Magnetic Circular Dichroism of Transition-Metal Complexes of Perfluorophenyl-N-Confused Porphyrins: Inverting Electronic Structure through a Proton
Bibliographic record
Abstract
Neutral and deprotonated anionic Ni(II), Pd(II), Cu(II), and Cu(III) complexes of tetrakis(perfluorophenyl)-N-confused porphyrin (PF-NCP) were prepared and investigated by UV-visible and magnetic circular dichroism (MCD) spectroscopies. As in the previously reported Ni(II) adduct of tetraphenyl N-confused porphyrin, we observe sign reverse (positive to negative intensities with increasing energy) features in the MCD spectra of the neutral Ni(II), Pd(II), and Cu(II) complexes of PF-NCP, which is indicative of rare ΔHOMO < ΔLUMO relationships. Upon deprotonation of Ni(II), Pd(II), and Cu(II) complexes, these features revert to those of more typical porphyrin MCD spectra consistent with a ΔHOMO > ΔLUMO condition. The Cu(III) PF-NCP complex shows features similar to those of the deprotonated divalent metal systems. Spectroscopic features in all target complexes as well as previously published metal-free and Ni(II) NCP systems were correlated with the density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. Calculation data are consistent with the tautomeric rearrangement of the electronic structures of NCP cores playing dominant roles, with smaller contribution from the central metal ions in the observed optical and magneto-optical properties. This is true for all described NCP systems to date, as they affect the stabilization/destabilization of the N-confused porphyrin-centered Gouterman orbitals.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".