COSY spectra show 3-bond coupling (from H-C-C-H), whereas HMQC shows a 1-bond coupling (just C-H). Take a look at n-hexylbenzene. There are lots of similar positions in this structure, so it may be hard to tell peaks apart in either the proton or carbon NMR spectrum.

Like HMQC, the HSQC experiment is a 2D heteronuclear chemical shift correlation map between directly-bonded (J -coupled) 1 H and X-heteronuclei (such as 13 C and 15 N). HSQC techniques are frequently used in structure elucidation of organic molecules, as well as in protein NMR spectroscopy (Bodenhausen, and Ruben, 1980).

The HSQC (Heteronuclear Single Quantum Coherence) experiment is used to determine proton-carbon single bond correlations, where the protons lie along the observed F2 (X) axis and the carbons are along the F1 (Y) axis. An edited HSQC spectrum of …

HSQC(heteronuclear singular quantum correlation, 异核单量子关系)：隶属于NMR（核磁共振）C-H COSY 谱图中的一种，HSQC给出的信息与HMQC一样，都是直接相连的碳氢关系1JC-H，而不能解决碳与季碳相连的问题，或隔碳相连的问题。

HMQC, which is based on multiple-quantum NMR, minimizes this dynamic range problem while optimizing the sensitivity of the experiment. The resonance frequency of low γ spins can be detected with enhanced sensitivity by the creation and 1 H detection of 1 H 13 C (or other X nucleus) multiple-quantum coherence.

2009年1月14日 · Proton detected Heteronuclear Multiple Quantum Coherence (HMQC) and Heteronuclear Single Quantum Coherence (HSQC) are both NMR techniques used to correlate the chemical shift of the protons in a sample to a heteronucleus such as 13 C or 15 N via the J coupling interaction between the nuclei. Since both techniques essentially provide the same ...

2024年11月12日 · Heteronuclear Correlations: HMQC* One Bond Heteronuclear Correlations. Heteronuclear Multiple Quantum Coherence (and HSQC and Het-Cor) detect correlations between nuclei of two different types that are separated by one bond. This method gives one peak per each coupled pair. This technique is often used to …

Gradient Selected Phase-sensitive HMQC Differences between HSQC and HMQC. Similiar to 1H-13C HSQC, HMQC reveals through-bond correlations between 1H and one-bond connected heteronucleus such as 13C.

2004年1月12日 · The basic building blocks of the multitude of double and triple resonance experiments available today are the heteronuclear multiple quantum correlation (HMQC) and heteronuclear single quantum correlation (HSQC) experiments.

その手法のひとつに、HMQC（Heteronuclear Multiple Quantum Correlation）と呼ばれる2次元NMR測定手法があります。このHMQCスペクトルにより、直接結合している水素と炭素を調べることができます。