Determination of Controlled Self-Assembly of a Paracrystalline Material by Homology Modelling with Hybrid NMR and TEM.

ABSTRACT: Controlling complexity, flexibility, and functionality of synthetic and biomimetic materials requires insight into how molecular functionalities can be exploited for steering their packing. A fused NDI-salphen (NDI=naphthalene diimide) prototypic artificial photosynthesis material, DATZnS, is shown to be comprised of a phenazine motif, in which the alignment of electric dipole moments in a P2/c supramolecular scaffold can be modulated with bulky substituents. They can also be 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 using homology modelling, a pseudo octahedral coordination of the Zn is shown to follow the packing-induced chirality with enantiomeric pairs of the ? and ? forms alternating along antiparallel stacks. The model helps to understand how the steric hindrance modulates the self-assembly in this novel class of fused materials by steric hindrance at the molecular level.

SUBMITTER: Thomas B 

PROVIDER: S-EPMC5519927 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature