The effect of the conformation of flexible carboxylate ligands on the structures of metal-organic supramoleculesThis article is part of a themed issue on Coordination polymers: structure and function.Electronic supplementary information (ESI) available: Structural figures and TGA data for complexes 1-3. CCDC 775311-775313. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c0nj00328j

Three flexible bent dicarboxylate ligands, 2,2′-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene)bis(sulfanediyl)dibenzoic acid (H 2 L 1 ), 2,2′-(1,4-phenylenebis(methylene))bis(sulfanediyl)dibenzoic acid (H 2 L 9 ) and 2,2′-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene)bis(oxy)dibenzoic acid (H 2 L 10 ), have been designed and synthesized. The positions of the functional substituents are in 1,4-positions of the central benzene ring, and all the ligands can adopt syn and anti conformations. By applying these flexible ligands to assemble with thulium ions or zinc ions, three metal-organic supramolecules with metallamacrocycles or 1D chains have been isolated. L 1 adopts a syn conformation in complex 1 , leading to a 0D metallamacrocycle, L 9 in complex 2 adopts an anti conformation to form a 1D "rainbow-like" chain while L 10 in complex 3 adopts both syn and anti conformations. L 10 in a syn conformation connects Zn 4 (OH) 2 (CO 2 ) 4 SBU to form a 0D metallamacrocycle, which is further connected by the ligand in an anti conformation to generate a 1D coordination polymer. Three metal-organic supramolecules constructed from flexible dicarboxylate ligands have been synthesized, and the effect of the conformation of the ligands on the final structures has been discussed.