Technetium: Organometallic Chemistry
Published Online: 15 MAR 2006
Copyright © 2006 John Wiley & Sons, Ltd
Encyclopedia of Inorganic Chemistry
How to Cite
Rochon, F. D. 2006. Technetium: Organometallic Chemistry . Encyclopedia of Inorganic Chemistry. .
- Published Online: 15 MAR 2006
The chemistry of organometallic technetium compounds is discussed along with its application in the field of nuclear medicine. Several 99mTc radiopharmaceuticals are presently used in hospitals using a 99Mo− 99mTc generator to prepare the starting material [99mTcO4]−. The isotope 99mTc is a γ-ray emitter. The most common organometallic radiopharmaceutical is [Tc(MIBI)6]+, where MIBI is an isonitrile ligand. 99mTc can be produced only at the tracer level and it disintegrates to the longer life isotope 99Tc, which has a half-life of 2.12 × 105 years. The chemistry of technetium has been studied with the latter isotope, which is commercially available. But it emits weak β− particles and special precautions must be taken in the laboratories in order to avoid health problems.
Most of the publications in the literature on organometallic Tc compounds contain the ligands CO, isonitriles or the cyclopentadienyl ion. These π-accepting ligands usually bind to Tc in a low oxidation states. Tc-CO compounds are the ones who have been most studied. Binary compounds and a great variety of mixed-ligands complexes are discussed. The new complex ion [Tc(CO)3(H2O)3]+ is particularly important, since a kit was recently developed for its preparation. It should open a new field for the development of 99mTc radiopharmaceuticals. It can bind to biomolecules like proteins, peptides, and antibodies which have very specific targets.
Several Tc-cyclopentadienyl complexes have the sandwich or the piano stool structures. The arene compounds should have similar structures, but the latters have not been much studied yet. No Tc-arene compound seem to have been characterized by crystallographic methods yet. But more recently, interest in the arene complexes has increased because of its potential use in nuclear medicine. Isonitriles or isocyanides and cyanide ligands are bonded to Tc through the C atom. A few crystal structures on mixed-ligand isonitrile Tc complexes were determined and the segment TcCNC is linear. Fewer cyanide Tc compounds were studied. Finally a few Tc-alkyl compounds have been reported.
- carbon monoxide;