Bending by Faulting: A Multiple Scale Study of Copper and Silver Nitropyrazolates

A multiscale approach, combining
structural and microstructural
characterizations, was applied to tackle an uncommon and so far unsolved
structural problem occurring in group 11 nitropyrazolates. To this
goal, the average structure of the [Ag­(4-NO2-pz)]3 and [Cu­(4-NO2-pz)]3 species was determined
through ab initio X-ray powder diffraction techniques on high-resolution
synchrotron data, and used to infer molecular models of randomly distributed
defects within molecular stacks of trimeric molecules of D3h idealized symmetry. By cross-coupling
the size and shape information on nanocrystalline coherent domains
derived from tailored Debye function simulations with those obtained
from scanning electron miscroscopy images on multidomain particles,
the mechanism of structural disorder disrupting crystal periodicity
is proposed. Such a model was further supported through the derivation
of the pair distribution function, which affords local features to
be sought independently from the presence of structural periodicity.
Finally, the effects of stacking faults on the electrical properties
of [Ag­(4-NO2-pz)]3 have been experimentally
evaluated.