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What is COSY and HSQC?

What is COSY and HSQC?

Dear Hicham, COSY is a 2D spectrum that shows scalar coupling between vicinal H atoms (via 3 bonds). On both axis you have 1H spectrum and you can see the exact correlations and it can help you resolve structure. HSQC on the other hand shows correlation between C and H that is bonded to it (via 1 bond).

What is HSQC NMR?

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.

How do you interpret a COSY NMR?

¹H-¹H Correlation Spectroscopy (COSY) shows the correlation between hydrogens which are coupled to each other in the ¹H NMR spectrum. The ¹H spectrum is plotted on both 2D axes….Step 2: ¹H-¹H COSY.

Chemical Shift (ppm) COSY correlations Assignment
1.770 3-4 3

How does HSQC work?

HSQC works by transferring magnetization from the I nucleus (usually the proton) to the S nucleus (usually the heteroatom) using the INEPT pulse sequence; this first step is done because the proton has a greater equilibrium magnetization and thus this step creates a stronger signal.

How long does an HSQC take?

The HSQC experiment is a highly sensitive 2D-NMR experiment and was first described in a 1H—15N system, but is also applicable to other nuclei such as 1H—13C and 1H—31P.

What is the difference between COSY and Noesy?

For example, the presence of a cross peak (a correlation off the diagonal) on a COSY dataset is a result of nuclei coupling through a bond(s) whereas a NOESY dataset measures NOE’s (Nuclear Overhauser Effect) through space regardless of the number of bonds separating the nuclei.

What is COSY technique?

COSY is a technique for determining correlations through the chemical bond. In it’s most used form this allows us to see which proton resonances are mutually coupled. As described in the section on 1H spectra, coupling of protons through 2,3 or 4 bonds has a significant impact on the appearance of a proton spectrum.

Is HSQC phase sensitive?

The HSQC spectrum that you have just run is phase sensitive. You must phase it. An out-of-phase spectrum will look strange and will show dramatic intensity differences on either side of all peaks.

What is the HSQC NMR experiment?

Gained Information: The H eteronuclear S ingle Q uantum C orrelation (HSQC) NMR experiment is a proton-detected 2D experiment that shows you 1H / 13C one-bond connectivity. You will see your 1H spectrum as your direct F2 axis and your 13C spectrum as your indirect F1 axis.

What is a COSY NMR experiment?

Gained Information: The COrrelation SpectroscopY (COSY) NMR experiment is a proton-detected 2D experiment that shows you protons that are J-coupled. You will see your 1H spectrum on both axis, and you will see a cross peak for any protons that are J-coupled.

What is HSQC and HMBC in chemistry?

HSQC and HMBC. 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.

What is HSQC spectroscopy?

HSQC Spectra of Other Nuclear Pairs •  HSQC (and HMQC, see later) are used to correlate many types of nuclei – for biomolecular NMR, mostly 1H-15N, 1H-13C, 1H-31P, etc. – example below: 13C-103Rh Preparation Period for HSQC Experiment •  The INEPT sequence serves as the ‘preparation’ period for the HSQC experiment (and many other experiments)