Bis-hydrocarbyl Platinum(II) Ambiphilic Ligand Complexes: Alkyl–Aryl Exchange between Platinum and Boron
Bibliographic record
Abstract
Reaction of TXPB (2,7-di- tert -butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene) with [PtMe 2 (COD)] (COD = 1,5-cyclooctadiene) yielded [PtMePh(TXPB′)] ( 1; TXPB′ = 2,7-di- tert -butyl-5-methylphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene), presumably via undetected [PtMe 2 (TXPB)]. The ambiphilic ligand in 1 is κ 2 PS -coordinated, and the trigonal plane of the borane is oriented approximately parallel to the square plane at platinum. In solution, 1 is in equilibrium with zwitterionic [PtMe(TXPB-Me)] ( 1 ′), in which the Pt -phenyl group in 1 has been abstracted by the borane; the ratio of 1 to 1 ′ is approximately 90:10 at room temperature and 50:50 at 183 K. The presence of 1 ′ in solution suggests that the pathway for phenyl–methyl exchange between platinum and boron involves a zwitterionic platinum(II) intermediate, rather than a platinum(IV) boryl complex resulting from B–C bond oxidative addition. Heating compound 1 provided an approximate 14:86 mixture of 1 and [PtPh 2 (TXPB″)] ( 2; TXPB″ = 2,7-di- tert -butyl-5-dimethylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene); 1 and 2 are in equilibrium at elevated temperature, and 2 is formed (Δ S ⧧ = −45(12) J K –1 mol –1; Δ H ⧧ = 94(4) kJ mol –1 ) via a second methyl–phenyl exchange between platinum and boron. The solid-state structure of 2 is analogous to that of 1, except with both phenyl groups on platinum and both methyl groups on boron. Compound 1 reacted with PPh 3 or P(OPh) 3 to afford neutral [PtMePh(L)(TXPB′)] {L = PPh 3 ( 3 ) or P(OPh) 3 ( 4 )}, in which the TXPB′ ligand is κ 1 P -coordinated. However, 1 reacted with 2 equiv of CNXyl (Xyl = 2,6-dimethylphenyl) to provide zwitterionic trans -[PtMe(CNXyl) 2 (TXPB-Me)] ( 5; TXPB-Me is a κ 1 P -coordinated anionic phosphine). This divergent reactivity is consistent with the accessibility of both neutral 1 and zwitterionic 1 ′ in solution.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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 teacher head, 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".