Open layers based on metal-oxide chains linked by cyclohexanedicarboxylate ligands

Three layered metal-oxide organic compounds, In(OH)(1,4-chdc), (1), Cr(OH)(1,4-chdc), (2), and In(OH)(1,2-chdc), (3), (H(2)chdc=cyclohexanedicarboxylic acid) were synthesized and characterized by thermogravimetric analysis, infrared spectroscopy, and X-ray diffraction. All three structures are formed by stacking electro- neutral layers in a simple AA sequence. The layers are built by cross-linking -OH-MOH-M- chains with the chdc anions. Unlike the flat 1,4-benzenedicarboxylate ligand which was previously shown to connect similar metal-oxide chains into porous 3D frameworks, the bent chdc ligands link the chains to form open layers with narrow intra-layer channels. From a mixture of cis- and trans-conformations of 1,4-chdc, only the e,a-cis conformation is incorporated in 1 and 2. (C) 2009 Elsevier Masson SAS. All rights reserved.