Multisite Magnetization Transfer Studies of Metal Migration in (η<sup>3</sup>-C<sub>7</sub>H<sub>7</sub>)Re(CO)<sub>4</sub>, (η<sup>3</sup>-C<sub>7</sub>H<sub>7</sub>)Os(CO)<sub>3</sub>SnPh<sub>3</sub>, (η<sup>3</sup>-C<sub>7</sub>H<sub>7</sub>)Re(CO)<sub>3</sub>PMe<sub>3</sub>, (η<sup>5</sup>-C<sub>7</sub>H<sub>7</sub>)Re(CO)<sub>3</sub>, (η<sup>5</sup>-C<sub>7</sub>H<sub>7</sub>)Fe(CO)<sub>2</sub>SnPh<sub>3</sub>, (η<sup>5</sup>-C<sub>7</sub>H<sub>7</sub>)Os(CO)<sub>2</sub>SnPh<sub>3</sub>, and (η<sup>5</sup>-C<sub>7</sub>H<sub>7</sub>)Ru(CO)<sub>2</sub>SnPh<sub>3</sub>
Bibliographic record
Abstract
Multisite magnetization transfer (MMT) studies of metal migration around the C 7 H 7 rings in (η 3 -C 7 H 7 )Re(CO) 4 ( 1 ), (η 3 -C 7 H 7 )Os(CO) 3 SnPh 3 ( 2 ), (η 3 -C 7 H 7 )Re(CO) 3 PMe 3 ( 3 ), (η 5 -C 7 H 7 )Re(CO) 3 ( 4 ), (η 5 -C 7 H 7 )Fe(CO) 2 SnPh 3 ( 5 ), (η 5 -C 7 H 7 )Os(CO) 2 SnPh 3 ( 6 ), and (η 5 -C 7 H 7 )Ru(CO) 2 SnPh 3 ( 7 ) are reported. The possible presence of 1,2-, 1,3-, and/or 1,4-metal shifts in the ring fluxionality was investigated in all compounds, and it was shown that both 1,2- and 1,3-shifts occur concurrently in 5 and 6, but that only 1,2-shifts occur in 1, 2, 3, and 4, and only 1,3-shifts in 7 . Several of the compounds exist as mixtures of isomers, and the application of MMT was crucial in unraveling the fluxionality of one isomer in the presence of the other. Thus, MMT experiments allowed the study of the rate of metal migration in the symmetric isomer of 2, which occurs in the presence of more rapid exchange in the asymmetric isomer. The symmetric isomer of 3 was found to exchange faster than the asymmetric isomer. MMT study of the exchange between symmetric and asymmetric isomers of 7 at low temperatures showed that the two enantiomers of the asymmetric isomer exchange directly with the symmetric isomer, but not with each other. MMT experiments allowed the study of metal migration in 7 in the presence of the isomer interchange process. The rate constants and free energies of activation for the metal shifts and for the isomer interchange are reported. It was concluded that orbital symmetry considerations do not provide useful predictions about the mechanisms of metal migration in compounds containing η 1 -, η 3 -, or η 5 -C 7 H 7 rings.
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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 | 0.001 |
| 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".