A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced...

Area of Science:

• Solid-state chemistry
• Materials science
• Spectroscopy

Background:

• Para-crystalline materials lack long-range order, posing challenges for structure determination.
• Bioinspired light-harvesting compounds require precise structural information for function.

Purpose of the Study:

• To develop a hybrid method for de novo structure determination of para-crystalline materials.
• To elucidate the structure of a novel naphthalene diimide (NDI)-salphen-phenazine light-harvesting compound.

Main Methods:

• Hybrid magic-angle spinning (MAS) NMR spectroscopy and transmission electron microscopy (TEM).
• Analysis of low-resolution TEM diffraction data and reflection conditions.
• Refinement using heteronuclear distance constraints.

Main Results:

• Successful de novo structure determination, including space group assignment, for a para-crystalline material.
• Elucidation of the racemic P2/c packing symmetry and molecular arrangement.
• Determination of the orientation of lamellae on an electrode surface.

Conclusions:

• The hybrid MAS NMR-TEM approach overcomes limitations in determining structures of materials with limited order.
• The determined structure provides insights into the self-assembly and potential function of the NDI light-harvesting compound.