A Solid-State NMR Method for Solution of Zeolite Crystal Structures

• Published in: Journal of the American Chemical Society Vol. 127; no. 29; pp. 10365 - 10370
• Main Authors: Brouwer, Darren H, Darton, Richard J, Morris, Russell E, Levitt, Malcolm H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 27.07.2005
• Subjects: Chemical and knight shifts; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Magnetic resonance techniques; mössbauer spectroscopy; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Nuclear magnetic resonance and relaxation; Other methods of structure determination; Physics; Structure of solids and liquids; crystallography; Inorganic compounds; Crystal orientation; Aluminosilicates; Homonuclear correlation; Experimental study; Molecular sieves; Zeolites; Solid state; Silicon 29; Two-dimensional spectroscopy; Crystal morphology; NMR spectroscopy; Crystal structure; Pulse sequence
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja052306h

Since zeolites are notoriously difficult to prepare as large single crystals, structure determination usually relies on powder X-ray diffraction (XRD). However, structure solution (i.e., deriving an initial structural model) directly from powder XRD data is often very difficult due to the diffraction phase problem and the high degree of overlap between the individual reflections, particularly for materials with the structural complexity of most zeolites. Here, we report a method for structure determination of zeolite crystal structures that combines powder XRD and nuclear magnetic resonance (NMR) spectroscopy in which the crucial step of structure solution is achieved using solid-state 29Si double-quantum dipolar recoupling NMR, which probes the distance-dependent dipolar interactions between naturally abundant 29Si nuclei in the zeolite framework. For two purely siliceous zeolite blind test samples, we demonstrate that the NMR data can be combined with the unit cell parameters and space group to solve structural models that refine successfully against the powder XRD data.