Assessing and characterizing the inductive effect through silicon containing backbones and on silicon reactivity
Bibliographic record
Abstract
This thesis describes a study of the inductive effect in derivatives of bicyclo[1.1.1.]pentane; chosen because it eliminates any possibility of conjugation between the substituent and probe, and keeps the steric effect constant by providing a rigid backbone. The substituent effects, both upon a silicon center and transmitting through silicon atoms, in these systems were studied using Density Functional Theory and the isodesmic reaction approach to Hammett's methods. The elctron density distribution was analyzed using the Quantum Theory of Atoms in Molecules. \nAlthough less sensitive to substitution, it was discovered that the effect as \nmeasured on a Si?probe (?Si(OH)3) is the same as that measured using a C?probe (?COOH). In both cases, the transmission of the ?so?called? inductive effect appears to operate in the same fashion: through the molecule using the atomic dipole moment. The x?component (axis connecting the substituent and probe) of the substituent dipole \nwas determined to be the controlling property. Despite minor differences in structure, replacing the backbone atoms with silicon appears to have little effect upon the mechanism of transmission, but a general decrease in sensitivity, to the effect of substitution, is apparent. As the atomic dipole moment conforms to the principle of atomic transferability, it is possible to describe the inductive effect in terms of the substituent?only dipole (?x(RH); determined for the RH system). In fact, we were able to \nreplace the substituent constant, an empirically derived parameter, with ?x(RH), a quantum mechanically derived parameter. Linear free energy relationships to describe the inductive effect with ?x(RH), as well as an electronegativity term and steric terms to describe the backbone and probe, were developed that essentially recreate the entire substituent effect.
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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) | 0.000 | 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 | 0.000 |
| 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 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".