1,4-Bis(hexyloxy)-2,5-diiodobenzene

The centrosym. title compd., C18H28I2O2, crystd. in the monoclinic space group P21/c with the alkyl chains having extended all-trans conformations, similar to those in the centrosym. bromo analog that crystd. in the triclinic space group P?1. The difference between the 2 structures lies in the orientation of the 2 alkyl chains with respect to the C(arom.)-O bond. In the title compd., the O-Calkyl-Calkyl-Calkyl torsion angle is 55.8(5)°, while in the bromo analog this angle is -179.1(2)°. In the title compd., the C-atoms of the alkyl chain are almost coplanar [max. deviation of 0.052(5) Å] and this mean plane is inclined to the benzene ring by 50.3(3)°. In the bromo-analog, these 2 mean planes are almost coplanar, making a dihedral angle of 4.1(2)°. Another difference between the crystal structures of the 2 compds. is that in the title compd. there are no halide...halide interactions. Instead, symmetry-related mols. are linked via C-H...? contacts, forming a 2D network. Crystal data: monoclinic, P21/n, a = 9.441(9), b = 7.8455(6), c = 13.457(2) Å, ? = 92.148(12)°, Z = 2, 1216 obsd. reflections with I > 2(I), 101 refined parameters, R[F2 > 2?(F2)] = 0.029, wR(F2) = 0.055. [on SciFinder(R)]