A 3D porous zinc MOF constructed from a flexible tripodal ligand: Synthesis, structure, and photoluminescence property

A new metal-organic framework, [Zn-5(trencba)(2)(OH)(2)Cl-2 center dot 4H(2)O] (1) [H(3)trencba = N,N,N',N',N,N -trisf(4-carboxylate-2-yl)methyl]-tris(2-aminoethyl)amine], constructed from a flexible tripodal ligand based on C-3 symmetric tris(2-aminoethyl)amine, has been synthesized hydrothermally and characterized by elemental analysis. IR, TG, XRD and single-crystal X-ray diffraction analysis. Compound I contains an unprecedented linear penta-nuclear zinc cluster fragment. Each ligand links four penta-nuclear fragments, and every fragment links eight ligands to generate a three-dimensional non-interpenetrated porous framework. The uncoordinated water molecules were observed trapped in the void pores. Compound I represents the first example of (6,8)-connected 3D bi-nodal framework based on a single kind of organic ligand. The photoluminescence measurements showed that complex I exhibits relatively stronger blue emissions at room temperature than that of the ligand. (C) 2008 Elsevier Inc. All rights reserved.