Theoretical Investigation of the Apparently Irregular Behavior\nof Pt−Pt Nuclear Spin−Spin Coupling Constants
Bibliographic record
Abstract
One-bond Pt−Pt nuclear spin−spin coupling constants <i>J</i>(Pt−Pt) for closely related dinuclear Pt\ncomplexes can differ by an order of magnitude without any obvious correlation with Pt−Pt distances. As\nrepresentative examples, the spin−spin couplings of the dinuclear Pt<sup>I</sup> complexes [Pt<sub>2</sub>(CO)<sub>6</sub>]<sup>2+</sup> (<b>1</b>) and\n[Pt<sub>2</sub>(CO)<sub>2</sub>Cl<sub>4</sub>]<sup>2-</sup> (<b>2</b>) have been computationally studied with a recently developed relativistic density functional\nmethod. The experimental values are <sup>1</sup><i>J</i>(<sup>195</sup>Pt−<sup>195</sup>Pt) = 5250 Hz for <b>2</b> but 551 Hz for <b>1</b>. Many other examples\nare known in the literature. The experimental trends are well reproduced by the computations and can be\nexplained based on the nature of the ligands that are coordinated to the Pt−Pt fragment. The difference\nfor <i>J</i>(Pt−Pt) of an order of magnitude is caused by a sensitive interplay between the influence of different\nligands on the Pt−Pt bond, and relativistic effects on metal−metal and metal−ligand bonds as well as on\n“atomic orbital contributions” to the nuclear spin−spin coupling constants. The results can be intuitively\nrationalized with the help of a simple qualitative molecular orbital diagram.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.341 | 0.001 |
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".