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Chemistry Forums for Students => Organic Chemistry Forum => Organic Spectroscopy => Topic started by: Misa on October 09, 2016, 08:37:08 AM

Title: Reasons for amorphous peak in NMR?
Post by: Misa on October 09, 2016, 08:37:08 AM
I have been working with compounds derived from 1,10-Phenanthroline. For products with different functional groups, solvents and reaction conditions, I am seeing an amorphous peak for the protons meta to the nitrogens instead of the expected dd.

What could be reasons for this distortion?

The compounds are known to π stack and I was wondering if that could be a factor?

Any ideas would be greatly appreciated !!  :D :D
Title: Re: Reasons for amorphous peak in NMR?
Post by: TheUnassuming on October 10, 2016, 08:59:56 AM
Are the other peaks in your spectra clean?  When you search the literature for similarly substituted compounds, do the spectra reported also show this muddy meta proton?
Title: Re: Reasons for amorphous peak in NMR?
Post by: Babcock_Hall on October 10, 2016, 05:34:25 PM
One might consider the possibility of a paramagnetic impurity.  However, the hydrogen atoms closest to the paramagnetic center should show the greatest broadening, all else held equal.
Title: Re: Reasons for amorphous peak in NMR?
Post by: Irlanur on October 19, 2016, 04:55:18 AM
can you post the spectrum/peak?