Hydridodimethylplatinum(IV) Complexes with Bis(pyridine) Ligands: Effect of Chelate Ring Size on Reactivity
Bibliographic record
Abstract
The effect of changing the bite angle of the dipyridyl ligand LL on the reactivity of the dimethylplatinum(II) complexes [PtMe 2 (LL)] has been studied, by comparing complexes with the ligands LL = di-2-pyridylamine (DPA) or di-2-pyridyl ketone (DPK), which form a six-membered chelate ring, to compounds with 2,2‘-bipyridyl derivatives, which form a five-membered chelate ring. The complex [PtMe 2 (DPA)] undergoes easy oxidative addition of methyl iodide to give the corresponding platinum(IV) complex [PtIMe 3 (DPA)]. Both [PtMe 2 (DPA)] and [PtMe 2 (DPK)] are protonated by acids HX at low temperature to give the hydridodimethylplatinum(IV) complexes [PtHXMe 2 (NN)] and [PtH(S)Me 2 (NN)]X (S = solvent), which can exist in two isomeric forms with H trans to X or N. The structure of the complex [PtHClMe 2 (DPK)] was determined crystallographically. In a solution containing excess CD 3 OD, extensive hydrogen/deuterium exchange occurs into the methylplatinum groups and methane product at low temperature, indicating very easy reversibility of the exchange between hydridomethylplatinum(IV) and (methane)platinum(II) complexes. The hydridomethylplatinum(IV) complexes reductively eliminate methane at room temperature in solution but have significantly higher thermal stability and undergo more extensive H−D exchange than when NN = 2,2‘-bipyridyl. The reaction of [PtMe 2 (DPA)] with excess HCl gave [PtCl 2 (DPA)], and the reaction of [PtMe 2 (DPK)] with excess CF 3 SO 3 H gave the aqua complex [Pt(OH 2 ) 2 (DPK)](CF 3 SO 3 ) 2 or the binuclear hydroxo complex [Pt 2 (μ-OH) 2 (DPK) 2 ](CF 3 SO 3 ) 2, depending on the experimental conditions.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".