Inclusion compounds of cis- and trans-3,3-bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid hosts with ethanol guests. Crystal structures and selective inclusion modes

Abstract

Structures of the crystalline inclusion complexes of cis- and trans-3,3-bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid hosts, 1 and 2, have been studied by X-ray diffraction. Crystal data: 1·EtOH (1 : 1), monoclinic, C2/c, a= 21.9870(7), b= 10.7398(3), c= 18.2478(4)Å, β= 110.46(2)°, Z= 8, R= 0.051 for 2085 reflections collected at room temperature. 2·EtOH (1 : 2), monoclinic, P2₁/c, a= 14.619(2), b= 11.032(2), c= 15.595(3)Å, β= 116.37(1)°, Z= 4, R= 0.052 for 1881 reflections collected at 173(1) K. The molecular geometries of 1 and 2 are rather similar, but 1 behaves as a monofunctional host owing to the intramolecular hydrogen bond between the two carboxyl groups, whereas 2 is a typical bifunctional host, as revealed by the different host: guest stoichiometries. Both hosts form endless H-bonded chains with ethanol guests, but the chains are differently organized: 1 creates supramolecular helices with alcoholic guests, whereas the H-bond scheme in 2·EtOH (1 : 2 ) is characterized by closed loops of hydrogen bonds.