Crystal Structure and Thermal Phase Behaviour of 2,3‐Dicyano‐4‐n‐hexyloxyphenyl‐trans‐4‐n‐heptyleyelohexanoate

The title compound with the formula C 7 H 15 C 6 H 10 COOC 6 H 2 (CN) 2 OC 6 H 13 (DHPHC) crystallizes in the monoclinic space group P 21/n with a = 5.633(1), b = 14.254(1), c = 33.435(7) Å, β = 91.56(2)°, and four molecules per unit cell. The structure has been solved by direct methods and refined to R = 0.082. The DHPHC molecules adopt a banana‐shaped but considerably stretched form and show a parallel arrangement of their long axes in the crystal lattice. The phase transitions of DHPHC have been investigated by DSC and thermal microscopy. The compound shows a rather complicated melting behaviour and forms two solid phases and a monotropic smectic A phase.