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-NO 2-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.
Bending by faulting: A multiple scale study of copper and silver nitropyrazolates
MASPERO, ANGELO;MASCIOCCHI, NORBERTO;BERTOLOTTI, FEDERICA
2014-01-01
Abstract
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-NO 2-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.
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