Chemical bonding and aromaticity in metalloporphyrins<sup>,</sup>
Bibliographic record
Abstract
We report here the chemical bonding and aromaticity patterns in metalloporphyrins, which were obtained with density functional theory (DFT) calculations at the OPBE/TZP level. This level of theory was previously shown to be very accurate for determining spin-state splittings [J. Chem. Theory Comput. 2008, 4, 2057] of transition-metal complexes. We considered metalloporphyrins along the first-row transition metals (Sc–Zn) extended with alkaline-earth metals (Mg, Ca) and several second-row transition metals (Ru, Pd, Ag, Cd). An energy decomposition analysis was performed to study the metal–ligand interactions, which showed that almost all complexes are significantly stabilized through (covalent) orbital interactions. The only exception is with calcium as the central metal, which interacts with the porphyrin mainly through electrostatic interactions. Furthermore, we studied aromaticity patterns for these complexes by looking at a number of (structural and electronic) aromaticity descriptors, for both the inner-ring and outer-ring of the porphyrin and of the pyrroles. The inner-ring (N16) aromaticity is shown to be unaffected by metal complexation, while the outer-ring (N20) and the pyrrole (N5) aromaticities are found to increase significantly in the metal coordinated porphyrins.
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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) | 0.002 | 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".