Octanol/water distribution coefficients of the C~1~ through C~7~ perfluoro-n-alkyl sulfonates: Comparison of the IEFPCM-UFF, CPCM, and SMD solvation models
Bibliographic record
Abstract
Abstract The octanol/water distribution coefficients (log D~ow~) of the C~1~ through C~7~ perfluoro-n-alkyl sulfonates (PFSAs) were calculated using the M062X/6-311++G(d,p) and MP2/6-311++G(d,p)//M062X/6-311++G(d,p) levels of theory and the IEFPCM-UFF, CPCM, and SMD solvation models. At both levels of theory with all solvation models, absolute log D~ow~ calculated for the straight chain C~1~ through C~7~ PFSAs display a substantial negative bias against available experimental data and expected trends by several log units. However, the SMD solvation model achieves accurate relative log D~ow~ accuracy, yielding fragmental contributions of a -CF~2~- group towards the log D~ow~ of 0.51+/-0.02 to 0.54+/-0.01 units (-3.0+/-0.1 to -3.1+/-0.1 kJ/mol), in good agreement with the experimental value of 0.61 units (-3.4+/-0.1 kJ/mol). In contrast, the IEFPCM-UFF and CPCM solvation models exhibit either invariant log D~ow~ with increasing perfluoro-n-alkyl chain length (CPCM) or a modestly decreasing trend (IEFPCM-UFF).
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 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| Open science | 0.001 | 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".