Theoretical prediction of O–H, Si–H, and Si–C σ-bond activation reactions by titanium(IV)–imido complex
Bibliographic record
Abstract
The O–H σ-bond activation of methanol, the Si–H σ-bond activation of silane, and the Si–C σ-bond activation of methylsilane by titanium(IV)–imido complex (Me 3 SiO) 2 Ti(NSiMe 3 ) were theoretically investigated with DFT and MP2 to MP4(SDQ) methods. The O–H σ-bond activation of methanol occurs with small activation barrier (E a ) of 7.1 (14.6) kcal/mol and large exothermicity (E exo ) of 65.8 (61.4) kcal/mol to afford (Me 3 SiO) 2 Ti(OCH 3 )[NH(SiMe 3 )], indicating that the O–H σ-bond activation occurs easier than the C–H σ-bond activation (E a = 14.6 (21.5) kcal/mol and E exo = 22.7 (16.5) kcal/mol), where DFT- and MP4(SDQ)-calculated values are presented without and in parenthesis hereafter. Though the OCH 3 group becomes anionic and the H atom becomes proton-like in this activation reaction, population changes more moderately occur than those of the C–H σ-bond activation. This is because the H–OCH 3 bond is already polarized in methanol. In the Si–H σ-bond activation, two reaction courses were investigated; in one course, the product is (Me 3 SiO) 2 Ti(SiH 3 )[NH(SiMe 3 )] in which the H atom and the SiH 3 group are bound to the N atom and the Ti center, respectively, while in the other course the product is (Me 3 SiO) 2 Ti(H)[N(SiH 3 )(SiMe 3 )] in which the H atom and the SiH 3 group are bound to the Ti center and the imido N atom, respectively. Though the former reaction occurs with small E a value and large exothermicity, the latter reaction occurs easier with further smaller E a value of 2.6 (4.3) kcal/mol and larger E exo value of 32.5 (34.1) kcal/mol than those of the former reaction. This is because the Ti–H bond energy is much larger than the Ti–SiH 3 one. The Si–C σ-bond activation occurs with moderate activation barrier of 19.1 (18.6) kcal/mol and considerably large exothermicity of 33.9 (37.7) kcal/mol. Based on these results, we wish to propose the theoretical prediction that the titanium(IV)–imido complex is useful for O–H, Si–H, and Si–C σ-bond activation reactions.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".