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Due to the decoupling in 13 C NMR, the number of absorptions due to aromatic carbons can easily be observed. This can be used to determine the relative positions (ortho, meta, or para) for di-substituted benzenes.
Therefore, it is important to pay attention to the meta-position in the NMR (Nuclear Magnetic Resonance) of the benzene ring. This is called meta-coupling, and when the meta-position of the benzene ring contains a hydrogen atom, the J-value is usually between 1 and 3 Hz.
I got a huge OChem final tomorrow and need to know how to identify whether something is ortho, para or meta from an H-NMR spectrum. We didn't cover this in class and I'm having trouble finding an answer for this online.
29 Ιαν 2018 · In one pattern, ortho- and para– products dominate, and the meta-product is an extremely minor byproduct. Substituents which lead to this result are called, “ ortho-, para- directors”. Examples of ortho-, para – directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens.
In the following practice problems, we will go over the ortho-, para-, and meta – directors in Electrophilic Aromatic Substitution. The first exercise is to make sure you know which groups are activators and deactivators as well as how that relates to the Ortho-, Para-, and Meta – directing effects.
Ortho hydrogens on a benzene ring couple at 6-10 Hz, while 4-bond coupling of up to 4 Hz is sometimes seen between meta hydrogens. Fine (2-3 Hz) coupling is often seen between an aldehyde proton and a three-bond neighbor.
1 Μαΐ 2016 · We examine numerous example spectra and learn how the position of C-H wagging peaks, and the presence or absence of a ring-bending peak, allow one to distinguish between mono-, ortho-, meta-, and para-substituted rings most of the time.
