Karplus equation for NMR coupling constants
E467020
The Karplus equation for NMR coupling constants is an empirical relationship that links three-bond scalar coupling values between nuclei to the dihedral angle between them, enabling the determination of molecular conformations from NMR data.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Karplus equation for NMR coupling constants canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4763388 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
Target entity: Karplus equation for NMR coupling constants Context triple: [Martin Karplus, hasWork, Karplus equation for NMR coupling constants]
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A.
Longuet-Higgins theorem in molecular symmetry
The Longuet-Higgins theorem in molecular symmetry is a fundamental result in theoretical chemistry that relates molecular symmetry properties to electronic state degeneracies and the occurrence of phenomena such as the Jahn–Teller effect.
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B.
The Nuclear Spin of the Hydrogen Molecule in the Liquid and Solid States
"The Nuclear Spin of the Hydrogen Molecule in the Liquid and Solid States" is Carl Woese’s physics doctoral thesis, which investigates how the quantum spin properties of hydrogen molecules behave and interact in condensed phases.
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C.
Herzberg–Teller approximation
The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
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D.
Heitler–London theory of the chemical bond
The Heitler–London theory of the chemical bond is an early quantum mechanical model that explains covalent bonding by treating it as the result of electron exchange and spin pairing between atoms.
-
E.
The Nature of the Chemical Bond
The Nature of the Chemical Bond is a landmark chemistry book by Linus Pauling that systematically explains chemical bonding using quantum mechanics and became one of the most influential scientific texts of the 20th century.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
Target entity: Karplus equation for NMR coupling constants Target entity description: The Karplus equation for NMR coupling constants is an empirical relationship that links three-bond scalar coupling values between nuclei to the dihedral angle between them, enabling the determination of molecular conformations from NMR data.
-
A.
Longuet-Higgins theorem in molecular symmetry
The Longuet-Higgins theorem in molecular symmetry is a fundamental result in theoretical chemistry that relates molecular symmetry properties to electronic state degeneracies and the occurrence of phenomena such as the Jahn–Teller effect.
-
B.
The Nuclear Spin of the Hydrogen Molecule in the Liquid and Solid States
"The Nuclear Spin of the Hydrogen Molecule in the Liquid and Solid States" is Carl Woese’s physics doctoral thesis, which investigates how the quantum spin properties of hydrogen molecules behave and interact in condensed phases.
-
C.
Herzberg–Teller approximation
The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
-
D.
Heitler–London theory of the chemical bond
The Heitler–London theory of the chemical bond is an early quantum mechanical model that explains covalent bonding by treating it as the result of electron exchange and spin pairing between atoms.
-
E.
The Nature of the Chemical Bond
The Nature of the Chemical Bond is a landmark chemistry book by Linus Pauling that systematically explains chemical bonding using quantum mechanics and became one of the most influential scientific texts of the 20th century.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
NMR parameter correlation
ⓘ
conformational analysis tool ⓘ empirical relationship ⓘ |
| appliesTo |
H–C–C–H dihedral angles
ⓘ
three-bond couplings across a single bond ⓘ vicinal proton–proton couplings ⓘ |
| assumes |
coupling constant is periodic in dihedral angle
ⓘ
maximum coupling near 180 degrees ⓘ minimum coupling near 90 degrees ⓘ |
| calibratedBy |
experimental NMR data
ⓘ
quantum chemical calculations ⓘ |
| category |
NMR structural restraints
ⓘ
empirical structure–property relationships ⓘ |
| dependsOn |
dihedral angle θ between coupled nuclei
ⓘ
empirical parameters A, B, and C ⓘ |
| describes |
3J spin–spin coupling constants
ⓘ
three-bond scalar coupling constants ⓘ |
| field |
nuclear magnetic resonance spectroscopy
ⓘ
physical chemistry ⓘ structural chemistry ⓘ |
| hasVariant |
Karplus equation for 3J(HN,Hα) in proteins
NERFINISHED
ⓘ
Karplus-like equations for heteronuclear couplings ⓘ generalized Karplus equation NERFINISHED ⓘ |
| historicalContext | introduced in the 1950s ⓘ |
| involves |
cosine-squared angular dependence
ⓘ
periodicity of 360 degrees in θ ⓘ |
| limitation |
accuracy decreases for highly substituted systems
ⓘ
does not explicitly include dynamic averaging ⓘ parameters are system-dependent ⓘ |
| mathematicalForm | J = A cos²(θ) + B cos(θ) + C ⓘ |
| namedAfter | Martin Karplus NERFINISHED ⓘ |
| parameter |
A
ⓘ
B ⓘ C ⓘ |
| predicts | magnitude of 3J coupling constants ⓘ |
| relatedTo |
J-coupling based structure refinement
ⓘ
Ramachandran plot analysis in proteins ⓘ |
| relates |
3J coupling constants to dihedral angles
ⓘ
NMR coupling constants to molecular conformation ⓘ |
| sensitivityTo |
bond geometry
ⓘ
electronegativity of substituents ⓘ substituent effects ⓘ |
| usedFor |
conformational analysis of organic molecules
ⓘ
determining dihedral angles from NMR data ⓘ peptide and protein structure determination ⓘ protein backbone torsion angle estimation ⓘ validating molecular dynamics simulations ⓘ |
| usedIn |
solid-state NMR adaptations
ⓘ
solution-state NMR spectroscopy ⓘ |
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Subject: Karplus equation for NMR coupling constants Description of subject: The Karplus equation for NMR coupling constants is an empirical relationship that links three-bond scalar coupling values between nuclei to the dihedral angle between them, enabling the determination of molecular conformations from NMR data.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.