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Greetings, this is my first question in this wiki :) I wonder if there's possibility to obtain full homo decoupled spectrum of 19F. Spectrum of my compound is quite complicated becouse of 19F-19F couplings. I have BBOF probe for Bruker Avance III HD spectrometer. 19F is tuned at broadband coil. If there's any possibility to make that, please give me some clues. Thanks, Arek EDIT I have obtained projection that looks like the one I need. Projection from 2D 19F J-res spectrum. I wonder if there's some kind of pureshift experiments designated for fluorine |
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Pure shift pulse sequences can be downloaded from the Manchester group web site. If you have a Zangger-Sterk pure shift experiment set up for 1H, then it's straightforward to convert it to 19F, just increase the gradient strength during the 180° pulse in direct proportion to the spectral width (i.e. if you use 0.1 G/cm for 1H with a sw of 5kHz and your 19F sw is 50 kHz, use a gradient of 1.0 G/cm). Sensitivity is proportional to 180° pulse bandwidth divided by gradient strength, so start with a fairly short selective pulse (5 ms or so) and only make it more selective if you need to decouple close resonances. Good luck! Gareth Morris |
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Thank you for answer. Today I'll try to check how it's going to work at perfluored alkanes. By the way, I must admit that all these pure shift experiments are great, it's like a next step to high resolution NMR, I don't know, maybe extreme resolution NMR ? |
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I've obtained 19F full homodecoupled spectrum. Thank you prof. Morris for this tutorial, it helps me a lot. Now I'm optimizing pushCTnQFCOSY sequence for my compounds. There's only four words that can describe it: it is a magic. I'm full of admiration to your invention. I'll use it and cite it in all of my papers. Thank you very much. Arkadiusz Leniak Institure of Organic Chemistry Polish Academy of Sciences This link shows how it works for 19F: http://1drv.ms/U1kHNm - Arkadiusz Leniak (Jun 16 '14 at 00:14) |
Pure shift full decoupled spectra for 1H works quite nice for me, now it's time for 19F. I hope it's gonna work. Probably calibration of gradients will take most of time needed for run this experiment :/ - Arkadiusz Leniak (Jun 06 '14 at 05:02)