HOMCOR
Definition and meaning of HOMCOR in chemistry.
HOMCOR is a general term for homonuclear correlation spectroscopy, a family of two-dimensional NMR experiments that reveal couplings between nuclei of the same isotope within a molecule.
In more detail
In the classic solution-state case, a HOMCOR experiment such as COSY uses a simple pulse sequence (90 degree pulse, evolution delay t1, second 90 degree pulse, detection t2) so that magnetization transferred through scalar (J) coupling produces off-diagonal cross peaks in the resulting 2D spectrum. Each cross peak links two chemically distinct but coupled nuclei, letting chemists trace bonding connectivity through a molecule even when 1D spectra are too crowded to interpret directly. The concept has also been extended to solid-state NMR, where specialized HOMCOR pulse sequences (such as DQ-filtered or D-HOMCOR experiments) probe dipolar couplings between half-integer quadrupolar nuclei, which are more difficult to correlate than ordinary spin-1/2 nuclei.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Full meaning | HOMonuclear CORrelation spectroscopy |
| Technique type | Two-dimensional (2D) NMR experiment |
| Common example | 1H-1H COSY |
In a 1H-1H COSY spectrum (the most common HOMCOR experiment) of ethanol, a cross peak connects the CH2 and CH3 proton signals, confirming that these two groups are spin-coupled and therefore bonded to adjacent carbons.
Frequently asked questions
How does HOMCOR differ from HETCOR?
HOMCOR correlates nuclei of the same isotope, such as 1H with 1H, while heteronuclear correlation (HETCOR) correlates nuclei of different isotopes, such as 1H with 13C.
Is HOMCOR just another name for COSY?
COSY is the standard HOMCOR experiment for spin-1/2 nuclei like 1H, but HOMCOR is the broader umbrella term that also includes specialized homonuclear correlation sequences developed for quadrupolar nuclei in solid-state NMR.