Small-ring inclusion hosts. 4. X-ray crystal structures oftrans-3,3-Bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid and of its inclusion complex with Dimethyl Sulphoxide (1:2)

The crystal structures of the unsolvatedtrans-3,3-bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid (1) and of its inclusion compound with dimethyl sulphoxide,1·DMSO (1:2), have been studied by X-ray diffraction. Crystals of1 show triclinic symmetry (P ) withZ = 4 and the unit cell dimensionsa = 7.617(2),b = 15.321(4),c = 15.297(3) Å, = 109.76(2), = 103.47(1), = 89.87(2)°. FinalR = 0.037 for 3601 reflections collected atT = 153(1) K. Crystals of1·DMSO (1: 2) are monoclinic (P2₁/n) withZ = 4 and cell dimensionsa = 10.744(1),b = 10.806(1),c = 21.302(2) Å, = 101.68(1)°. The clathrate structure was refined toR = 0.034 for 1671 reflections obtained atT = 173(1) K. In the unsolvated host compound cyclic pairs of O-H ... bonds, commonly observed in carboxylic acids, couple the carboxylic functions two by two, thus giving rise to endless chains due to the bifunctionality and thetrans position of the acid groups of1. The complex with DMSO as guest, however, consists of distinct hydrogen-bonded 1:2 host-guest associates, held together by weak intermolecular interactions.Supplementary Data relating to this article have been deposited with the British Library at Boston Spa, Wetherby, West Yorkshire, U.K., as Supplementary Publication No. SUP 82139 (32 pages).For Part 3, see Reference 1].