Solution Behavior and Structural Diversity of Bis(dialkylphosphino)methane Complexes of Palladium
Bibliographic record
Abstract
The preparation of dipalladium complexes containing sterically nondemanding diphosphine (P-P) ligands of the type R(2)PCH(2)PR(2) where R = Me (dmpm) or Et (depm) is reported. Variable-temperature (1)H NMR spectra of the Pd(I)(2) complexes Pd(2)X(2)(dmpm)(2) (X = Cl, Br, or I; the P-P ligands in the Pd(2) complexes are always bridged, but for convenience, the micro -symbol is omitted) show the complexes to be fluxional in solution, the barriers to a ring-flipping process being DeltaG( double dagger ) = 37.9, 39.0, and 43.2 +/- 0.9 kJ mol(-)(1) for the chloro, bromo, and iodo complexes, respectively. Treatment of Pd(2)X(2)(P-P)(2) (X = Cl or Br) with X(2) generates the stable, face-to-face Pd(II)(2) derivatives trans-Pd(2)X(4)(P-P)(2), while oxidation of Pd(2)I(2)(P-P)(2) complexes with I(2) generates a new type of symmetrically di-iodo-bridged, five-coordinate complexes Pd(2)I(2)(micro -I)(2)(dmpm)(2) and Pd(2)I(2)(micro -I)(2)(depm)(2). The molecular crystal structures of four dipalladium(II) complexes are described: trans-Pd(2)Cl(4)(dmpm)(2).2CHCl(3), trans-Pd(2)Br(4)(dmpm)(2), trans-Pd(2)Cl(4)(depm)(2), and Pd(2)I(2)(micro -I)(2)(dmpm)(2). Solution NMR and UV-vis absorption spectra are consistent with the solid-state structures determined by X-ray diffraction. The stability of the dimeric Pd(II) complexes is attributed primarily to ligand steric factors.
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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) | 0.000 | 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) | 0.020 | 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".