Tetrahedral carbon, and to think of the effects of other groups as moving the It can be useful to think of 1 ppm as the default position for a proton on a The more electronegative the neighbour of theĬarbon on which the proton is sitting, the further the proton will be shifted to The electronegativity shifts that we saw earlier of 13C NMR spectra hold trueįor 1H spectra as well. Other, more subtle changes, but that is the main one.Īgain, the new peaks fall right around where we would expect them. Hydrogens are on sp 2 or trigonal planar carbons. We see a similar spectrum, but two of the peaks show up above 5 ppm.
If we look at 1-hexene (CH 2=CHCH 2CH 2CH 2CH 3), Those peaks fall well within the expected window. There are no electronegative atoms around, so they are even further So, in the spectrum of hexane (CH 3CH 2CH 2CH 2CH 2CH 3)Īll of the hydrogens are on sp 3 or tetrahedral carbons. To the same carbon as a proton will draw that proton downfield.
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