Synthesis, structural characterization, and reactivity of (thiolato)bismuth complexes as potential water-tolerant Lewis acid catalysts
Bibliographic record
Abstract
We have synthesized bismuth complexes incorporating polydentate mono- and di-thiolate ligands and examined their utility as water-tolerant Lewis acid catalysts. The reaction of Bi(OAc)3 or Bi(NO3)3·5H2O and the corresponding mono- or di-thiol(ate) yielded the compounds [(SNNS)Bi(OAc)] (4), [(SNNSPr)Bi(OAc)] (5), [(NNS2)Bi(OAc)] (6), [(ONS2)Bi(OAc)] (7), [(ONS2)Bi(NO3)] (8), and [(NNS)2Bi][NO3] (9) [H2(SNNS) = N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)ethylenediamine; H2(SNNSPr) = N,N′-diethyl-N,N′-bis(2-mercaptoethyl)propanediamine; H2(NNS2) = N,N-diethyl-N′,N′-bis(2-mercaptoethyl)ethanediamine; H2(ONS2) = 2-methoxyethyl-bis(2-mercaptoethyl)amine; H(NNS) = N,N-diethyl-N′-(2-mercaptoethyl)ethanediamine]. The solid-state structures of 4–8 show similar distorted pentagonal pyramidal geometries at the bismuth centre with a thiolate sulfur atom in the axial site, whereas 8 shows second structural arrangement with a distorted trigonal bipyramidal geometry at bismuth. The cation of 9 shows two NNS-bonded ligands and a distorted octahedral geometry at bismuth. Two-dimensional NMR studies of 4–8 show geminal 1H coupling in –SCH2CH2N– groups and suggests strong dative Bi–N intramolecular interactions. Bi(NO3)3·5H2O and BiCl3 show high activity toward the esterification of stearic acid, Bi(NO3)3·5H2O, and 4–7 and 9 show high activity toward the transesterification of methyl stearate in butanol, and 7 shows moderate activity as a catalyst for the transesterification of glyceryl trioctanoate in methanol.
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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 | 0.000 |
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".