[Misa]

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 !! 

[TheUnassuming]

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?

[Babcock_Hall]

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.

[Irlanur]

can you post the spectrum/peak?