Obtaining accurate chemical shifts for all magnetic nuclei (<sup>1</sup>H, <sup>13</sup>C, <sup>17</sup>O, and <sup>27</sup>Al) in tris(2,4-pentanedionato-<i>O</i>,<i>O</i>′)aluminium(III) — A solid-state NMR case study
Bibliographic record
Abstract
We report a complete set of high-resolution solid-state NMR spectra for all magnetic nuclei ( 1 H, 13 C, 17 O, and 27 Al) in the α-form of tris(2,4-pentanedionato-O,O′)aluminium(III), α-Al(acac) 3 . These high-resolution NMR spectra were obtained by using a host of solid-state NMR techniques: standard cross-polarization under the magic-angle spinning (CPMAS) method for 13 C, 1-D homonuclear decoupling using the windowed DUMBO sequence for 1 H, double-rotation (DOR) for 17 O and 27 Al, and multiple-quantum MAS for 27 Al. Some experiments were performed at multiple magnetic fields. We show that the isotropic chemical shifts obtained for 1 H, 13 C, 17 O, and 27 Al nuclei in α-Al(acac) 3 are highly resolved and accurate, regardless of the nature of the targeted nuclear spins (i.e., spin-1/2 or quadrupolar) and, as such, can be treated equally in comparison with computational chemical shifts obtained from a gauge-including projector-augmented wave (GIPAW) plane-wave pseudopotential DFT method.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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; both teacher heads agree on what is shown here.
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".