thors.lab
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H-NMR Multiplicity of aldehyde hydrogen on 3-fluorobenzaldehyde
So I would suspect the aldehyde hydrogen on 3-fluorobenzaldehyde to be a singlet right? The adjacent carbon has no hydrogens attached. But the
ChemAxon chemicalize calculator says that would be a triplet:
Why? Is this something to do with the conjugated system?
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DraconicAcid
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Yes, you can sometimes get what is called "W-coupling".
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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thors.lab
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Awesome, thank you!
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AvBaeyer
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The multiplicity is a result of long distance coupling with the fluorine atom. H-F couplings occur through several bonds. Any good NMR text will give
you an explanation with examples.
AvB
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DraconicAcid
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Quote: Originally posted by AvBaeyer | The multiplicity is a result of long distance coupling with the fluorine atom. H-F couplings occur through several bonds. Any good NMR text will give
you an explanation with examples.
AvB |
No, because it's a triplet. If it was coupling to the F, it would be a doublet.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Sigmatropic
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W coupling would be 4J, in this example it is 5J. So no W coupling. Also in reality it is a doublet, see attachment, so I second avbaeyer. Source:Sigma aldrich
Attachment: FNMR010527.PDF (99kB) This file has been downloaded 284 times
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