An anionic two-dimensional indium carboxylate framework derived from a pseudo C 3-symmetric semi-flexible tricarboxylic acid

Abstract

Hydrothermal treatment of indium(III) nitrate with a flexible pseudo C 3-symmetric tricarboxylic acid at 115∘C for 5 days in DMF yields a new layered anionic indium carboxylate framework, [(CH3)2 NH 2)][In(L)(HCOO)(DMF)] n (1) (L = 2,4,6-tris[(4′-carboxyphenoxy)methyl]-1,3,5-trimethylbenzene), existing as two-dimensional sheets. The framework solid has been characterized by elemental analysis, FT-IR spectroscopy, TGA, PXRD and single crystal X-ray diffraction studies. DMF undergoes cleavage to dimethyl ammonium and formate ions, which are incorporated in the framework. A slipped stacking of the two dimensional sheets along a–axis in 1 results in a drastic decrease in the anticipated large porosity of the framework. A two-fold interpenetrated 2-D In(III)-MOF has been synthesized using hydrothermal treatment of flexible tris-acid ligand H3L, indium nitrate and DMF. The MOF features an anionic uninodal 6-connected sql/Shubnikov plane net (3,6) with (36.46.53) topology. DMF decomposes to (CH3)2NH2 + cations which bridge the 2-D sheets through hydrogen bonds in a staggered fashion.