Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites
<sup>14</sup>N magic-angle spinning (MAS) NMR spectra of diamagnetic LaTiO<sub>2</sub>N perovskite oxynitride and its paramag-<br>netic counterpart CeTiO<sub>2</sub>N are presented. The latter, to the<br>best of our knowledge, constitutes the first high-resolution <sup>14</sup>N MAS NMR spectrum collected from paramagnetic solid material. Induced paramagnetic <sup>14</sup>N NMR shift due to unpaired 4<i>f</i> -electrons in CeTiO<sub>2</sub>N is non-existent, which is remarkable given the severe paramagnetic effects on surface proton species revealed by <sup>1</sup>H NMR, and direct Ce−N contacts in the structure. <i>Ab initio</i> molecular orbital calculations predict substantial Ce→<sup>14</sup>N contact shift interaction under these circumstances, therefore, cannot explain the unprecedented <sup>14</sup>N NMR spectrum of CeTiO<sub>2</sub>N.