Synthèse et caractérisation de complexes de technétium(V) et de rhénium(V) contenant des acides aminés et des dipeptides
Bibliographic record
Abstract
Equivalent amounts of ReOX3(OPPh3)(Me2S) (where X = Cl, Br) and L-histidine (L-hisH) in acetonitrile yield ReOX2(L-his), in which the amino acid monoanion is N,N,O-tridentate.X-ray diffraction work on both compounds shows that the three donors occupy a face in a distorted octahedron and the carboxylate oxygen is coordinated trans to the Re=O bond.The 2:1 complex [ReO(L-his)2]I is obtained by reacting 2 equiv of L-histidine with Re021(PPh3)2 in methanol in the presence of NaOCH3.'H NIVIR spectroscopy indicates that these complexes contain one N,N,O-tridentate histidine anion coordinated as above and one N,N-bidentate histidine anion, whose carboxylate group is free.By refluxing ReOX2(L-his) in methanol, the carboxylic groups esterify and two octahedral units condense into an oxo-bridged dinuclear complex {ReOX2(L-hisMe)}20 containing N,N-bidentate histidine methyl ester.The O=Re-O-Re=O backbone is approximately linear and the two ReOX2(L-hisMe) units are related by a twofold axis through the central oxygen.Crystals of {ReOBr2(L-hisMe)}20 consist of an ordered phase containing two of the possible diastereoisomers in a 1:1 ratio.'H NIvIR spectra of these crystais include two sets of signais, consistent with the presence of two isomers with C2 symmetry, and the spectra of the non-recrystaliized materiai confirm that these are the only two isomers formed.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".