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Record W1982838568 · doi:10.1021/jp0122124

Twist Angles and Rotational Energy Barriers of Biphenyl and Substituted Biphenyls

2002· article· en· W1982838568 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

VenueThe Journal of Physical Chemistry A · 2002
Typearticle
Languageen
FieldChemistry
TopicMolecular Spectroscopy and Structure
Canadian institutionsUniversity of New Brunswick
Fundersnot available
KeywordsDihedral angleBiphenylTwistSteric effectsHalogenCrystallographyRotational energyChemistryMaterials scienceComputational chemistryAtomic physicsStereochemistryPhysicsGeometryMoleculeOrganic chemistryMathematics

Abstract

fetched live from OpenAlex

Using B3LYP/6-311+G* and other methods, twist angles and torsional energies were obtained for biphenyl (BP), 2-halogen BPs, 2,2‘-dihalogen BPs, and 3,3‘-dihalogen BPs, the halogens ranging from F to I. The results were compared with available gas phase and X-ray data. 2,2‘-difluoro BP has a rotational double minimum, at 57.9 and 128.9°, whereas the other 2,2‘-dihalogen BPs have a single minimum at dihedral angles ranging from 84.9 to 94.8°. All 3,3‘-dihalogen BPs have a double minimum at about 45 and 135°. Optimized twist angles and energy barriers were also calculated for 2,2‘-dimethyl BP and for perfluoro as well as perchloro BP. Most structures are accounted for by steric effects. For 2,2‘-dihalogen BPs, however, attractive forces also appear to play a role, as evidenced by the dihedral angle of 2,2‘-dichloro BP lying well below 90°.

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 score0.006
Threshold uncertainty score0.437

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)0.0000.000

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 head0.005
GPT teacher head0.202
Teacher spread0.198 · 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