The CN⋯C–X σ-hole interaction acts as a conformational lock

Abstract

An interesting CN⋯C–X conformation lock, which determines the linear alignment of the CN and C–X fragments, has been found for the first time and is rationalized by density functional theory calculations. Second-order perturbation theory analysis based on the NBO method further reveals that the nature of the CN⋯C–X interaction is mainly the lp(CN) → σ*(C–X) interaction.