A structural analysis of 2,5-diaryl-4H-2,4-dihydro-3H-1,2,4-triazol-3-ones: NMR in the solid state, X-ray crystallography, and GIPAW calculations.

The 1 H, 13 C, 15 N, and 19 F nuclear magnetic resonance (NMR) spectra of 11 2,5-diaryl-2,4-dihydro-3H-1,2,4-triazol-3-ones have been acquired in DMSO-d6 solution and the 13 C, 15 N, and 19 F NMR spectra have also been acquired in the solid state (solid-state nuclear magnetic resonance [SSNMR] and magic angle spinning [MAS]). The X-ray structures of Compounds 3, 5, and 6 have been determined by X-ray diffraction. Theoretical calculations at the gauge-independent atomic orbital (GIAO)/B3LYP/6-311++G(d,p) level have provided a set of 321 chemical shifts that were compared with 310 experimental values in DMSO-d6 . To obtain good agreements, some effects need to be included. The SSNMR chemical shifts have been compared with gauge-including projector-augmented wave (GIPAW) calculations and with the heavy atom-light atom (HALA) effects.