Adducts of 1,4,8,11-tetraazacyclotetradecane with carboxylic acids: hydrogen-bonded supramolecular structures in two or three dimensions
Bibliographic record
Abstract
Four solvated salt-type adducts derived from cyclam (1,4,8,11-tetraazacyclotetradecane) and carboxylic acids have been structurally characterized. In the salt derived from adamantane-1-carboxylic acid, 4,11-diaza-1,8-diazoniacyclotetradecane bis(adamantane-1-carboxylate) tetrahydrate, (1) (monoclinic, P2(1)/c, Z' = 0.5), where the cation lies across a centre of inversion, the anions and the water molecules form chains of edge-fused R(4)(2)(8) and R(6)(6)(16) rings, which are linked into sheets by the cations. In the 4-aminobenzoate salt, 4,11-diaza-1,8-diazoniacyclotetradecane bis(4-aminobenzoate) monohydrate, (2) (monoclinic, C2/c, Z' = 0.5), where the cation lies across a centre of inversion and the water molecule lies across a twofold rotation axis, the cations and anions generate a three-dimensional framework, readily analysed in terms of two distinct two-dimensional substructures, viz. (10;1) sheets of R(8)(6)(46) rings, and pairwise interwoven (100) sheets, reinforced by water molecules. The 3-hydroxybenzoate salt, 4,11-diaza-1,8-diazoniacyclotetradecane bis(3-hydroxybenzoate) dihydrate, (3) (monoclinic, Pc, Z' = 1), contains a three-dimensional framework constructed from anions and water molecules only, which encapsulates large voids and within which the cations are linked to the anion-water framework via N-H.O hydrogen bonds. There are two independent cations in 4,11-diaza-1,8-diazoniacyclotetradecane 5-hydroxyisophthalate(2-) methanol solvate, (4) (monoclinic, P2(1)/c, Z' = 1), both lying across centres of inversion but with entirely different configurations. The anions alone form simple chains, and these chains are linked by the two types of cation into a three-dimensional framework from which the methanol molecules are pendent. Comparisons are made with carboxylate complexes of the [Ni(cyclam)](2+) cation and with carboxylate salts derived from meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane.
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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".