Crystal chemistry of tetraradial species. Part 10. Tilting at windmills: conformations of the tetraphenyl species ZPh<sub>4</sub><sup>0, ±1</sup> (Z = B, C, N)
Bibliographic record
Abstract
The equilibrium geometries of the isoelectronic ZPh 4 0, ±1 (Z = B, C, N) molecules have been optimized, in S 4 and D 2 d symmetries, at the HF/6-31G(d,p) and B3LYP/6-31G(d,p) levels, with the phenyl rings constrained to be planar. The ground-state conformations of all three species are shown to be of S 4 symmetry, but the difference of the energies of the S 4 and the D 2 d conformations is estimated to amount to only ~1 kcal mol 1 , with a barrier to concerted rotational reorientation of the phenyl rings of ~5.0 kcal mol 1 for BPh 4 , ~6.4 kcal mol 1 for CPh 4 , and ~7.9 kcal mol 1 for NPh + 4 . A redetermination of the crystal structure of CPh 4 from 60°C X-ray data agrees with the results of previous determinations at ambient temperature; the CPh 4 molecule in the crystal is slightly compressed along the S 4 axis relative to the free molecule, otherwise the geometries of the two are essentially the same. Correlations between the optimized geometric parameters of the ZPh 4 0, ±1 molecules have been examined and analyzed in detail, as have the substitution-induced changes in the geometry of the phenyl ring. The results confirm and strengthen the conclusions from the statistical studies by Domenicano et al. on the geometry of benzene rings monosubstituted by atoms of elements from the first row of the Periodic system.Key words: tetraphenylborate, tetraphenylmethane, tetraphenylammonium, ab initio molecular geometries.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 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".