The Structures and Stabilities of the Complexes of Biologically Available Ligands with Fe(II) Porphine: An Ab Initio Study
Bibliographic record
Abstract
Fe(II) porphine complexes were investigated at the “MP2/LB”//B3LYP/SB level of theory where SB and LB denote the small and large basis sets, 6-31+G(d) and 6-311+G(2df,2p), respectively. Solvation effects due to water and benzene were approximated by the IEFPCM procedure. Ligands included H 2 O, Cl –, and OH – and Im (imidazole), CH 3 NH 2, (CH 3 ) 2 S, CH 3 CO 2 –, CH 3 S –, and CH 3 PhO – as models of the side chains of His, Lys, Met, Asp/Glu, Cys, and Tyr residues, respectively. Fe(II) porphine, 2, and the complexes 2 (H 2 O), 2 (Im), 2 (CH 3 ) 2 S), 2 (CH 3 NH 2 ), and 2 (H 2 O) 2 have triplet ground states. All pentacoordinated complexes of 2 with negatively charged ligands have high spin quintet ground states, while all hexacoodinated complexes with at least one Im ligand have low spin singlet ground states. With the exception of 2 (Im) 2 and 2 (Im)((CH 3 ) 2 S), no hexacoordinated complexes are stable in water or benzene. Redox properties are sensitive to the nature of the environment and the ligand(s) attached to the iron center. With the exception of the parent system, 2 + / 2, all complexes are predicted to have a negative reduction potential relative to the standard hydrogen electrode in water. With neutral ligand(s), the reduction potential is higher in the nonpolar environment. The opposite is true with negatively charged ligands. The redox activity of cytochromes, peroxidases, and catalases is discussed in the context of the model parent systems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".