chemistry- hydrogen NMR

what is the procedure of Hydrogen NMR

1. take a sample of a molecule

2. place it in an NMR spectrometer

3. wait for it to give out a spectrum

what does the number of peaks represent

number of environments

what is the standard used in hydrogen NMR

tetramethylsilane (TMS)

what are the two options of solvents used in hydrogen NMR

• solvent must contain no hydrogen atoms

• the isotope deuterium

what does the area under the peak represent

number of hydrogens in each environment

what do shift values represent

types of hydrogens in the molecule

what might happen if. hydrogen is part of multiple shifting groups

its shift value may be higher than expected

what does splitting show

number of neighbouring/ adjacent hydrogens

what does it mean if hydrogens are neighbouring

they are 3 bonds away from each other

what does a triplet show

the hydrogen environment has two neighbouring hydrogens

what does a quartet show

the environment has 3 neighbouring hydrogens

what does a singlet show

the environment has no neighbouring hydrogens

how would 1 neighbouring hydrogen be shown on a spectra

by a doublet

what does the n+1 rule exclude

hydrogens in the same environment

what types of hydrogen usually produce broad singlets that aren’t split at all

O-H and N-H

what can be added to a sample to make all O-H and N-H peaks disappear

D2O

what categories should your table include to find the structure of a molecule

1. shift

2. possible types of hydrogen

3. number of hydrogens in each environment

4. splitting

5. number of adjacent hydrogens

6. (rule out types of hydrogen that don’t match rest of data)

7. (deduce structures for each column)

8. (put structures together)