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Record W2053774265 · doi:10.1021/ja000617g

Structural, Vibrational, and Electronic Characteristics of Enyne Macrocycles as a Function of Ring Strain

2000· article· en· W2053774265 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueJournal of the American Chemical Society · 2000
Typearticle
Languageen
FieldChemistry
TopicSynthesis and Properties of Aromatic Compounds
Canadian institutionsUniversity of Alberta
FundersGoddard Space Flight Center
KeywordsBathochromic shiftChemistryRaman spectroscopyRing strainRing (chemistry)Bond lengthCrystallographyCarbon-13 NMRConjugated systemTriple bondAbsorption (acoustics)Absorption spectroscopyDouble bondMolecular geometryPhotochemistryStereochemistryMoleculePolymer chemistryCrystal structureOrganic chemistryFluorescenceOptics

Abstract

fetched live from OpenAlex

The cross-conjugated macrocycles 8a − e and acyclic model compound 12 have been synthesized and thoroughly analyzed by 1 H and 13 C NMR, UV, IR, and Raman spectroscopies, and by X-ray crystallography. The increasing ring strain and resultant changes in the double and triple bond orders are clearly detailed in the Raman and 13 C NMR spectra, as well as in the X-ray structures. Correlations between 13 C NMR shifts, bond angles, and Raman frequencies are essentially linear for the butadiynyl and olefinic moieties. The most highly strained system, 8a, displays interior alkylidene bond angles that are reduced to 108° and alkyne angles reduced to as little as 155°. The electronic absorption spectrum of 8a shows evidence of through-space homoconjugation that is manifested as a bathochromic shift of the absorption band arising from the in-plane π-system. The absorption bands from the out-of-plane π-electron systems of the more strained cycles 8a and 8b show slight bathochromic shifts as compared with the less strained systems 8c − e and acyclic 12 . Ring strain, however, has a surprisingly small effect on the electronic absorption energies of these macrocycles.

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.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.038
Threshold uncertainty score0.600

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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.

Opus teacher head0.007
GPT teacher head0.216
Teacher spread0.209 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it