Five New Cd(II) Complexes Induced by Reaction Conditions and Coordination Modes of 5-(1<i>H</i>-Tetrazol-5-yl)isophthalic Acid Ligand: Structures and Luminescence

Abstract

Five new Cd(II) complexes, {[Cd1.5(tzia)(H2O)2]·H2O}n (1), {[Cd1.5(tzia)(H2O)4]·1.5H2O}n (2), [Cd(H2tzia)2(H2O)4]·H2O (3), [Cd5(μ3-OH)(tzia)3(H2O)7]·2H2O}n (4), and {[Cd2(μ3-OH)(tzia)(H2O)2]·H2O}n (5) (H3tzia = 5-(1H-tetrazol-5-yl)isophthalic acid), were assembled employing a tetrazolyl-carboxyl ligand H3tzia with Cd(II) ions, revealing versatile structures from zero-dimensional (0D) mononuclear molecule, 2D layer to 3D framework, in which five new types of coordination modes of H3tzia were observed. Complex 1 shows a 3D (3,6)-connected ant net based on trinuclear [Cd3(COO)2(N4C)2] cluster; 2 forms an unusual 3D (3,4)-connected 3,4T1 net with 1D tubes based on the 26-membered metallocycles; 3 is a mononuclear molecule; 4 displays an unprecedented (3,4,10)-connected 2D layer based on pentanuclear [Cd5(μ3-OH)(COO)2(N4C)3] cluster; 5 is a 3D porous framework containing 1D Cd-hydroxy-tetrazolyl ribbons. Complexes 1–5 exhibit strong luminescence with different energies resulted from the various coordination modes of tzia. The mechanism of luminescence was further investigated by density functional theory (DFT) calculations.