α,β-Unsaturated Ketoximes Carrying a Terminal Pyridine or Quinoline Subunit as Building Blocks for Supramolecular Syntheses

The crystal structures of a new series of α,β-unsaturated ketoximes, 8−14, carrying the terminal 4-pyridinyl, 3-pyridinyl, or 4-quinolinyl subunit have been investigated by X-ray structural analysis. The dominating intermolecular interaction in all structures, except 11, is the head−tail OH···N hydrogen bond between the oxime moiety and the nitrogen atom of the heterocyclic unit. This intermolecular interaction generates infinite chains, which are cross-linked by CH···O/N/Cl or CH···π interactions. Compound 10 has been shown to adopt a double-helical structure in the crystalline state. Compound 11 represents the only case where the unexpected head−head NOH···N(OH) hydrogen bonds determine the crystal packing. Both hydrogen-bonding and aromatic interactions stabilize the crystal structures of 8−14.