Thermochemistry of cis trans isomerization in MCl<sub>2</sub>L<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub>, M=Ru, Os; L=CO, CNCH<sub>2</sub>SO<sub>2</sub>‐<i>p‐</i>tolyl.
Bibliographic record
Abstract
Abstract Ten neutral dichlorobistriphenylphosphine complexes of ruthenium(II) and osmium(II) with two π‐accepting ligands, CO or CNCH2SO2‐p‐tolyl (TosMIC), have been prepared and characterized. There are five pairs of complexes, each with trans‐triphenylphosphines and either cis or trans arrangement of the two chlorides and two π‐accepting ligands. The all‐trans arrangement, ttt‐MCl2L2(PPh3)2 are prepared under kinetic control by adding 2 L to MCl2(PPh3)3. In most cases these can be stoichiometrically thermally isomerized to the more thermodynamically stable cct‐MCl2L2(PPh3)2 as either a solid or in solution with high boiling solvent. Mixed carbonyl/isocyanide complexes form by treating ttt‐MCl2(CO)2(PPh3)2 with excess isocyanide at room temperature to give ttt‐MCl2(CO)(CNR)(PPh3)2 with retention of stereochemistry at the metal. Thermolysis of these mixed species also cleanly transform to the thermodynamically stable cct‐isomers. Differential scanning calorimetry is used to determine the temperature onset (155–229 °C) and enthalpy (19–92 J/mol) for these isomerizations. In examples with at least one CO ligand, these DSC methods allow for Borchardt‐Daniels kinetics determination of the energy of activations for these isomerizations between 169–282 kJ/mol. Single crystal X‐ray diffraction confirms the spectroscopically assigned geometries and DFT calculations of the most likely intermediates for carbonyl substitution in ttt‐MCl2(CO)2(PPh3)2 supports carbonyl loss as the initial step in these substitution reactions. It is proposed that isomerization competes with geminate recombination of the dissociated CO or CNR to give the starting isomer ttt‐MCl2L2(PPh3)2.
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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) | 0.003 | 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".