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    Hi, could someone please explain to me with the aid of diagrams (if possible) as to how the splitting patterns in aromatic rings are produced? Like double doublets, triplet doublets, double triplets etc. I just done understand how they couple? in an aromatic system can H couple further than it can in a straight chain?

    Any help would be greatly appreciated
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    (Original post by Tori1607)
    Hi, could someone please explain to me with the aid of diagrams (if possible) as to how the splitting patterns in aromatic rings are produced? Like double doublets, triplet doublets, double triplets etc. I just done understand how they couple? in an aromatic system can H couple further than it can in a straight chain?

    Any help would be greatly appreciated
    In benzene all 6 H are equivalent and no splitting

    monosubstitution
    ----------------------

    ortho positions are equivalent 2H
    meta positions are equivalent 2H
    para position 1H

    meta protons split ortho protons into a triplet

    meta themselves are split from two directions, the ortho and the para. The ortho protons split the meta protons into a triplet and this triplet is further split by the para proton into a doublet, so you usually end up with a mess, which is actually a doublet of triplets (i.e. two lots of three peaks)

    The para proton is split into a triplet by the meta protons

    Actually, you often just end up with all of the splitting ovelapping, making it very hard to identify what goes where!
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    In practice you see ortho-coupling which is your regular 3JHH coupling and you also see W-coupling sometimes (4JHH) which is weak and is only possible because those hydrogens are firmly held in place and so have some influence on each other's magnetic field. It's best to go on a case-by-case basis, there are great differences in chemical shifts due to substituents and overlap can be very significant. For example, in monosubstituted benzenes you often see a big blob of peaks that looks like an unresolved multiplet, grouping all the aromatic H's together.
 
 
 
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