A computational investigation of J couplings involving 27Al, 17O, and 31P
Bibliographic record
Abstract
Indirect nuclear spin-spin (J) couplings between (31)P, (27)Al, and (17)O are computed for Cl(3)POAlCl(3), Ph(3)PO, Ph(3)PAlCl(3), Al(H(2)O)(6)(3+), an aluminophosphate model system, and grossite model systems, using the B3LYP hybrid functional and the pcJ-n and aug-pcJ-n basis sets. The results provide computational corroboration of the existence of J coupling constants between (31)P, (17)O, and (27)Al of suitable magnitude for INEPT-style experiments in which connectivity is established as a result of magnetization transfer using these couplings. Potentially useful correlations between structure (bond lengths, angles, dihedrals) and the coupling constants (1)J((27)Al, (17)O), (1)J((31)P, (17)O), and (2)J((31)P, (27)Al) are presented. Calculated values of near zero for both (1)J((27)Al, (17)O) and (2)J((31)P, (27)Al), depending on the molecule and the geometry, suggest that some structurally important correlations could be absent in NMR spectra which rely on magnetization transfers solely based on these isotropic coupling constants.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".