1,5-Diaryl(heteroaryl)pentenynones show a tendency to crystallize in acentric space groups due to their inclination to form C-H...O hydrogen-bonded chains instead of dimers and thus exhibit nonlinear optical properties. A series of symmetrical α,α'-bis(3-arylprop-2-yn-1-ylidene)cycloalkanones and unsymmetrical α-(furan-2-ylmethylene)-α'-(3-arylprop-2-yn-1-ylidene)cyclohexanones closely related to pentenynones was synthesized, namely 2,5-bis(3-phenylprop-2-yn-1-ylidene)cyclopentanone, C23H16O, 2,5-bis[3-(4-bromophenyl)prop-2-yn-1-ylidene]cyclopentanone, C23H14Br2O, 2,6-bis(3-phenylprop-2-yn-1-ylidene)cyclohexanone, C24H18O, 2,6-bis[3-(4-bromophenyl)prop-2-yn-1-ylidene]cyclohexanone, C24H16Br2O, 4-tert-butyl-2,6-bis(3-phenylprop-2-yn-1-ylidene)cyclohexanone, C28H25O, 4-tert-butyl-2,6-bis[3-(4-methylphenyl)prop-2-yn-1-ylidene]cyclohexanone, C30H30O, 2-(furan-2-ylmethylene)-6-(3-phenylprop-2-yn-1-ylidene)cyclohexanone, C20H16O2, and 6-(3-butylprop-2-yn-1-ylidene)-2-(furan-2-ylmethylene)cyclohexanone, C10H20O2, and investigated by means of X-ray diffraction to understand peculiarities of their supramolecular organization. Four of the eight novel compounds crystallize in acentric space groups. Three of these four compounds contain substituents at the para position of the phenyl ring, which affect the charge density on the H(CPh) atoms and thus stabilize CPh-H...O interactions. The fourth compound realizes the C-H...O hydrogen bonding via H atoms of the furyl ring. The applicability and shortcomings of the Full Interaction Map tool to predict the likelihood of C-H...O and C-H...Br hydrogen-bonded motifs, and the effect of substituents on the phenyl ring on the supramolecular architecture are discussed.
Keywords: crystal structure; cyclic ketones; cyclohexanone; full interaction map; supramolecular organization; vinylacetylene fragments.