The 2D Heteronuclear NOESY (HOESY) experiment allows
to detect heteronuclear through-space NOE connectivies between nonbonded
nuclei. This is the heteronuclear version of the NOESY experiment.
REQUIREMENTS
Easy implementation on any AVANCE spectrometer.
VERSIONS
The basic pulse sequence of the HOESY experiment
(
83JACS5167
,
83JACS6994
,
84JACS6533
, and
86JMR344-69
)
is closely related to the conventional NOESY pulse sequence. After a 90º
1H pulse, transverse magnetization evolves during the variable evolution
period under heteronuclear decoupling. A second 90º 1H pulse
creates longitudinal magnetization and, during the mixing time, polarization
transfer via dipolar coupling takes place. A final 90º 13C pulse creates
transverse magnetization which is detected under broadband proton decoupling.
Other modified versions have been proposed:
Suppression of strong local NOEs
(
88MRC181
)
Suppression of undesired virtual NOE correlations due to strong H-H couplings
(
87JMR397-74
,
88JMR539-80
,
91JMR152-92
,
90JMR364-88
, and
99JMR89-138
).
Sensitivity-improved detection of NOEs on nonprotonated carbon with long
T1 relaxation
(
88JMR45-79
,
88JMR206-79
, and
89JMR585-84
).
H-H decoupling in the F1 dimension by applying constant-time periods
(
89MRC396
).
w1-X-filtered HOESY experiment for detecting intermolecular contacts between
identical sites
(
95JACS10405
).
HOESY experiments have been applied to study surfactant systems
(
92JACS6190
,
92JPC1011
,
93JPC2764
, and
93JCP4775
).
Related experiments based on heteronuclear cross-polarization
(
92JMR139-100
).
However, strong TOCSY contributions appear in the final spectrum.
Quantitative distance can also be obtained as known for NOESY experiments
(
86JMR538-69
).
Theoretical and practical aspects of 2D HOESY experiments have been reviewed
(
87PROG223
).
Applications of 1H-19F HOESY
To probe solvent -solute interactions in biomacromolecules
(
95JB415
and
96JMRA83-121
)
.
Study of ion-pairing in inorganic and organometallic copmplexes
(
03EJIC195
)
EXPERIMENTAL DETAILS
The 2D HOESY experiment can be recorded in routine/automation
modes. The most important parameter to optimize is the mixing time
(
86JMR344-69
).
More details on practical implementation of the 2D HOESY experiment
on AVANCE spectrometers can be found in
The 2D HOESY spectrum is an heteronuclear correlation map in
which cross-peaks are due to heteronuclear NOE enhancements. However, strong
direct heteronuclear NOEs, undesired virtual NOEs and interesting three-spin
effects (
86JMR519-69
,
86JCS647
, and
88MRC852
)
can also be observed.
