A Volumetric Study of Cyclodextrin-α,ω-Alkyl Dicarboxylate Anion Complexes in Aqueous Solutions
Bibliographic record
Abstract
The apparent molar volumes ( V φ,S ) of a homologous series of sodium α,ω-alkyl dicarboxylate [(CH 2 ) x (CO 2 Na) 2, x = 4, 6, 8, 10, 12] salts (S) have been determined in water (w) and in aqueous cyclodextrin (CD) solutions at 25 °C. The magnitude of V φ,S in ternary (w+S+CD) solutions containing β-CD and DM-β-CD (2,6-di-O-methyl β-cyclodextrin) are greater than in the binary (w+S) aqueous systems. However, in ternary solutions containing α-CD, the magnitude of V φ,S is lower than in the binary systems. The apparent molar volume (AMV) of the α,ω-alkyl dicarboxylate salts in ternary aqueous solutions can be related to the formation of inclusion complexes between the CD and the anions (C x 2- where x = 6, 8, 10, 12). The transfer volume of the C x 2- guests at infinite dilution from water to aqueous CD solutions are well described by a simple molecular additivity scheme which accounts for the number of methylene groups of the guest that are included and the number of water molecules displaced from the CD interior. The volumetric properties of the ternary systems have been quantitatively described in terms of a two- or three-site model that accounts for the AMV of bound and unbound species. In cases where CD-S inclusion complexes are formed, β-CD and DM-β-CD form 1:1, α-CD forms 1:1 ( x ≤ 8) and 2:1 complexes ( x ≥ 10). The binding mode involves threading of the methylene chain of the guest through the CD interior while the carboxylate groups remain hydrated in the bulk solvent or adjacent to the CD annuli. The calculated 1:1 binding constants ( K 1:1 ) vary between 10 1 −10 3 kg mol -1 and the 2:1 binding constants ( K 2:1 ) are ca. 10 2 kg 2 mol -2 . The relative binding affinity of the host systems with a common C x 2- guest are as follows: α-CD > β-CD > DM-β-CD, and these differences are mainly related to the diameter of the host cavity.
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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".