title: A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced para-Crystalline Optical Materials.
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 C2molecular 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 C2symmetry 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.
authors.affiliation: Leiden Institute of Chemistry, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
authors.forename: Brijith
authors.initials: B
authors.lastname: Thomas
authors.affiliation: Vrije University Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Rombouts
authors.affiliation: Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
authors.forename: Gert T
authors.initials: GT
authors.lastname: Oostergetel
authors.affiliation: Leiden Institute of Chemistry, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
authors.forename: Karthick B S S
authors.initials: KB
authors.lastname: Gupta
authors.affiliation: Leiden Institute of Chemistry, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
authors.forename: Francesco
authors.initials: F
authors.lastname: Buda
authors.affiliation: Vrije University Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands.|Department of Chemistry, University of Johannesburg, Auckland Park, Johannesburg, 2006, South Africa.
authors.forename: Koop
authors.initials: K
authors.lastname: Lammertsma
authors.affiliation: Vrije University Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Romano
authors.initials: R
authors.lastname: Orru
authors.affiliation: Leiden Institute of Chemistry, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
authors.forename: Huub J M
authors.identifier: http://orcid.org/0000-0002-8796-1212
authors.initials: HJ
authors.lastname: de Groot
keywords: NMR spectroscopy; electron microscopy; magic-angle spinning; photochemistry; self-assembly