Wednesday, June 10, 2009

J. Am. Chem. Soc., 2009, 131 (23), pp 8271–8279

Application of Solid-State 209Bi NMR to the Structural Characterization of Bismuth-Containing Materials

Hiyam Hamaed†, Michael W. Laschuk†, Victor V. Terskikh‡ and Robert W. Schurko*†

Herein, we report the first detailed study of 209Bi solid-state NMR (SSNMR) spectroscopy of extremely broad central transition powder patterns. 209Bi ultrawideline SSNMR spectra of several bismuth-containing materials (bismuth oxyhalides, bismuth nitrate pentahydrate, nonaaquabismuth triflate, and bismuth acetate) were acquired at field strengths of 9.4 and 21.1 T using frequency-stepped techniques. The 209Bi SSNMR experiments at 9.4 T yield powder patterns with breadths ranging from 0.9 to 14.6 MHz, from which quadrupolar coupling constants, CQ(209Bi), between 78 and 256 MHz, were extracted via analytical simulations. The breadths of the quadrupolar-dominated spectra and overall experimental times are greatly reduced for experiments conducted at 21.1 T, which yield high signal-to-noise spectra in which the smaller effects of bismuth chemical shift anisotropy can be clearly observed. The 209Bi electric field gradient (EFG) and chemical shift (CS) tensor parameters extracted from these spectra are correlated to the molecular structures at the bismuth sites, via first principles calculations of 209Bi EFG and CS tensors performed using CASTEP for periodic solids and Gaussian 03 for molecular clusters. The rapidity with which 209Bi SSNMR spectra can be acquired at ultrahigh fields, the sensitivity of the 209Bi NMR parameters to the bismuth environment, and the predictive power of theoretically calculated NMR interaction tensors suggest that 209Bi SSNMR may be useful for the characterization of a variety of Bi-containing materials and compounds.

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