Room-Temperature Synthesis of Re(I) and Tc(I) Metallocarboranes
Bibliographic record
Abstract
A series of carborane derivatives bearing guanidine substituents were prepared and characterized, and their reactivity toward Re(I) and Tc(I) in aqueous media was evaluated. Guanidinylation was achieved by treating 1-aminomethyl-1,2- closo -dodecaborane with N 1, N 2 -di-Boc-1 H -pyrazole-1-carboxamidine, and the associated N -ethyl derivative, which produced the desired products in good (circa 50%) yield. These were deprotected and converted to the corresponding nido -carboranes, which, when combined with [M(CO) 3 (H 2 O) 3 ] + (M = Re and 99m Tc) at room temperature for 3 h or 35 °C for 1 h, afforded the corresponding η 5 -metallocarborane complexes. Corresponding reactions involving carboranes without basic substituents generally require microwave heating at temperatures greater than 150 °C. The rate, yields, and the temperature of the reaction appear to be dependent on the basicity of the guanidines tested. The biodistribution of two of the 99m Tc complexes, which are stable indefinitely in solution, were evaluated in vivo in CD1 mice and showed that the 99m Tc–carboranyl guanidine complexes clear key nontarget organs and tissues within one half-life (6 h) and have properties that are desirable for developing targeted molecular imaging probes.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".