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Record W1965648118 · doi:10.1021/jp040373c

Electronic and Steric Influence of Trans Axial Base on the Stereoelectronic Properties of Cobalamins

2004· article· en· W1965648118 on OpenAlex
Pawel M. Kozlowski, Marek Z. Zgierski

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 B · 2004
Typearticle
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicPorphyrin Metabolism and Disorders
Canadian institutionsSteacie Institute for Molecular Sciences
Fundersnot available
KeywordsCorrinHeterolysisHomolysisSteric effectsChemistryBond-dissociation energyBond cleavageStereochemistryDensity functional theoryBond energyDissociation (chemistry)Bond lengthCrystallographyBond orderPhotochemistryComputational chemistryCobaltMoleculeOrganic chemistryRadicalCrystal structureCatalysis

Abstract

fetched live from OpenAlex

Density functional theory (DFT) has been applied to investigate the relationship between steric and electronic properties of the trans axial base and energetics of Co−C bond cleavage in models of coenzyme B 12 . By using structurally reliable six-coordinate models, B-[Co III (corrin)]-R +, it was shown that for a given base (B) the energy of homolytic cobalt−carbon bond cleavage correctly follows the Co−C R bond lengthening. For a given axial ligand (R) the dissociation energy is very weakly dependent on the trans axial base and correlates with its basicity. Analysis of the five-coordinate homolysis products, B-[Co II (corrin)] +, shows that the Co II −N B bond length is in the range of ∼2.2 Å, slightly shorter in comparison to six-coordinate analogues, while five-coordinate heterolysis products, B-[Co III (corrin)] +2, have the Co III −N B bond significantly shorter ∼1.9 Å. This noticeable difference suggests that controlling the Co−N B bond length could be an effective way to promote biologically important homolysis of the Co−C bond in B 12 -dependent enzymes over abiological heterolysis.

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 score0.001
Threshold uncertainty score0.221

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 spread0.196 · 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