Crystal and Molecular Structure of 4(3-Acryloyloxy)octyloxy-and 4(3-Acryloyloxy)hexyloxy-4'-cyanobiphenyls

摘要

The molecular and crystal structures of N=C-C_6H_4-C_6H_4-O-(CH_2)_8-O-CO-CH=CH_2 (4(3-acryloyloxy)octyloxy-4'-cyanobiphenyl) (I) and N=C-C_6H_4-C_6H_4-O-(CH_2)_6-O-CO-CH=CH_2 (4(3-acryloyloxy)hexyloxy-4'-cyanobiphenyl) (II) were determined by X-ray diffraction. The structures of I and II are stereotype. The space group of I and II is C2/c, Z= 8; lattice parameters I: a = 34.677(7) A,b = 9.452(2) A, c= 13.004(3) A, β = 99.30(3)°; II: a = 30.858(6) A, b = 9.504(2) A, c = 13.082(2) A, β = 92.78(3)°. The planar extended molecules I and II are packed in the unit cell to give clearly differentiated aliphatic and aromatic regions throughout the whole crystal. All intermolecular contacts are concentrated in the aromatic region. The molecular packing is very loose but the aromatic areas of I and II fully coincide. The only free parameter of the structure is the length of the aliphatic chain (CH_2)_n (n = 8 and 6). According to DSC data, compound I possesses enantiotropic mesomorphism and II possesses monotropic mesomorphism.