Nitrido-technetium(V) complexes with amino acids: Preparation and X-ray crystal structure of the L-cysteinate ethyl ester technetium(V) complex
- Universita di Ferrara (Italy)
Technetium-99m is the radionuclide of choice in diagnostic nuclear medicine due to its ideal photon energy of 140 keV and half-life of 6 h. Neutral, stable, and lipophilic technetium complexes with diamino dithiol ligands (DADT) have been widely studied as potential brain perfusion agents and a [sup 99m]Tc complex of N,N[prime]-1,2-ethylenediylbis(L-cysteine diethyl ester) (L,L-ECD) has been proposed as a marker of regional cerebral blood flow. It crosses the blood brain barrier (BBB) and is retained in the brain owing to enzymatic hydrolysis of one ester group yielding to a more polar species. More recently, [sup 99m]Tc-cysteine complex has been evaluated in animal distribution studies for tumor diagnosis, but its chemical structure has not been determined. A large number of transition metal complexes with amino acids and peptides have been synthesized and structurally characterized to understand their interactions with proteins and antibodies, as well as biocatalytic processes, but only a limited number of rhenium and technetium compounds have been reported. Up to now, the only technetium complex to be characterized by X-ray analysis that contains amino acids as ligand is [TcO(L,L-ECD)]. The author's interest in the nitrido-technetium chemistry is due to the discovery of a new method for preparing radiopharmaceuticals containing the [[sup 99m]Tc[triple bond]N][sup 2+] core. In this communication the authors report the synthesis and characterization of nitrido-technetium complexes with L-cysteine ethyl ester (CYS-OEt), L-cysteine (CYS) and cysteamine (CSA) and the first X-ray crystal structure of a [TcN][sup 2+]-amino acid complex.
- OSTI ID:
- 5040692
- Journal Information:
- Inorganic Chemistry; (United States), Vol. 32:22; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
TECHNETIUM COMPLEXES
CRYSTAL STRUCTURE
CHEMICAL PREPARATION
ESTERS
TECHNETIUM 99
X-RAY DIFFRACTION
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COHERENT SCATTERING
COMPLEXES
DIFFRACTION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
RADIOISOTOPES
SCATTERING
SYNTHESIS
TECHNETIUM ISOTOPES
TRANSITION ELEMENT COMPLEXES
YEARS LIVING RADIOI
400703* - Radiochemistry & Nuclear Chemistry- Radioisotope Production
550601 - Medicine- Unsealed Radionuclides in Diagnostics