Surface Enhanced Infrared Absorption Spectroscopy Studies of DMAP Adsorption on Gold Surfaces
Bibliographic record
Abstract
Attenuated total reflectance surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) measurements have been employed to study the adsorption of dimethylaminopyridine (DMAP) and its conjugate acid (DMAPH+) on gold surfaces as a function of applied potential and solution pH. Based on our transmission measurements, we have been able to demonstrate that the acid/base forms of this pyridine derivative can be readily differentiated due to their distinct IR signals. When the solution pH is equal to the pKa of DMAPH+, we demonstrate that the adsorbing species is DMAP, oriented with its heterocyclic ring perpendicular to the electrode surface. In acidic electrolytes, our SEIRAS data provide direct spectroscopic evidence of DMAP monolayer formation even though the pH is 5 units below the pKa of the conjugate acid. Our data support a potential induced deprotonation of the endocyclic nitrogen and resulting coordination of the nitrogen lone pair to the gold surface. Both of these results confirm our existing model of DMAP adsorption previously based solely on electrochemical measurements. However, the present SEIRAS study also indicates that, at low pH, DMAPH+ can electrostatically coordinate to very negatively charged surfaces. This mode of adsorption was previously unobserved, illustrating the ability of in situ spectroscopic techniques to reveal new information that is not apparent from traditional electrochemical techniques such as differential capacity and chronocoulometry.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".