Dear Gerwald, dear Artem,
As, in the absence of quantum mechanical calculations, we can only
speculate about the contribution of mesomeric states it seems to me
from the data presented that the left formula (i.e. without the
mesomeric effect) may match the structural situation, in particular
Take one crystal and put it in mother liquor.
Increase gradually (in two separately experiments) your ethanol and DMSO
concentration (in my experience it could go up to 10%v/v after 1 week for
some crystals) in order to find out the concentration that your crystal can
stand without dissolve or crac
