Unusual Through-Space, TS, Pathway for the Transmission of JFHf Coupling: 2‑Fluorobenzaldehyde Study Case

Abstract

The 1 H NMR spectra of the title compound in nonpolar and polar solvents and theoretical calculation of spin−spin coupling constants (SSCCs) show that TSJFHf SSCC, where TS stands for “through-space”, in polar solvents is amenable to measurement only in the trans conformer. The mechanisms for transmission pathways to such unusual SSCCs are rationalized in terms of the molecular electronic structure. It is stressed that such a result calls for some caution when intending to use TSJFH as a probe to detect the spatial proximity between fluorine and hydrogen atoms.