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Your search keyword '"Bernhardt, Paul V."' showing total 36 results
Start Over Author "Bernhardt, Paul V." Publisher csiro publishing
36 results on '"Bernhardt, Paul V."'

8. Synthesis and Characterisation of Indium(iii) Bis-Thiosemicarbazone Complexes: 18F Incorporation for PET Imaging.

Author

Venkatachalam, Taracad K., Bernhardt, Paul V., Pierens, Gregory K., Stimson, Damion H. R., Bhalla, Rajiv, and Reutens, David C.

Subjects
*METHANOL, *LIGANDS (Chemistry), *HALIDES
Abstract

Several structurally related indium chlorido complexes of bis-thiosemicarbazones were prepared, starting from the appropriately substituted bis-thiosemicarbazones, using sodium methoxide in methanol. Detailed NMR studies were conducted to assign the structure including COSY, HSQC, and HMBC techniques. The structures of all indium complexes were solved using single crystal X-ray diffraction. The chlorido ligand was present at the apex of the square pyramidal coordination sphere in all indium complexes. In some complexes, an intermolecular hydrogen bond was present between the chlorine atom and an NH group. Three different indium chlorido complexes were converted into the corresponding fluorido-derivative by a simple halide exchange method using K18F. These novel complexes, containing the positron emitting isotope 18F, may have potential applications in positron emission tomography (PET). Three different indium chlorido complexes were converted into the corresponding fluorido derivative by a simple halide exchange method using K18F. These novel complexes, containing the positron emitting isotope 18F, may have potential applications in positron emission tomography (PET). [ABSTRACT FROM AUTHOR]

Published
2019
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10. A Novel Strategy to Introduce 18F, a Positron Emitting Radionuclide, into a Gallium Nitrate Complex: Synthesis, NMR, X-Ray Crystal Structure, and Preliminary Studies on Radiolabelling with 18F.

Author

Venkatachalam, Taracad K., Bernhardt, Paul V., Stimson, Damion H. R., Pierens, Gregory K., Bhalla, Rajiv, and Reutens, David C.

Subjects
*RADIOISOTOPES, *SODIUM, *PENTANE
Abstract

A hexan-3,4-dione bis(4N-phenylthiosemicarbazone) gallium nitrate complex was synthesised and the structure was confirmed by NMR studies. The complex was prepared using an appropriately substituted dithiosemicarbazone and sodium methoxide in anhydrous methanol. The structure was further confirmed using single crystal X-ray crystallography. The crystal structure of gallium nitrate complex of diphenylthiosemicarbazone comprise a planar configuration of the tetradentate coordinated thiosemicarbazone with the Ga3+ ion, with the nitrate ligand occupying the apical coordination site. The X-ray structure of the gallium fluoride complex of pentan-2,3-dione bis(4N-phenylthiosemicarbazone) has been determined and confirms exchange of the nitrate can be achieved with fluoride. We show facile exchange of 18F, a positron emitter, to form the 18F-gallium complex under mild conditions, thus providing confirmation that such a transformation can be used to introduce 18F directly into nitrate-coordinated complexes of gallium-thiosemicarbozone complexes, a new labelling strategy for the preparation of imaging agents. [ABSTRACT FROM AUTHOR]

Published
2018
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13. Heteronuclear NMR Spectroscopic Investigations of Gallium Complexes of Substituted Thiosemicarbazones Including X-Ray Crystal Structure, a New Halogen Exchange Strategy, and 18F Radiolabelling.

Author

Venkatachalam, T. K., Pierens, G. K., Bernhardt, Paul. V., Stimson, D. H. R., Bhalla, R., Lambert, L., and Reutens, D. C.

Abstract

Five thiosemicarbazone ligands have been synthesized, and their coordination chemistry with gallium was investigated. The reaction of these thiosemicarbazones with gallium chloride in alcohol solutions in the presence of a base yielded the corresponding penta-coordinated Ga-Cl metal complexes. In contrast, the reaction of gallium nitrate with the ligands in the presence of alkoxides resulted in the formation of the corresponding Ga-alkoxides, rather than the anticipated Ga-nitrate complex. The crystal structures of gallium chloride and gallium methoxide complexes of diphenylthiosemicarbazone comprise a planar configuration of the tetradentate-coordinated thiosemicarbazone with Ga3+ ion, with the chloride or methoxide groups occupying the apical coordination site. The corresponding ethoxido complex was also prepared in an identical fashion, and NMR analysis confirmed structural similarity to the methoxido complex. Facile halogen exchange reactions of the gallium chloride complexes were achieved by treatment with silver nitrate, followed by addition of KF or KI to generate the gallium fluoride and iodide complexes, respectively. This method of exchange using halogenated inorganic salts aids the preparation of group 13 fluorides, which are notoriously insoluble in organic solvents, for complexation with organic ligands. All compounds have been fully characterized by NMR, and the X-ray crystal structures of two of the complexes are reported. Additionally, the positron-emitting isotope 18F was introduced in the structure of the diphenyl gallium thiosemicarbazone complex. [ABSTRACT FROM AUTHOR]

Published
2016
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