Mag. Reson. Chem. 56, 1083-1088 (2018)

DOI: 10.1002/mrc.4754

Libration of phenyl groups detected by VT‐SSNMR:Comparison with X‐ray crystallography

The X‐ray crystal structure of 2‐benzyl‐1H‐benzimidazole, 2BnBzIm, was determined at 293 K showing no dynamic phenomena (disorder) of any class. On the other hand, some 13C NMR signals were absent in the CPMAS spectrum (100 MHz, 300 K). We decided to carry out variable‐temperature SSNMR and discovered that the missing signals are orthoand meta carbons of the phenyl ring of the benzyl group. Line‐shape analysis and the Eyring equation were used to determine the barrier, which was compared with the calculated DFT for the gas phase that it is much lower.