A weakly coordinating anion as a tripodal "Br3"-ligand for platinum(IV) - Structure of [(closo-CB<sub>11</sub>H<sub>6</sub>Br <sub>6</sub>)PtMe<sub>3</sub>]<sup>1</sup>
Bibliographic record
Abstract
Synthesis, structure, and NMR spectroscopic data for [(closo-CB H Br )PtMe ] are reported. This neutral platinum(IV) complex contains the closo-CB H Br anion bonded to the trimethylplatinum(IV) cation via three boron-bound bromines. Closo-CB H Br , which often acts as weakly coordinating or even non-coordinating anion, adopts here a role still very rare for this anion: it acts as a tripodal capping ligand enabling a pseudo-octahedral geometry at a d6 metal center. Three bromines from the lower hemisphere of the hexahalogenated carboranate coordinate to Pt(IV), and distortions from ideal octahedral angles at Pt are marginal (<3°). Pt-Br bond lengths are 2.7279(18), 2.7129(17), and 2.7671(18) Å. Using the J coupling constant of Pt-bonded methyl groups (79.0 Hz) as indicator of the donor strength of the tripodal cap, the prediction is obtained that closo-CB H Br is a relatively weak donor toward the trimethylplatinum(IV) cation. Ligand competition equilibria can be expected to depend on both the intrinsic donor strengths of competing ligands and on the effects of charge and geometry. We observe that closo-CB H Br is capable of replacing acetone from Me Pt(acetone) , whereas BF counterion is unable to replace acetone under similar conditions. © 2008 NRC Canada. 11 6 6 3 11 6 6 11 6 6 ptH 11 6 6 11 6 6 3 3 4 - - 2 - - + -
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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 | 0.004 | 0.006 |
| Meta-epidemiology (narrow) | 0.013 | 0.014 |
| Meta-epidemiology (broad) | 0.015 | 0.007 |
| Bibliometrics | 0.009 | 0.030 |
| Science and technology studies | 0.010 | 0.005 |
| Scholarly communication | 0.006 | 0.014 |
| Open science | 0.009 | 0.005 |
| Research integrity | 0.010 | 0.009 |
| Insufficient payload (model declined to judge) | 0.002 | 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".