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Reduction of pertechnetate in hot alcoholic solution with 1,2-bis(diphenylphosphino)ethane in the presence of oxalic acid leads to a mixed ligand complex. Characterization of the compound by elemental analysis, IR, UV-Vis, 1H NMR and mass spectrometry indicates that the oxalic acid ligand coordinates as bidentate. A complete crystal and molecular structure determination, performed on one type of crystal of the paramagnetic oxalato-bis(1,2- bis(diphenylphosphino)ethane)technetium(II), is the first structural characterization of a mixed ligand Tc complex with P and O chelate ligand.

Starting from tabulated thermodynamic data of stable compounds in the Mo−O−Cl system, phase diagrams for the Mo−O−Cl system were developed on the basis of GIBBS' phase law by means of thermodynamic calculations. The behaviour of molybdenum trioxide in a temperature gradient tube was investigated experimentally under chlorinating conditions, using99Mo as indicator. The thermochromatografically separated compounds were characterized by their deposition temperature in the temperature gradient tube and by an activation analytical determination of their Mo/Cl ratio. The experimental results were compared with the calculated phase diagram.

Ion mobilities of different99mTc- and99Tc chelates prepared by reduction of pertechnetate by Sn(II) in the presence of citric, malic, tartaric, gluconic, and α-hydroxyisobutyric acid as ligands have been measured by means of electrophoresis without supporting material. All the chelates investigated proved to be anions in the pH range of 2–7. Both the Tc(V)- and Tc(IV) compounds with the same ligand including the99mTc preparation show identical ion mobilities and dissociation characteristics.

The reduction of technetate(VII) by using 1,2 bis(diphenylphosphino)ethane (DPPE) has been investigated as a model for the preparation of new myotropic technetium compounds. Phosphino complexes were isolated and characterized which contain technetium in the oxidation state V ([TcO 2 DPPE 2 ][TcO 4 ]), IV ([TcCl 2 DPPE 2 ][TcCl 6 ]), III ([TcCl 3 DPPE 2 ] 0 ), (TcCl 2 DPPE 2 ]Cl, and II ([TcCl 2 DPPE 2 ] 0 ) dependent on the reaction conditions, in particular Tc/DPPE and Tc/HCl ratios.

99mTc-organocation complexes were screened for heart affinity using the isolated perfused rat heart. The 99mTc-I compounds are better extracted by the heart and retained in it than the 99mTc-III compounds. 99mTcCl2(DMPE)2+ shows low uptake (15%) and fast washout, but no impairment of uptake after incubation with human serum albumin(HSA), with a modified preparation, initial uptake is not much better (18%) but washout is clearly diminished. 99mTc(DMPE)3+ is taken up to a greater extent (33%) if administered solely, but when given in conjunction with HSA, uptake decreases to about 4% because of strong affinity of the complex to the protein, but this compound persists well in the tissue. Detergents like tween 80 and dioctylsulphosuccinate are able to cause higher uptake of 99mTc(DMPE)3+ even in the presence of HSA, thus indicating a diminished binding of the compound to the protein. 99mTc(CN-t-butyl)6+ shows very high uptake (80%) by the heart, which is only moderately diminished by addition of HSA (to 38%), and persists excellently in the myocardium. Basic features of the compounds such as accumulation in and elimination from the myocardium as well as plasma protein binding and their mutual relationships are well reflected by the isolated heart model.

Technetium(V) complexes of the forms TcNL{sub 2} and (TcOL{sub 2})Cl (L = Et{sub 2}tcb{sup {minus}}, morphtcb{sup {minus}}, piptcb{sup {minus}}) with N-(thiocarbamoyl)-benzamidinato (tcb{sup {minus}}) ligands have been synthesized and characterized by elemental analysis and IR, {sup 1}H NMR, and uv/vis spectrocsopy. Selected compounds have been studied by EI and FAB mass spectrometry, including the MIKE technique. A single-crystal x-ray structure determination shows that the cation of bis(N-(N,N-diethylthiocarbamoyl)benzamidinato)oxo-technetium(V) chloride, formula weight 618.5, has a square-pyramidal structure with cis-coordinated ligands. This complex crystallizes in the triclinic space group P{bar 1} with a = 10.87 (2) {angstrom}, b = 11.587 (2) {angstrom}, c = 12.374 (2) {angstrom}, {alpha} = 91.94 (2){degree}, {beta} = 106.04 (2){degree}, {gamma} = 112.18 (2){degree}, and V = 1370.4 (4) {angstrom}{sup 3} with Z = 2 for 4723 independent observed reflections. 50 refs., 4 figs., 4 tabs.

The chemical state of the products of99TcO4− reduction by Sn(II) in citrate media has been investigated using electrochemical methods. The Tc(V) chelates formed after consumption of one mole Sn(II)/g-atom TcO4− were identified as oxo(biscitrato)technetates(V) existing in different coordination isomers. Their reduction products were hydroxo (biscitrato)technetates(IV). The products proved to be the same as reported in the case of the electrochemical reduction of TcO4− in citric acid.

Chemical reactions of 99TcBr62− and different substituted and unsubstituted aliphatic carboxylic acids have been studied using spectrophotometric, electrophoretic, and chromatographic methods. Unsubstituted di- and tricarboxylic acids were unable to stabilize Tc(IV) against hydrolysis in these reactions. In contrast the hydroxycarboxylic acids were able to replace the bromine ligands of the Tc(IV) complex ion resulting in polymeric anionic complex ions and low molecular weight hydroxycarboxylato technetates(IV), even with a monohydroxy-monocarboxylic acid as ligand.

TcO4− is reduced by thiourea /tu/ to Tc/III/ in 6N HCl. By capillar electrophoresis three different cations have been identified with electrophoretic mobilities of u=/4.3−4.8/x10−4 u=/3.2−3.8/x10−4, and u=/2.2−2.8/x10−4 cm2 v−1s−1. These species were assigned to complex cations [Tc/tu/6]3+, [Tc/tu/5Cl]2+, and [Tc/tu/4Cl2]+, respectively. [Tc/tu/6]3+ was identified by spectrophotometry according to recently published data. [Tc/tu/5Cl]2+ was isolated and chemically characterized. The formation of the monovalent cation [Tc/tu/5Cl2]+ was concluded from spectrophotometrical measurements.

The dinitrogen complex (I) is a suitable starting compound for the synthesis of mixed ligand complexes of Tc in its lower oxidation states.

Technetium(V) complexes of the forms TcNL{sub 2} and (TcOL{sub 2})Cl (L = Et{sub 2}tcb{sup {minus}}, morphtcb{sup {minus}}, piptcb{sup {minus}}) with N-(thiocarbamoyl)-benzamidinato (tcb{sup {minus}}) ligands have been synthesized and characterized by elemental analysis and IR, {sup 1}H NMR, and uv/vis spectrocsopy. Selected compounds have been studied by EI and FAB mass spectrometry, including the MIKE technique. A single-crystal x-ray structure determination shows that the cation of bis(N-(N,N-diethylthiocarbamoyl)benzamidinato)oxo-technetium(V) chloride, formula weight 618.5, has a square-pyramidal structure with cis-coordinated ligands. This complex crystallizes in the triclinic space group P{bar 1} with a = 10.87 (2) {angstrom}, b = 11.587 (2) {angstrom}, c = 12.374 (2) {angstrom}, {alpha} = 91.94 (2){degree}, {beta} = 106.04 (2){degree}, {gamma} = 112.18 (2){degree}, and V = 1370.4 (4) {angstrom}{sup 3} with Z = 2 for 4723 independent observed reflections. 50 refs., 4 figs., 4 tabs.