Crystal structure of disordered nanocrystalline α^II-quinacridone determined by electron diffraction

Abstract

The nanocrystalline αII-phase of the industrially produced organic pigment quinacridone was studied by 3D electron diffraction. The average crystal structure was obtained directly from the data and validated by energy minimization. A model describing the experimentally observed diffuse scattering was proposed.

Orientational disorder of monomethyl-quinacridone investigated by Rietveld refinement, structure refinement to the pair distribution function and lattice-energy minimizations

“…Materials with weakly bonded layers often show diffuse scattering associated with stacking faults of the layers, as was seen by ED of the II -phase of unsubstituted quinacridone (Gorelik et al, 2016). For MMQ, no diffuse scattering associated with such stacking faults was observed.…”

Rapid Structure Determination of Microcrystalline Molecular Compounds Using Electron Diffraction

“…[1][2][3][4] Thet hree-dimensional structure of am olecule is determined by the bonds between its atoms,w hich determine the moleculesf unction, reaction kinetics,a nd thermodynamics.I na ddition to the structure of am olecule, crystallisation as different polymorphs leads to different macroscopic properties:Different pigment polymorphs demonstrate different colour shades and fastness, [5,6] and the uptake of drugs improves or worsens depending on the polymorph. [1][2][3][4] Thet hree-dimensional structure of am olecule is determined by the bonds between its atoms,w hich determine the moleculesf unction, reaction kinetics,a nd thermodynamics.I na ddition to the structure of am olecule, crystallisation as different polymorphs leads to different macroscopic properties:Different pigment polymorphs demonstrate different colour shades and fastness, [5,6] and the uptake of drugs improves or worsens depending on the polymorph.…”

“…Crystallography is an essential technology in most fields of chemistry. [1][2][3][4] Thet hree-dimensional structure of am olecule is determined by the bonds between its atoms,w hich determine the moleculesf unction, reaction kinetics,a nd thermodynamics.I na ddition to the structure of am olecule, crystallisation as different polymorphs leads to different macroscopic properties:Different pigment polymorphs demonstrate different colour shades and fastness, [5,6] and the uptake of drugs improves or worsens depending on the polymorph. Therefore,d ifferent patents are granted for different polymorphs of the same compound.…”

Schnelle Strukturaufklärung mikrokristalliner molekularer Verbindungen durch Elektronenbeugung

“…[1][2][3][4] Die dreidimensionale Struktur eines Moleküls ist durch die Bindungen zwischen seinen Atomen festgelegt, welche die Funktion des Moleküls, dessen Reaktionskinetik und Thermodynamik bestimmen. Neben dieser Molekülstruktur führen unterschiedliche Kristallpackungen (Polymorphe) zu unterschiedlichen makro-skopischen Eigenschaften:B ei Pigmentstoffen führt Polymorphie zu unterschiedlichen Farbtçnen und unterschiedlicher Farbechtheit, [5,6] und die Aufnahme von Medikamenten wird in Abhängigkeit von deren Polymorphen verbessert oder verschlechtert. Deswegen kçnnen verschiedene Polymorphe desselben Wirkstoffes einzeln patentiert werden.…”