A Cambridge Structural Database analysis of the C–H⋯Cl interaction: C–H⋯Cl− and C–H⋯Cl–M often behave as hydrogen bonds but C–H⋯Cl–C is generally a van der Waals interaction

Abstract

A survey of organic crystal structures in the CSD for C–H⋯Cl contacts with Cl–M, Cl− and Cl–C acceptor moieties shows the inverse distance–angle correlation characteristic of a hydrogen bond for C–H⋯Cl–M and C–H⋯Cl− type interactions. The d–θ scatter plot for the C–H⋯Cl–C interaction has many points in the van der Waals region. Further, the H⋯Cl bond is shorter with activated donors for Cl–M and Cl− acceptors but not for Cl–C. These frequency data may be useful to classify C–H⋯Cl interactions as hydrogen bonds or van der Waals interactions in crystal structure analysis.