Year 12s: what will be the first way you research your future options? >>

nmr question

how come for the protons labelled b, the splitting pattern is a singlet and not a triplet. since it is next to a ch2 group nmr question.jpg

because the carbon above it is attached to an OH group and no other hydrogens I'm pretty sure

(edited 3 years ago)

Reply 3

KiTt3n__1234

Original post by krunker555

because the carbon above it is attached to an OH group and no other hydrogens I'm pretty sure

But it's still adjacent to a carbon with 2 hydrogens on it, the proton on the OH would give a singlet peak, but I don't think it's the reason why the b group is a singlet

Reply 4

krunker555

Original post by KiTt3n__1234

But it's still adjacent to a carbon with 2 hydrogens on it, the proton on the OH would give a singlet peak, but I don't think it's the reason why the b group is a singlet

what? no the b CH3 group is adjacent to the carbon that has no hydrogens bonded to it. It's adjacent to the same carbon that the OH group is adjacent to, hence it would show no splitting pattern.

Reply 5

username1625799

Original post by dasda

how come for the protons labelled b, the splitting pattern is a singlet and not a triplet. since it is next to a ch2 group nmr question.jpg

It's adjacent to a C with an OH group and a CH3 group hence only singlet. Whereas the proton in the middle carbon is adjacent to another proton (either the one above or the one below vice versa) hence this would give a doublet

Reply 6

emopotatodragon

Original post by dasda

how come for the protons labelled b, the splitting pattern is a singlet and not a triplet. since it is next to a ch2 group nmr question.jpg

The next carbon attached to b has no protons attached DIRECTLY to it, it has a hydroxy and methyl group, hence 0+1 = singlet :smile:

Thanks i understand

Original post by dasda

Thanks i understand

When looking for splitting, you're looking for H - C - C - H. If you haven't got that, you ain't got splitting.

Reply 9

KiTt3n__1234

Original post by krunker555

what? no the b CH3 group is adjacent to the carbon that has no hydrogens bonded to it. It's adjacent to the same carbon that the OH group is adjacent to, hence it would show no splitting pattern.