Technetium: Organometallic ChemistryBased in part on the article Technetium: Organometallic Chemistry by Ronald J. Clark which appeared in the <i>Encyclopedia of Inorganic Chemistry, First Edition</i> .
Bibliographic record
Abstract
Abstract The chemistry of organometallic technetium compounds is discussed along with its application in the field of nuclear medicine. Several 99m Tc radiopharmaceuticals are presently used in hospitals using a 99 Mo− 99m Tc generator to prepare the starting material [ 99m TcO 4 ] − . The isotope 99m Tc is a γ‐ray emitter. The most common organometallic radiopharmaceutical is [Tc(MIBI) 6 ] + , where MIBI is an isonitrile ligand. 99m Tc can be produced only at the tracer level and it disintegrates to the longer life isotope 99 Tc, which has a half‐life of 2.12 × 10 5 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 (H 2 O) 3 ] + is particularly important, since a kit was recently developed for its preparation. It should open a new field for the development of 99m Tc 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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.076 | 0.062 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".