thermodynamics of cationic Tc(V) species and hydrolyzed Tc(III) species are poorly understood. 240 references, 6 tables.

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Critical review of the chemistry and thermodynamics of technetium and some of its inorganic compounds and aqueous species

Structural and DFT/TD-DFT investigation of tris(bidentate) complexes of rhenium(III) synthesized from the cis-[ReO2]+ core and benzenethiol derivatives

Publisher Summary This chapter describes the coordination chemistry of technetium focusing on technetium(−I), technetium(0), technetium(I), technetium(II), technetium(III), technetium(IV), technetium(V), technetium(VI), and technetium(VII). Technetium(III) complexes with aminocarboxylato ligands have been observed but none are well characterized. 99m Tc–iminodiacetate complexes formed with 2,6-alkylphenyl [ArNHCOCH 2 N(CH 2 COO) 2 ] 2− ligands are used to image the hepatobiliary system. One of the approaches to cationic myocardial imaging agents has been the development of neutral seven-coordinate Tc(III) complexes based on 1,2-dioxime ligands (dioximeH 2 ) with one end capped by a boronic acid derivative. These complexes are generally referred to as boronic acid adducts of technetium dioximes (BATOs). The highest binary chloride of technetium is the dark red TcCl 4 formed as the major product of the chlorination of Tc metal. Crystallography reveals a polymeric chain structure of C1-bridged distorted octahedral TcCl 6 units. The structure and chemistry of the square-pyramidal five-coordinate and pseudo-octahedral six-coordinate [Tc V O] 3+ complexes are dominated by the strong tetragonal distortion induced by the multiply bonded oxo ligand.

Munetsugu Kawashima

Papers

Electron transfer reactions and the nature of the solvent effect on tris-toluene-3,4-dithiolates of rhenium, tungsten, molybdenum and technetium

Aquation of hexahalogenotechnetium(IV)