The influence of CH … π interaction on coupling constants across N … H–F hydrogen bond in a substituted T-shaped configuration: a theoretical study

For studying the influence of CH … π interaction on coupling constants across N … H–F hydrogen bond in a substituted T-shaped configuration, X-benzene⊥(FH … pyrazine … HF) complexes are chosen as a working model. NMR calculations are performed at B3LYP/6-311++G(d,p) and PBE0/6-311++G(d,p) levels. Here, correlations between energetic, geometrical and topological parameters and coupling constants are investigated. The results indicate that direct correlations exist between strength of N … H hydrogen bond, electron-donating power of substituents and |^2hJ_N−F|. Also, |^2hJ_N−F| increases as cooperative and synergistic energies become more negative. These behaviours are reversed for ^1hJ_N−H. Due to contradictory behaviours of FC and PSO terms, an irregular trend is observed for ¹J_H−F.