Abstract
Hybrid magic-angle spinning (MAS) NMR spectroscopy and TEM were demonstrated for de novo structure determination of para-crystalline materials with a bioinspired fused naphthalene diimide (NDI)–salphen–phenazine prototype light-harvesting compound. Starting from chiral building blocks with C2 molecular symmetry, the asymmetric unit was determined by MAS NMR spectroscopy, index low-resolution TEM diffraction data, and resolve reflection conditions, and for the first time the ability to determine the space group from reciprocal space data using this hybrid approach was shown. Transfer of molecular C2 symmetry into P2/c packing symmetry provided a connection across length scales to overcome both lack of long-range order and missing diffraction-phase information. Refinement with heteronuclear distance constraints confirmed the racemic P2/c packing that was scaffolded by molecular recognition of salphen zinc in a pseudo-octahedral environment with bromide and with alkyl chains folding along the phenazine. The NDI light-harvesting stacks ran orthogonal to the intermolecular electric dipole moment present in the solid. Finally, the orientation of flexible lamellae on an electrode surface was determined.
Original language | English |
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Pages (from-to) | 3280-3284 |
Number of pages | 5 |
Journal | Chemistry - A European Journal |
Volume | 23 |
Issue number | 14 |
DOIs | |
Publication status | Published - 8 Mar 2017 |
Funding
This work is part of the research program of the NWO uNMR distributed large scale facility and was supported by the Biosolar cells project of the Dutch Ministry of Economic Affairs, Agriculture and Innovation. The microscopy was performed in the NECEN cryo-EM facility in Leiden.
Funders | Funder number |
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Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
Ministerie van Economische Zaken, Landbouw en Innovatie |
Keywords
- electron microscopy
- magic-angle spinning
- NMR spectroscopy
- photochemistry
- self-assembly