Ab-initio single crystal structure solution of dihydrodibenzoazepines

IND-PO-23 Ab-initio single crystal structure solution of dihydrodibenzoazepines X-ray diffraction represents the most direct non-invasive technique to investigate the structure of crystalline material in terms of atom positions in the crystalline cell. The availability of a single crystal of appropriate size and quality is required. X-ray diffraction is based on constructive interference occurring when Bragg’s Law (2d sinθ=nλ) is satisfied. Crystal structure solution needs to know the structure factor moduli and their phases. Unfortunately the diffraction experiment provides the moduli and not the phases. Therefore, the phase problem must be solved in order to find the unique set of phases that, combined with moduli, permits to calculate the electron density map from which an approximate structure model is derived. In a final step a reliable model may be carried out by structure refinement. Direct Methods (DM) are able to estimate the phases and solving abinitio crystal structures. In this work, the structure determination process of two dihydrodibenzoazepines (Figure 1) is performed by means the software Sir2011[1]. This is an automatic program supported by a very user friendly graphic interface. Several new algorithms have been implemented in Sir2011, making the program very efficient: it is able to solve both small/medium-sized structures as well as macromolecules. Details about synthesis and theoretical calculations of these molecules can be found in a companion paper [2]. [1] Burla, M.C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G., Giacovazzo, C., Mazzone, A., Polidori, G. & Spagna, R. (2011) – Advances in crystal structure solution: Sir2011 - J. Appl. Cryst., in preparation. [2] M. Catellani, N. Della Ca’, E. Motti, B.M. Aresta, C. Cuocci, S. Maggi, G. Maestri, E. Derat, M.Malacria , this Conference.