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are empirically derived parameters whose values depend on the atoms and substituents involved. The relationship may be expressed in a variety of equivalent ways e.g. involving cos 2φ rather than cos φ —these lead to different numerical values of
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coupling constants. The superscript "3" indicates that a H atom is coupled to another H atom three bonds away, via H-C-C-H bonds. (Such hydrogens bonded to neighbouring carbon atoms are termed
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Minch, M. J. (1994). "Orientational
Dependence of Vicinal Proton-Proton NMR Coupling Constants: The Karplus Relationship".
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This relationship between local geometry and coupling constant is of great value throughout
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Karplus, Martin (1959). "Contact
Electron-Spin Coupling of Nuclear Magnetic Moments".
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Karplus, Martin (1963). "Vicinal Proton
Coupling in Nuclear Magnetic Resonance".
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27:(φ) = 12 cosφ - cosφ+2 obtained for ethane derivatives
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Generalized
Karplus calculation of proton-proton coupling constants
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spectroscopy and is particularly valuable for determining
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117:{\displaystyle J(\phi )=A\cos ^{2}\phi +B\cos \,\phi +C}
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184:but do not change the nature of the relationship.
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49:nuclear magnetic resonance spectroscopy
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39:, describes the correlation between
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266:Chemical & Engineering News
233:Concepts in Magnetic Resonance
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20:Graph of the Karplus relation
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259:Dalton, Louisa (2003-12-22).
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187:The relationship is used for
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382:Nuclear magnetic resonance
203:nuclear magnetic resonance
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45:dihedral torsion angles
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367:Karplus equations app
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148:{\displaystyle \phi }
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309:1959JChPh..30...11K
135:coupling constant,
261:"Karplus Equation"
209:torsion angles in
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211:protein NMR
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217:References
41:J-coupling
240:: 41–56.
213:studies.
143:ϕ
106:ϕ
93:ϕ
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68:ϕ
376:Category
207:backbone
305:Bibcode
196:vicinal
155:is the
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182:C
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133:J
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112:C
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99:B
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85:2
77:A
74:=
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65:(
62:J
22:J
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