Group 10 Transition-Metal Complexes of an Ambiphilic PSB-Ligand: Investigations into η<sup>3</sup>(<i>BCC</i>)-Triarylborane Coordination
Bibliographic record
Abstract
Reaction of 2,7-di- tert -butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPB) with [PdCl 2 (COD)] resulted in the formation of [PdCl(μ-Cl)(TXPB)] ( 3 ), which can be reduced in a stepwise fashion, forming [Pd(TXPB)] ( 2 ) via [{Pd I (μ-Cl)(TXPB)} 2 ] ( 4 ). Dinuclear 4 could also be prepared through a comproportionation reaction of palladium(II) complex [PdCl(μ-Cl)(TXPB)] ( 3 ) with either [Pd(TXPB)] ( 2 ) or [Pd(dba)(TXPB)] ( 5 ). In complexes 3 and 4, the TXPB ligand is bound to palladium via the phosphine and thioether donors, with a chloride anion bridging between the metal and the borane unit of TXPB. By contrast, the TXPB ligand in 2 is bound to palladium not only via the phosphine and thioether donors but also through a Pd-(η 3 -BAr 3 ) linkage involving boron and the ipso - and ortho -carbon atoms of one B -phenyl ring. The analogous nickel complex, [Ni(TXPB)] ( 6 ) also proved accessible by direct reaction of [Ni(COD) 2 ] with TXPB. In both 2 and 6, short distances (2.02−2.33 Å) between the metal and the B−C ipso −C ortho unit of TXPB and 11 B NMR signals shifted 38−39 ppm to lower frequency of free TXPB confirm the presence of a strong M−{η 3 ( BCC )-BAr 3 } interaction. Reaction of either [Pd 2 (dvds) 3 ] (dvds = 1,3-divinyltetramethyldisiloxane) with TXPB or complex 2 with dvds resulted in rapid formation of [(κ 1 -TXPB)Pd(η 2:η 2 -dvds)] ( 7 ). The platinum analogue of complex 7, [(κ 1 -TXPB)Pt(η 2:η 2 -dvds)] ( 8 ), was also prepared by reaction of [Pt(COD) 2 ] with dvds, followed by TXPB. In both 7 and 8, the metal is trigonal planar as a result of η 2:η 2 -coordination to dvds and bonding only to the phosphine group of TXPB. To assess the potential for a ligand with the same structural characteristics as TXPB to coordinate via three η 1 -interactions, the phosphine analogue of TXPB; 2,7-di- tert -butyl-4,5-bis(diphenylphosphino)-9,9-dimethylthioxanthene (Thioxantphos) was prepared, and reaction with [PtX 2 (COD)] resulted in the clean formation of [PtX(Thioxantphos)]X where X = Cl ( 9 ) and I ( 10 ). These complexes are square planar with the Thioxantphos ligand coordinated through three η 1 -interactions, confirming the steric accessibility of more traditional κ 3 -coordination in 4,5-disubstituted thioxanthene ligands such as Thioxantphos and TXPB.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".