Observations on the Mechanochemical Insertion of Zinc(II), Copper(II), Magnesium(II), and Select Other Metal(II) Ions into Porphyrins
Bibliographic record
Abstract
Building on a proof of concept study that showed the possibility of the mechanochemical insertion of some M(II) metals into meso -tetraphenylporphyrin using a ball mill as an alternative to traditional solution-based methods, we present here a detailed study of the influence of the many experimental variables on the reaction outcome performed in a planetary mill. Using primarily the mechanochemical zinc, copper, and magnesium insertion reactions, the scope and limits of the type of porphyrins (electron-rich or electron-poor meso -tetraarylporphyrins, synthetic or naturally occurring octaalkylporphyrins, and meso -triphenylcorrole) and metal ion sources suitable for this metal insertion modality were determined. We demonstrate the influence of the experimental metal insertion parameters, such as ball mill speed and reaction time, and investigated the often surprising roles of a variety of grinding agents. Also, the mechanochemical reaction conditions that remove zinc from a zinc porphyrin complex or exchange it for copper were studied. Using some standardized conditions, we also screened the feasibility of a number of other metal(II) insertion reactions (VO, Ni, Fe, Co, Ag, Cd, Pd, Pt, Pb). The underlying factors determining the rates of the insertion reactions were found to be complex and not always readily predictable. Some findings of fundamental significance for the mechanistic understanding of the mechanochemical insertion of metal ions into porphyrins are highlighted. Particularly the mechanochemical insertion of Mg(II) is a mild alternative to established solution methods. The work provides a baseline from which the practitioner may start to evaluate the mechanochemical metal insertion into porphyrins using a planetary ball mill.
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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".