Electron crystallography on polymorphic organics

U. Kolb und G. N. Matveeva

Abstract

Organic materials, such as non-linear optical active compounds (1-(2-furyl)-3-(4-aminophenyl)-2-propene-1-one (FBAPPO) and 1-(2-furyl)-3-(4-benzamidophenyl)-2-propene-1-one (FAPPO)), polymeric materials like the metal coordinated polyelectrolyte (Fe(II) [ditopic bis-terpyridin] (MEPE)) or polymorphic materials (e.g. Cu-phthalocyanine), which do not crystallize big enough for single crystal x-ray structure analysis have been investigated by electron diffraction (ED) at 100 and 300 kV acceleration voltage. Sample preparation (direct crystallization, ultra sonication, ultra microtomy), diffraction strategies (selected area diffraction, nano diffraction, use of double-tilt rotation holder), data collection and data processing as well as structure solution strategies have been chosen dependent on the different requirements of the compounds under investigation. Structure analysis was carried out by simulation using ab initio quantum-mechanical methods like density functional theory (DFT), semi-empirical approach (MNDO/AM1/PM3) and force field packing energy calculations (DREIDING). The structure models resulting from simulation were refined kinematically as rigid bodies. Subsequently, refinements by multi-slice least squares (MSLS) procedures taking dynamical scattering into account were performed. The described combination of different methods which was used successfully on crystallizable materials is also adaptable to insoluble organic materials (e.g. pigments) and polymorphic systems.

Artikel kaufen
Erhalten sie sofort unbegrenzten Zugriff auf den Artikel.
Anmelden
Haben Sie den Zugang bereits erworben? Melden Sie sich bitte an.


oder
Zugriff über Ihre Institution

Zeitschrift + Hefte

Zeitschrift für Kristallographie – Crystalline Materials bietet ein Forum für Wissenschaftler, ihre kristallographischen Studien zu präsentieren. Die Zeitschrift beinhaltet sowohl theoretische als auch experimentelle Forschung. Publiziert werden Originalbeiträge, Letters und Übersichtsartikel auf dem gesamten Gebiet der Kristallographie.

Suche