Understanding the Deactivating/Activating Mechanisms in Three Optical Chemosensors Based on Crown Ether with Na<sup>+</sup>/K<sup>+</sup> Selectivity Using Quantum Chemical Tools
Bibliographic record
Abstract
Abstract The optical properties and transduction mechanisms in three reported optical chemosensors based on crown ether with selectivity turn‐on luminescence toward Na+ over K+, were investigated using Density Functional Theory/Time‐Dependent Density Functional Theory (DFT/TD‐DFT). The analysis of the structural stability of the conformers enables us to understand the optical properties of the sensors and their selectivity toward Na+. The UV‐Vis absorption and the radiative channels of the adiabatic S1 excited state were assessed. In these reported sensors, the Photoinduced Electron Transfer (PET) from the nitrogen and the oxygen (O‐atoms of the substituted N‐phenylaza group) lone pairs to fluorophore groups lead to a nonradiative deactivation process in the fluorophore to p‐conjugated anilino‐1,2,3‐triazol ionophore. This Intramolecular Charge Transfer (ICT) deactivation produced the luminescence quenching in the free sensors and K+/C1 complexes. The Na+/sensor interaction produced a Chelation Enhanced Fluorescence (CHEF) due to the inhibition of the PET and ICT, which was confirmed via the calculated oscillator strength of the emission process. The K+/sensor interaction displayed the possibility of PET in C3; however, this fact was inconclusive to affirm the quenching of luminescence, the CHEF in C2 and C3 and the selectivity toward Na+ over K+ in these systems. For this reason, simulation of the absorption and emissions spectra (calculated oscillator strength), calculation of the kinetic parameters (in charge transfers and radiative deactivations process), analysis of the metal‐ligand interaction character, and the analysis of the structural stability of the conformers were determinant factors to understand the selectivity and the optical properties of these chemosensors. The results suggest that these theoretical tools can also be used to predict the optical properties and Na+/K+ selectivity of optical chemosensors.
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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".