Crystal engineering with p-substituted 4-ethynylbenzenes using the C–H⋯O supramolecular synthon

The crystal structures of several para-substituted ethynylbenzene derivatives; namely, 4-ethynylanisole (1), 4-ethynylmethylbenzoate (2), 4-ethynylbenzaldehyde (3), 4-ethynyl-2,3,5,6-tetrafluoroanisole (4), 4-ethynylthioanisole (5), and 4-ethynyltoluene (6) have been solved from X-ray diffraction data. In 1–4, the molecular packing consists of infinite chains of molecules, linked by intermolecular C–H⋯O hydrogen bonds. The structure of 5 contains weak bifurcated C–H⋯S and C–H⋯π (CC) interactions and that of 6, C–H⋯π(benzene) interactions.