Zinc(ii) coordination polymers with substituted benzenedicarboxylate and tripodal imidazole ligands: syntheses, structures and properties

Abstract

By introducing 1,4-benzenedicarboxylic acid (H₂BDC) with different substituent groups H₂BDC-R (R = NH₂, OH, NO₂) into the Zn(II)-1,3,5-tris(1-imidazolyl)benzene (tib) system, four new zinc(II) coordination polymers, namely [Zn₅(tib)₂(BDC-NH₂)₄(μ₂-OH)₂]·H₂O (1), [Zn₂(tib)(BDC-NH₂)SO₄(H₂O)₂]·5H₂O (2), [Zn₂(tib)₂(HBDC-OH)₂(BDC-OH)]·2H₂O (3) and [Zn(tib)(BDC-NO₂)]·H₂O (4), have been successfully synthesized under solvothermal conditions. Complexes 1 and 2 based on the same H₂BDC-NH₂ show different structures: 1 is a 3-fold interpenetrated 3D framework with point (Schläfli) symbol {5³·6²·7}₂{5³}₂{5⁸·6²·8⁵}, while 2 exhibits a 2D network with {6²·8⁴}{6²·8}₄ topology. 3 and 4 are 2D networks with different topologies of {6³} and {4⁴·6²}, respectively. The structural diversity of 1–4 indicates that the substituent groups of H₂BDC as well as the reaction temperature and solvent play an important role in determining the framework structures and topologies. Furthermore, the sorption and photoluminescence properties of the complexes were investigated.