Attractive interactions between an alkyne group and two carbonyl oxygen atoms: the crystal and molecular structure of 2,2′-ethynylenedibenzoic acid at 150 K

Abstract

The X-ray crystal structure of 8 shows two attractive intramolecular interactions between sp carbon atoms and adjacent carbonyl oxygen atoms, leading to a twisting of the triple bond equivalent to an orthogonal combination of cis and trans bends; the two carboxylic acid groups lie to the same side of the triple bond to avoid unfavourable contacts between carbonyl oxygen atoms and incipient carbanionic centres.