Cationic Sulfonium-based Tripodal Ligand and its Rh(I) Complexes
Bibliographic record
Abstract
ABSTRACT Herein we report the first cationic tripodal ligand—consisting of a sulfonium donor embedded in a tripodal scaffold—together with its mono‐ and bis‐ cationic Rh(I) complexes. To elucidate the distinctive properties of this new ligand, its Rh(I) carbonyl complex was subjected to comprehensive structural (XRD) and spectroscopic (NMR, IR) analyses, compared to the isostructural analogs with neutral P‐based and anionic Si‐based ligands. This comparative study revealed systematic trends along the series, including a progressive shortening of the E‐Rh bond (E = Si, P, S) and increasing blue shifts of the CO stretching frequencies. These observations were corroborated by DFT calculations, which also indicated a steady negative charge depletion on Rh along the series. Electrochemical studies (CV) further highlighted the effect of the cationic sulfonium donor, revealing an anodic shift of ∼1.4 V in the Rh(I) reduction potential, relative to the P‐based analog. Lewis acidity measurements of the coordinatively unsaturated Rh(I) complexes (by the Guttman‐Becket method) yielded acceptor numbers approaching those of polyfluoroaryl boranes for the sulfonium complex. Finally, by representative 2:1 condensations of N‐methylindole with carbonyl compounds, we demonstrated how the high Lewis acidity of the Rh(I) center, imparted by its sulfonium coordination, can be exploited in Lewis acid catalysis.
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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) | 0.001 | 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".