Wednesday 23 September 2015

10 MOST INTERESTING ACRONYMS IN NMR



Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most powerful analytical tools used for various purposes in scientific research. Chemists are the largest group of users of NMR, employed mainly for structure elucidation of unknown compounds. Several different types of techniques (each differing from the other by the pulse sequence involved) are used in NMR, affording different information about the structure of a compound. NMR has some of the most comprehensive terminologies used for its techniques. The acronyms used are even more interesting.
Following is a list of the acronyms of 10 different techniques used in NMR. Rest assured you will enjoy the ride.

1.    COSY
The acronym is used for “COrrelation SpectroscopY”, which is a two dimensional NMR technique, employed for the detection of scalar (through bonds) couplings between protons geminal or vicinal to each other.

2.    NOESY
Do not poke in your “nosey”, because NOESY stands for “Nuclear Overhauser Enhancement SpectroscopY”, a two dimensional NMR technique frequently used for determining the stereochemistry at different centers in a compound. NOESY is based on dipolar (through space) couplings.

3.    ROESY
ROESY is not the name of any girl, but an NMR acronym used for “Rotating-frame Overhauser Enhancement SpectroscopY”. The technique is slightly different from NOESY, but affords the same information (stereochemistry) about a compound.

4.    INADEQUATE
Please do not feel “inadequate” when you are using INADEQUATE, a powerful NMR technique used for determining the carbon framework within the molecule. The abbreviation stands for “Incredible Natural Abundance DoublE QUAntum Transfer Experiment”.

5.    DOSY
Diffusion Ordered SpectroscopY (DOSY) is a two dimensional NMR technique used for a mixture of compounds. The technique can effectively differentiate between signals from each compound.

6.    HOHAHA
Well, this not something for scaring you. HOHAHA means “HOmonuclear HArtmann HAhn”, also known as TOCSY (TOtal Correlation SpectroscopY). This technique can be considered as a long range COSY, as it can correlate all protons in a spin system (a network of carbon atoms bearing hydrogens).

7.    SECSY
SECSY is in no way related to being “sexy”. Spin Echo Correlation SpectroscopY (SECSY) makes use of the 2D J-resolved spectrum in NMR for structure determination of compound.

8.    STD
Sexually Transmitted Diseases (STD) are unquestionably a concern as far as the medical science is concerned. But what helps the medical science ascertain the cause of a health disorder or in identifying drug candidates is the STD (Saturation Transfer Difference) NMR technique. STD-NMR can effectively recognize the interaction of the active site of an enzyme with any molecule (epitope mapping).  

9.    DEPT
No need to go in “Depth”, DEPT is just an NMR technique, known as “Distortionless Enhancement by Polarization Transfer”. DEPT experiments are used for the identification of different types (methyl, methylene, methine, quaternary) of carbons in a molecule.

10.  dd
You must have heard about “Dee Dee”, Dexter’s sister. If not, ask somebody. In NMR, “dd” is just a splitting pattern called “double doublet” or “doublet of a double”. This pattern is observed for a proton having two chemically and magnetically inequivalent protons in its vicinity.

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