Probing substituent effects on the activation of H2 by phosphorus and boron frustrated Lewis pairs
Bibliographic record
Abstract
The impact of substituent changes on phosphorus and boron-containing frustrated Lewis pairs (FLPs) has been examined. The phosphites (RO)(3)P R = Me, Ph form classical Lewis acid-base adducts of the formula (RO)(3)PB(C(6)F(5))(3) R = Me ; R = Ph , whereas P(O-2,4-(t)Bu(2)C(6)H(3))(3) and P(O-2,6-Me(2)C(6)H(3))(3) generate FLPs. Nonetheless, these latter combinations do not react with H(2). The more basic phosphinite tBu(2)POR, R = tBu reacts with B(C(6)F(5))(3) to give (tBu(2)(H)PO)B(C(6)F(5))(3). The related species tBu(2)POR, R = Ph ; 2,6-Me(2)C(6)H(3) showed no reaction with B(C(6)F(5))(3) but the FLPs react under H(2) (4 atm) to give [tBu(2)P(OR)H][HB(C(6)F(5))(3)] R = Ph and 2,6-Me(2)C(6)H(3). Similarly, tBu(2)PCl in combination with B(C(6)F(5))(3), generates an FLP that upon addition of H(2), gives [tBu(2)PH(2)][ClB(C(6)F(5))(3)] albeit in low yield. The diborane 1,4-(C(6)F(5))(2)B(C(6)F(4))B(C(6)F(5))(2) in combination with either tBu(3)P or (C(6)H(2)Me(3))(3)P generates FLPs that react with H(2) to give [R(3)PH](2)[1,4-(C(6)F(5))(2)HB(C(6)F(4))BH(C(6)F(5))(2)] (R = tBu , C(6)H(2)Me(3)). Similarly PhB(C(6)F(5))(2) and tBu(3)P react with H(2) giving [tBu(3)PH][HBPh(C(6)F(5))(2)] . The combination of B(OC(6)F(5))(3) and PtBu(3) also generate an FLP which reacts with H(2) to give [HPtBu(3)][B(OC(6)F(5))(4)] , the product of substituent redistribution. The boronic esters, (C(6)H(4)O(2))BC(6)F(5), (C(6)H(3)FO(2))BC(6)F(5) and (C(6)F(4)O(2))BC(6)F(5), and the borate esters B(OC(6)H(3)(CF(3))(2))(3), B(OC(6)H(2)F(3))(3) and B(OC(6)H(4)CF(3))(3) were prepared and shown to generate FLPs with tBu(3)P or (C(6)H(2)Me(3))(3)P. Nonetheless, no reaction with H(2) was observed for . Collectively these data suggest that there is a threshold of combined Lewis acidity and basicity that is required to effect the splitting of H(2).
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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) | 0.000 | 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 | 0.001 |
| 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 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".