Linking Hydrogen Dicarboxylate Synthons with Substituted Guanidinium Cations: Transforming Rings and Chains into Two- and Three-Dimensional Structures
Bibliographic record
Abstract
Hydrogen-bonding interactions between N,N ‘, N ‘ ‘-trisubstituted guanidinium cations and hydrogen dicarboxylates are explored. The extended structures of these compounds combine established structural motifs for the hydrogen carboxylate anions with C 3 -symmetric guanidinium links. Both N,N ‘, N ‘ ‘-triisopropylguanidine (TPG) and N,N ‘ -diisopropyl- N ‘ ‘-pentafluorophenylguanidine (DPArG) react in 1:1 stoichiometry with oxalic acid to yield compounds that were crystallized from tetrahydrofuran (THF) to give (TPGH)(C 2 O 4 H)(THF) 0.5 ( 1 ) and (DPArGH)C 2 O 4 H(THF) ( 2 ). Compound 1 displayed hydrogen oxalate dimers ( (10) motif) that are bridged with the TPGH + cation to yield an open three-dimensional (3-D) structure that crystallized around occluded THF. In the case of compound 2, the targeted (DPArGH)(C 2 O 4 H) incorporated an additional hydrogen-bonded THF molecule to provide a structure in which the - O 2 CCOOH anion exhibited head-to-tail chains (C(5) motif) that are cross-linked through hydrogen bonds with [(DPArGH)(THF)] + to yield two-dimensional (2-D) layers that stack along the c -axis. TPG also reacts stoichiometrically with succinic (butanedioic) acid and maleic ( cis -2-butenedioic) acid to produce guanidinium hydrogen dicarboxylate salts (TPGH + )( - O 2 CC 2 H 4 CO 2 H) ( 3 ) and (TPGH + )( - O 2 CCH CHCO 2 H) ( 4 ). The primary structure of 3 combines head-to-tail hydrogen-bonded chains of monoanionic dicarboxylic acids with chain-spanning planar TPGH + cations to give a cross-linked ladder motif that ultimately generates a 3-D net. In the case of 4, the hydrogen maleate anion displayed a characteristic intramolecular, low barrier hydrogen bond (LBHB) (S(7) motif). Hydrogen bonding between planar TPGH + and the cyclic, planar anion leads to a layered solid-state structure consisting of a corrugated 2-D net constructed from 16- and 42-membered rings.
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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) | 0.000 | 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) | 0.000 | 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".