Guanine tetrads: an IRMPD spectroscopy, energy resolved SORI-CID, and computational study of M(9-ethylguanine)<sub>4</sub><sup>+</sup>(M = Li, Na, K, Rb, Cs) in the gas phase
Bibliographic record
Abstract
The intrinsic properties of the alkali metal cationized G-tetrads, M(9eG)4(+) (M = Li, Na, K, Rb, Cs) composed of 9-ethylguanine (9eG), were studied by a combination of mass spectrometric techniques. The gas phase structures were probed by infrared multiple photon dissociation (IRMPD) spectroscopy in both the fingerprint region (900-1850 cm(-1)) and the N-H/C-H stretching region (2700-3800 cm(-1)). The gas phase structures were found to be similar for all five complexes and most consistent with the metal-centred G-tetrad structure. Energy-resolved CID was also used to compare the gas phase stabilities of the G-tetrads and showed that Na(9eG)4(+) was more stable than Li(9eG)4(+) followed by the K(+), Rb(+), and Cs(+) G-tetrads in order. The experimental energy ordering was reproduced by electronic structure calculations of the energies. Furthermore, the computations also showed that the lower stability to loss of 9-ethylguanine for the Li(+) complex could be due to a strong destabilization of the neutral G-tetrad due to the persistence toward maximizing the ion-dipole interactions while also maintaining hydrogen bonding interactions.
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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) | 0.001 | 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 | 0.001 |
| 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".