|Co(en)3|1/3[In(ox)2] · 3.5H2O: A zeolitic metal-organic framework templated by Co(en)3Cl3

A new indium oxalate |Co(en)3|1/3[In(ox)2] · 3.5H2O (denoted NKB-1) with a three-dimensional open-framework has been hydrothermally synthesized by using a racemic mixture of chiral metal complex Co(en)3Cl3 as the structure-directing agent. It was characterized by X-ray powder diffraction, inductively coupled plasma, elemental (CHN) and thermogravimetric analyses, and the structure was determined by single-crystal X-ray diffraction analysis. NKB-1 crystallizes in the tetragonal space group I41/amd with a = 21.750(3) Å, c = 12.335(3) Å, and Z = 16. The three-dimensional anionic framework of NKB-1 is built up by alternation of eight-coordinated In-centered polyhedra and oxalate ligands, which possesses a multidimensional 16-ring channels system. Notably, NKB-1 has a zeolitic GIS (gismondine) topological structure, which is the first oxalate compound presenting a zeolitic structure. Computer simulation has been used to determine the possible positions of the metal complex within the channels.