Correlating Local Geometry to ¹¹B NMR Chemical Shifts of Tetrahedrally Coordinated Boron in Molecular Sieves

Creators: Park, Youngkyu; Koller, Hubert; Lew, Christopher M.; Zones, Stacey I.; Davis, Mark E.¹

1. California Institute of Technology

Abstract

The average B–O–T angles (B, O, and T denote boron, oxygen, and tetrahedrally coordinated atoms, respectively) are used as local geometric parameters for framework-incorporated B-sites within crystalline, borosilicate molecular sieves and are obtained from density-functional theory (DFT) calculations. The linear relationship between the B–O–T angles and the ¹¹B NMR chemical shifts reported previously for smaller angles in minerals is shown here to extend to the larger angles more typical within crystalline molecular sieves. In total, the correlation can be employed to investigate tetrahedrally coordinated B atoms for the entire class of three-dimensional, crystalline borosilicates.

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Acknowledgement

This research was financially supported by Chevron Energy Technology (grant no. CW789506). The authors thank Dr. Sonjong Hwang of the solid-state NMR facility at Caltech for the help with solid-state NMR experiments and for advice on data interpretation. The authors gratefully acknowledge Dr. Lynne B. McCusker of the Laboratory for Crystallography at ETH for providing the structure refinement data for B-sites within B-SSZ-82. Y.P. acknowledges the Kwanjeong Educational Foundation for financial support.

Contributions

Y.P. and M.E.D. designed the research. Y.P. performed experimental characterizations. H.K. conducted DFT calculations. C.M.L. and S.I.Z. prepared the samples. Y.P., H.K., S.I.Z., and M.E.D. analyzed the data. All authors wrote and revised the manuscript and have given approval to the final version of the manuscript.

Data Availability

Calculation method of ¹¹B NMR chemical shift, synthesis method, XPD plots, SEM images of borosilicate molecular sieves, calculated structure data of borosilicate minerals and molecular sieves, ¹H and¹¹B NMR spectra and¹¹B chemical shifts of borosilicate molecular sieves, and correlation plots (PDF)

Conflict of Interest

The authors declare no competing financial interest.

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