Enantiomers of conformation-flexible cyclopentane-1,2,3,4-tetracarboxylate in metal–organic frameworksElectronic supplementary information (ESI) available: Additional figures, TGA, XPRD, free energies of various cptc conformations and crystallographic data. CCDC reference numbers 775638–775641. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c0ce00144a

Four novel coordination polymers, [Mn2(cptc)(2,2′-bpy)(H2O)]·H2O (1), [Mn2(cptc)(phen)(H2O)]·H2O (2), Mn4(cptc)2(phen)4(H2O)2]·3H2O (3) and [Cd2(cptc)(H2O)3] (4) (H4cptc = cyclopentane-1,2,3,4-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized by hydrothermal reactions of flexible (1S,2S,3R,4R)-H4cptc with MnCl2/CdCl2. By breaking the mirror plane of symmetry, the meso-cptc ligand is successfully converted into two pairs of enantiomers, the (1R,2S,3S,4R)- and (1S,2R,3R,4S)-cptc groups in 1–3are unprecedented while the documented (1R,2R,3R,4S)- and (1S,2S,3S,4R)-cptc enantiomers exhibit an unprecedented μ6-mode in 4. Layered 1and 2show similar structures and are constructed by centrosymmetric tetranuclear units. 3is a binodal (3,4)-connected layer with Schläfli symbols of (53)2(54·82), in which cptc exhibits two types of μ5-mode bonding. 4has a 3-D pillar layered structure composed of neutral [Cd(cptc)]nlayers and octahedral CdO6pillars. The presence probability of different enantiomers is in agreement with the relative stability of different conformations of cptc calculated by time-dependent density functional theory (TD-DFT). [ABSTRACT FROM AUTHOR]