Enhancing Electron Accepting Ability of Triarylboron via π-Conjugation with 2,2‘-Bipy and Metal Chelation: 5,5‘-Bis(BMes<sub>2</sub>)-2,2‘-bipy and Its Metal Complexes
Bibliographic record
Abstract
The synthesis of a new diboron compound, 5,5‘-bis(BMes 2 )-2,2‘-bipy (B2bipy, 1 ), has been accomplished. The conjugation of the 2,2‘-bipy unit with the two BMes 2 groups in 1 has been found to greatly enhance the electron-accepting ability of the boron centers, compared to the biphenyl analogue. 1 is an effective chelate ligand for metal ions and three metal complexes; namely, [Cu I (B2bipy)(PPh 3 ) 2 ][BF 4 ], 2, Pt II (B2bipy)Ph 2, 3a, and Pt II (B2bipy)Me 2, 3b, have been synthesized. The binding of metal ions to B2bipy was found to further significantly increase the electron-accepting ability/Lewis acidity of the boron centers. Cyclic voltammetry diagrams revealed that the free ligand and all three complexes display two reversible reduction peaks that are separated by 0.31−0.40 V. The first reduction potential ( E 1/2 ) for 1, 2, 3a, and 3b was found to be −1.69, −1.36, −1.34, and −1.38 V, respectively, versus FeCp 2 +/0 in DMF, which supports that the electron-accepting ability of the metal complexes is much greater than that of BMes(C 6 F 5 ) 2 . The strong electron-accepting ability/Lewis acidity of the metal complexes and the free ligand was manifested by their ability to sequentially bind to 2 equiv of F - ions in non-alcoholic solvents with K 1 ≥ 10 8 and 10 9 M -1 for 1 and 3a, respectively, and to 1 equiv of F - ions in the presence of methanol/ethanol or water. The crystal structures of 1, its 2:1 fluoride adduct [NBu 4 ] 2 [ 1F 2 ], and 3a were established by X-ray diffraction analyses. The 1:1 fluoride adduct of 2, [Cu I (B2bipyF)(PPh 3 ) 2 ], 2F, isolated directly from the reaction of 2 with NBu 4 F in a 4:1 mixture of CH 3 OH and CH 2 Cl 2 was characterized. All metal complexes are intensely colored and display a characteristic metal-to-ligand (B2bipy) charge transfer absorption band in the visible region, which was found to be highly sensitive toward binding by anions such as fluorides.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".