New Insights into the Stoichiometric and Catalytic Reactivity of Unsaturated Pd<sub>3</sub>(dppm)<sub>3</sub>CO<sup><i>n</i>+</sup> Clusters (<i>n</i> = 0, 1) Towards Halocarbons – First Evidence for Inorganic By‐Products
Bibliographic record
Abstract
Abstract The title clusters, Pd3(dppm)3(CO)+ and Pd3(dppm)3(CO)0 can be electrochemically generated from the 1‐ and 2‐electron reductions, respectively, of the Pd3(dppm)3(CO)2+ cluster [dppm = bis(diphenylphosphanyl)methane; Pd32+]. Pd3+ reacts in a stoichiometric ratio with methyl iodide, MeI, and benzyl bromide, BzBr, in THF to provide the corresponding Pd3(X)+ adducts (X = I, Br respectively) as inorganic products. Other products are Bz2 and PhMe for BzBr but, for MeI, no organic product was observed (since they are too volatile). In the presence of the same substrates, Pd30 also reacts in a stoichiometric ratio to form the same organics and the Pd3‐(X)+ adducts (X = I and Br). However for MeI, the major inorganic product is the A‐frame Pd2(dppm)2(Me)2I+ binuclear complex. For BzBr, the corresponding A‐frame complex Pd2(dppm)2(Bz)2Br+ could not be detected. The spin‐trap agents, 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO) and 5,5′‐dimethyl‐1‐pyrroline N‐oxide (DMPO), have been used to demonstrate the intermediacy of the radical Bz·. The catalytic generation of “Bz·” was performed using two methods, i.e. 1) using a copper anode as the working electrode [Pd3‐(Br)+ + Cu – e– → Pd32+ + CuBr (s)] and 2) using a carbon cathode as the working electrode [Pd3(Br)+ + 2e– → Pd30 + Br–]. The chemical yields for Bz2 vary between 50 and 56 % and the Faradic yield is of the order of 90 % for method 1 and between 52 and 59 % for method 2 [taking into account the quantity of electricity necessary to reduce the catalyst Pd3‐(Br)+]. The X‐ray structure of Pd3(dppm)3(CO)(Br)+ is presented and the following parameters were recorded: monoclinic space group P21/n, a = 10.6546(2), b = 37.1091(7), c = 21.2714(7) Å, β = 91.55(1)o, V = 8407.3(4) Å3, Z = 4, R1 = 0.0581 [I > 2σ(I)], wR2 = 0.1478 (all data). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
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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 | 0.000 |
| 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) | 0.001 | 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".