Looking for good explanatory notes to understand HMBC. Simple explanation with worked problem is also much appreciated.
You can try out these resources linked below.
Regards,
Rudy
http://homepages.strath.ac.uk/~bas01125/NMR_Teaching_Material/Postgraduate%20Course.htm
http://www-keeler.ch.cam.ac.uk/lectures/Irvine/
Hi,
I must ask you two questions, because I don't know in which aspects of HMBC, you are interested in.
1) Do you want to understand the pulse sequence, magnetization transfers and coherence pathways in HMBC?
2) Or maybe you are interested in practical aspects of obtaining and interpreting spectra?
Regards,
Arek
You can try out these resources linked below.
Regards,
Rudy
http://homepages.strath.ac.uk/~bas01125/NMR_Teaching_Material/Postgraduate%20Course.htm
http://www-keeler.ch.cam.ac.uk/lectures/Irvine/
You can try with this book:
Spectrometric Identification of Organic Compounds
Robert M. Silverstein, Francis X. Webster, David Kiemle, David L. Bryce
Hi Balaji,
If you would to understand the fundamental concept and basics for HMBC, you should browse the following links with supportive examples. I assume that you have to differentiate between two structures on orientation, for instance, or to have interpretation to your spectra analysis.
http://en.wikipedia.org/wiki/Two-dimensional_nuclear_magnetic_resonance_spectroscopy#Heteronuclear_multiple-bond_correlation_spectroscopy_.28HMBC.29
http://chem.ch.huji.ac.il/nmr/techniques/2d/hmbc/hmbc.html
I started with the simplest definitions then transfer to literature on HMBC.
@ G. Balaji you shoud look at this books:
High-Resolution NMR Techniques in Organic Chemistry
Tetrahedron Organic Chemistry Series
Volume 27, Pages 1-383 (2009) ; Timothy D.W. Claridge
NMR Spectroscopy Explained: Simplified Theory, Applications and Examples for Organic Chemistry and Structural Biology
Neil E. Jacobsen
Understanding NMR Spectroscopy
James Keeler
I think you will find there answers for you questions.
Best regards,
A. Leniak
HMBC provides the long range coupling of C and H. Using the correlations observed in the HMBC spectrum, easy to confirm the structure and connectivity
Dear Bala ji,
AS par Priyani Paranagama madam mentioned HMBC always give long rang coupling of C and H( 1H-3C relation) means if in your HMBC spectra dots are very prominent or dark then make line H-protion axis exact matching C- carbon axis if they matching accurately it means your 1Hproton connected with 3C position your carbon(1H-2C-3C).(1H-2C you can get by HSQC)
Hope it will work!!
The interaction between 1H and 13C, in terms of NMR coupling terminology and/or topology, is defined by nJCH where n can be 1, 2 and/or 3. While 1JCH is known to reveal direct correlation, 2JCH and 3JCH are known to reveal long range correlation. They are also known as one-bond and multiple-bond correlations respectively. While HSQC experiment reveals 1JCH, HMBC experiment reveals 2JCH and/or 3JCH. While the magnitude of 1JCH is in the range of ~120 Hz to ~170 Hz, 2JCH and 3JCH are in the range of ~4 to ~14 Hz.If one expects to have the range of 2JCH and 3JCH then, the HMBC experiment has to be performed for different values, say 6 Hz, 8 Hz, 10 Hz and 12Hz.
The interpretation can well be accomplished if one records both HSQC and HMBC experiments and compare the results.
Last but not least, one point has to be remembered. A typical JHH value can match 2JCH and 3JCH values. So, one has to be careful while interpreting a HMBC result.
My recommendation is to record HSQC and HMBC on a small molecule such as ethylbenzene (which is usually supplied as a reference standard along with an NMR spectrometer system by the respective vendor) and start analyzing the results.
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