Bis-amino Acid Derivatives of 1,1′-Ferrocenedicarboxylic Acid: Structural, Electrochemical, and Metal Ion Binding Studies
Bibliographic record
Abstract
We report on the structural and electrochemical investigation of 1,1′-ferrocenedicarboxylic acid derivatives of tryptophan (Fc[CO-Trp-OMe] 2 - Fc-conjugate 1 ), threonine (Fc[CO-Thr-OMe] 2 – Fc-conjugate 2 ), aspartic acid (Fc[CO-Asp-OMe] 2 - Fc-conjugate 3 ) and glutamic acid (Fc[CO-GluOMe] 2 - Fc-conjugate 4 ) and their hydrolyzed analogues 1a – 4a respectively (Scheme 1 ). CD and NMR spectroscopy established 1,2′-“Herrick conformation” in solution, having intramolecular interstrand hydrogen bonds for all Fc-conjugates. However, in solid state, Fc[CO-Trp-OMe] 2 exists in “Herrick conformation” whereas Fc[CO-Thr-OMe] 2 is present in anti conformation. In solution, the involvement of indole NH of Trp and alcoholic proton of Thr in intermolecular hydrogen bonding has been explored by temperature- and concentration-dependent NMR studies. The half-wave potentials ( E 1/2 ) of ferrocene-conjugates follow the sequence 1 < 2 < 4 < 3 which is explained by the contribution of amino acid side chain functionalities toward the stability of ferrocenium ion. The CV of the Fc-conjugate 1/1a (having Trp moiety) displays two redox processes, one of which is assigned to the Fc group, and the other being related to the indole group. The oxidation peak potential of indole was found to depend strongly on the pH of the medium. The values of diffusion coefficient ( D ) and electron transfer rate constant ( k sh ) for all Fc-conjugates were determined from their corresponding cyclic voltammograms. In addition, metal ion interactions were studied with hydrolyzed Fc-conjugates 2a – 4a using CV and DPV. Upon binding to metal ions, the electrochemical changes associated with the hydrolyzed Fc-conjugates correlated to the charge density of the binding metal ion.
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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".