Grinding-induced equimolar complex formation between thiourea and ethenzamide.
We prepared and characterized a grinding-induced equimolar complex of thiourea with ethenzamide. When thiourea and ethenzamide were co-ground at a molar ratio of 3 : 1, new powder X-ray diffraction (PXRD) peaks were observed in addition to PXRD peaks of thiourea crystals. The optimum stoichiometry of the new structure was confirmed as 1 : 1 mol/mol. Effect of grinding time on the thiourea-ethenzamide equimolar complex formation was investigated by using PXRD, differential scanning calorimetry and Fourier transform infrared spectroscopy. The equimolar crystal structure was confirmed by X-ray diffraction measurements of the single crystal which was recrystallized from ethanol. It was found that the intermolecular hydrogen bond formations between thiourea and ethenzamide molecules contributed to the equimolar complex formation. The complex formation was not observed in the cases where benzamide, salicylamide or 3-ethoxybenzamide was co-ground with thiourea. 2-Alcoxyl benzamide structures should be required for the grinding-induced equimolar complex formation with thiourea.
Crystal structure of 2-pentyloxybenzamide
In the nearly planar 2-pentyloxybenzamide molecule, there is an intramolecular N—H⋯O hydrogen bond involving one amide proton and the ether oxygen. In the crystal, pairs of N—H⋯O hydrogen bonds organize molecules into inversion dimers lying in two planes, (121) and (11).
Cholic acid inclusion compounds with ketone guests
Cholic acid forms inclusion compounds with acetone, methyl ethyl ketone and diethyl ketone. Crystal structures with these closely related guest molecules indicate variations in packing which result in respectively: unusual 2∶3 host: guest stoichiometry and loss of the 21 screw axis, doubling of the c axis with formation of two different channels and the usualP21 structure with 1∶1 host: guest stoichiometry.