Characterisation of weak intramolecular interactions in the topology of the experimental charge density of 2,2 '-ethynylenedibenzoic acid

A multipole model of the charge density distribution in the di-substituted alkyne title compound containing weak intramolecular interactions as define d by the topology of the charge density, has been obtained from high-resolu tion single crystal diffraction data. Bond paths are located between formal ly non-bonded C and O atom pairs and also between a pair of O atoms. This o bservation of weak intramolecular interactions in an experimentally derived charge density proves that the multipole modeling formalism is sufficientl y sensitive to detect such features which are small on an absolute scale. E vidence is presented which suggests that the cis conformation of the molecu le in this particular crystalline state is due to strong intermolecular hyd rogen bonding.