Search

The preparation and crystal structures of two modifications of Hg2MoO4 are reported. At high temperature Hg2MoO4 (the beta-modification) crystallizes with a structure, where MoO4 tetrahedra are linked through Hg2 dumb-bells, thus forming infinite zig-zag chains and at low temperature Hg2MoO4 (the alpha-modification) contains MoO6 octahedra, which are linked via common edges to form zigzag chains, which are further linked via Hg2 dumb-bells, thus forming puckered two-dimensionally infinite sheets.

The preparation of a new series of mixed-ligand oxorhenium complexes with ligands containing the SNN donor set (general formula RCH(sub 2)(CH(sub 2)NHCH(sub 2)CH(sub 2)SH, where R = N(N2H5)(sub 2), pyrrolidin-1-yl, or N[CH(CH3)](sub 2)) and monodentate thiols as coligands is presented. When R = N[CH(CH3)](sub 2), the tertiary nitrogen of the ligand does not participate in the coordination sphere of the metal, a novel type of '2+1+1' [SN][S][S] complex was obtained and X-ray and NMR assignments were performed for these mixed-ligand complexes.

Syn- and anti-oxorhenium complexes of ReO[(C2H5)2NCH2CH2N(CH2CH2S)2] [SC6H4OCH3] were synthesized by the reaction of ReO3+ with (C5H5)2NCH2CH2N(CH2Ch2SH)2 and HSC6H4OCH3. The syn-oxorhenium complex exhibits a distorted trigonal bipyramidal geometry around its rhenium atom with a basal plane that is composed of the sulfur atoms of the tridentate ligand and the oxo group. On the other hand, the rhenium atom of the anti-oxorhenium complex exhibits a distorted square pyramidal geometry with basal plane that is composed of SNS donors.

The reaction of Tc(V)-gluconate with ligands L1H2 having SNN donor set and L2H, (thiols) yields four neutral '3+1' mixed ligand oxotechnetium complexes, TcO(R1CH2CH2NCH2C(R2)sub2S)-(SR) where RSH = p-methoxybenzenethiol, p-methylbenzenethiol, or benzyl mercaptan. The complexes have a square pyramidal geometry with oxo ligand at axial position. The tridentate L1H2 ligand chelates and one position cis to the oxo group is occupied by a coligand like thiol. X-ray crystallography, 1H- and 13C-NMR give the elemental and spectroscopic characterization.

The preparation and characterization of 22 mixed-ligand complexes of the general formula TcOL1L, where LiH2 = N-substituted bis(2-mercaptoethyl)amine ligands, SN(R)S; L2H = monodentate thiols as coligand, are described. The compounds were prepared by the ligand exchange technique using Tc-gluconate as precursor and equimolar amounts of the two ligands. X-ray crystal analysis showed trigonal bipyramidal geometry for syn isomers and distorted square bipyramidal for the anti isomers.

A novel method of synthesizing a series of oxotechnetium(V)-99 complexes with aza-substituted 2,6-dimethyl-4-azaheptane-2,6-dithiol ligands and benzyl mercaptan as coligand proceeds through a reaction between 99Tc(V) gluconate, and benzyl mercaptan and tris-chealating ligand in a 1:1 ratio. These complexes crystallize in monoclinic system and the side chain of the end product has a syn configuration, as revealed by spectroscopic and elemental analyses.

The synthesis, radiochemistry and biodistribution in mice of 99mTcO{[(CH3CH2)2NCH2CH2-N(CH2CH2S)2] ( p-SPh-COOCH2CH3)}, I, are reported herein. Complex I forms by binding of (CH3CH2)2NCH2CH2N(CH2CH2SH)2 and p-HSPhCOOCH2CH3 ligands to reduced 99mTc using glucoheptonate (GH) as transfer ligand. Corroboration of structure with an authentic 99gTc sample is achieved by reverse phase high pressure liquid chromatography (RP-HPLC) adopting parallel radiometric and photometric detection modes. By incubation at 37°C with glutathione (GSH) in aqueous medium I tranforms to an hydrophilic compound, as shown by HPLC. Tissue distribution experiments reveal high uptake and retention of I in mice brain. [ABSTRACT FROM AUTHOR]

Ethyl cysteinate dimer (ECD) labelled with reduced technetium-99m has recently been proposed as a promising radiopharmaceutical for brain perfusion imaging. In the present study a single-component kit formulation has been developed, thus simplifying the radiolabelling procedure. A method of analysis by electrophoresis has also been developed, permitting identification of radiochemical impurities in the preparation. Tc-ECD prepared by the single-component kit was further evaluated in primates and humans. The results demonstrated that the complex is stable in vivo, rapidly extracted and retained in the brain tissue for a sufficient time for single-photon emission tomography studies. Therefore the present single-component kit formulation can be proposed as a reliable instant freeze-dried kit for routine preparation of 99-Tc-ECD required for scintigraphic assessment of regional cerebral blood flow. [ABSTRACT FROM AUTHOR]

The in vivo kinetics of five new Tc-labelled acetanilido iminodiacetates, analogous to Tc-p-butyl IDA, were studied in experimental animals by means of their distribution in mice and scintigrams of rabbits. The new compounds were specifically eliminated via the hepatobiliary system with various rates of hepatic extraction. Urinary excretion of the complexes was minimal. [ABSTRACT FROM AUTHOR]

The absorbed dose estimates of several organs after administration in humans of six new hepatobiliary agents (five Tc-Pyridoxal amino acid complexes and the Tc-HIDA) are presented in comparison with I-Rose-Bengal. The results indicated that the radiation doses absorbed by the total body and gonads as well as by the critical organ (upper part of the large intestine) are significantly lower than those of Rose Bengal. Therefore, the new Tc-agents can be safely applied to humans. [ABSTRACT FROM AUTHOR]