Ab-initio structure determination from X-ray powder data and solid-state DFT study of monohydrate and anhydrous cyclohexanespiro-5′-hydantoin

Abstract

Abstract The synthesis, thermal analysis, and crystal structures of cyclohexanespiro-5′-hydantoin monohydrate (I) and its anhydrous form (II) have been reported. The compounds (I) and (II) crystallize in space group Pna21 and P21/c, respectively. In the present work, redetermination of crystal structure of (I) and ab-initio structure analysis of (II) have been accomplished from laboratory X-ray powder diffraction data. The crystal structures of both compounds were solved following direct-space approach, and refined by the Rietveld method and solid-state DFT calculation. The results of two refinement procedures for structure determination from X-ray powder data have been compared. The effect of dehydration of (I) has been revealed in different crystal packing arrangements in (I) and (II). In (I), extensive intermolecular N–H · · · O, and O–H · · · O hydrogen bonds involving lattice water molecules generate a two-dimensional C(5)[R3 3(10)][R4 3(10)] supramolecular assembly, whereas in (II), a C2 2(9)[R2 2(8)] [R2 2(8)] framework is established via intermolecular N–H · · · O hydrogen bonds.