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Determination of Controlled Selfassembly of a Paracrystalline Material by Homology Modelling with Hybrid NMR and TEM.

Research paper by Brijith B Thomas, Jeroen J Rombouts, Karthick Babu Sai Sankar KBSS Gupta, Romano V A RVA Orru, Koop K Lammertsma, Huub J M HJM de Groot

Indexed on: 31 May '17Published on: 31 May '17Published in: Chemistry - A European Journal



Abstract

Controlling complexity, flexibility and functionality of synthetic and biomimetic materials requires insight into how molecular functionalities can be exploited for steering their packing. We show for a fused NDI-Salphen prototypic artificial photosynthesis material DATZnS comprising a phenazine motif that the alignment of electric dipole moments in a P2/c supramolecular scaffold can be modulated with bulky substituents and switched between parallel stacks of dipoles running antiparallel in the DATZnS-H compared with parallel stacks of dipoles in polar layers running in opposite directions in the DATZnS(3'-NMe) parent compound. Spatial correlations obtained from HETCOR spectra collected with a long cross polarization contact time of 2 ms reveal an antiparallel stacking for the DATZnS-H homologue. These constraints and limited data from TEM are used to construct a structural model within the P2/c space group determined by the molecular C2 symmetry. By homology modelling we find that pseudo octahedral coordination of the Zn follows the packing induced chirality with enantiomeric pairs of the Λ and ∆ forms alternating along antiparallel stacks. The model helps to understand how the steric hindrance modulates the selfassembly in this novel class of fused materials by steric hindrance at the molecular level.