Molecular Dynamics and <i>ab Initio</i> Studies of the Effects of Substituent Groups on the Thermodynamic Properties and Structure of Four Selected Imidazolium-Based [Tf<sub>2</sub>N<sup>–</sup>] Ionic Liquids
Bibliographic record
Abstract
All-atom molecular dynamics simulations combined with ab initio calculations are used to study the thermodynamic properties and microscopic structure of four ionic liquids (ILs) based on the imidazolium cation with different alkyl side branches, ([bmmim] +, 1-butyl-2,3-dimethylimidazolium; [bmim] +, 1-butyl-3-methylimidazolium; [apmim] +, 1-(3-aminopropyl)-3-methylimidazolium; [mim] +, 1-methylimidazolium), paired with the [(CF 3 SO 2 ) 2 N] −, bis(trifluoromethanesulfonyl)imide anion, in the temperature range of (298 to 600) K. We observed the highest value of the molar internal energy, enthalpy of vaporization, and cohesive energy density for the amine-functionalized [apmim][Tf 2 N] ionic liquid. Structural analysis shows that the amine functionalization of the end of the alkyl side chain of imidazolium cation does not significantly affect the organization of [Tf 2 N] − around [apmim] +, but additional NH 2 groups lead to short-range cation–cation structural correlations between neighboring [apmim] + . The C2 methylation extensively affects preferential out-of-plane face-to-face locations of [Tf 2 N] − around [bmmim] + and also the cation–cation distributions. [mim][Tf 2 N] has the highest simulated density and better packing efficiency of liquid phase in comparison with other studied ILs. The strongest first shell probability density region of [mim] + neighbors above and below the imidazolium ring of the reference cation represents better π–π stacking in the liquid phase of this ionic liquid. The presented results determine the role of the cation structure on the properties of this family of ILs. Good agreement was achieved between simulation results of the bulk phase and quantum calculations which are performed to determine the optimized structure of isolated ion pairs in chosen configurations and the strength of cation–anion interactions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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 | 0.001 | 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".