Dear All
We have been trying some indirect detection experiments for some of our molecules and we not getting good results, particularly for gradient HMBC Experiments. The following are the main difficulties:
· What parameters are to be used to get contours with proper intensities representing three and two bond couplings? How to get intense contours for three bond connectivity's and less intense contours for two bond connectivity's ? Of course in some case the intensities of the contours for both these connectivity's will be same and we confirm the connectivity's checking with other bonded atoms.
· Why sometimes three bond couplings are not seen at all and as I have observed with carbonyl carbons such discrepancies are very often?. What to do under such circumstances? What parameter to vary and how to get it resolved? It would be great favour if you can tell me the relation between the parameters and the couplings.
· I have come across with some papers wherein they are using the protons bonded to hetero atoms like O, N, to see the three bond and two bond couplings in HMBC. Will you please send me some information on this? This will help me to solve some of the crucial problems with our compounds.
I do understand that I am asking for a lot of material and it would take quite some of your valuable time. Please bear with me and help me out with these things since that will be of great use.
Thank you very much in anticipation.
Please suggest!
Regards
K. Muralidharan
Received on Mon Feb 20 2006 - 18:45:14 MST