Four periods in 2D experiment
Preparation spin system relaxes and then excited by r.f.
Evolution (t1) chemical shifts & spin-spin couplings evolve.
This is the timedomain which is incremented
during a 2D experiment
Mixing r.f. pulses are applied and create observable
Detection (t2) observable transverse magnetization is recorded. It is
usually labeled with t2
1. Primary 2D matrix consists a series of FIDs.
2. A set of 1D NMR spectra is obtained by Fourier transformation
with respect to t2
3. The signals of each transformation may differ in amplitude and
phase. A second Fourier transformation with respect to t1 yields
the final 2D matrix with frequency axes F1 and F2
1. 2. 3.
COSY 45. COSY 90.
COSY DQF. TOCSY.
COSY L.R. TOCSY
Relayed COSY. (with one
2D J-resolved spectroscopy
H,H- COSY Experiment
COSY & TOCSY
TOCSY of strychnine
NOESY of strychnine
C,H Correlation by Polarization Transfer
The HMQC experiment provides correlation between protons
and their attached heteronuclei through the heteronuclear
The HMBC experiment suppresses correlations via 1JC,H while
2J, 3J can be conserved.
The HSQC experiment is in fact a double INEPT experiment.
This experiment correlates protons with their directly
(G. Bodenhausen and D. J. Ruben, Chem. Phys. Lett., 69, 185 (1980)
Basic HMQC Experiment
F2 displays the doublets
with the spin coupling
constant 1J(C-H) in
addition to the H,H spin
HMQC with Decoupling
Only singlets are displayed
in F2 . These signals are
further split by H,H spin
Basic HMBC Experiment
Cross signals caused
by 1J of C-6 and C-3
are still observable
but those arising
from 3J and 2J are
Basic HSQC Experiment