Cd(II)-coordination polymers with isophthalic acid bearing a hydroxyphenylazo group and substituted bis(imidazole) linkers

Abstract

Four Cd(II) coordination polymers, formulated as {(H(2)betib)(2)[Cd(mu-Hpdia)(2)]center dot H2O center dot MeOH center dot dmf}, (1), {[Cd(mu-Hpdia)(mu-dipib)]center dot dmf}(n) (2), [Cd(mu-Hpdia)(H2O)(2)(mu-betix)(0.5)](n) (3) and [Cd(mu(3)-Hpdia)(MeOH) (mu-bipix)(0.5)](n) (4) (Hpdia: 5-(4-hydroxyphenylazo)isophthalate, betib or bipib: 1,4-bis(2-x-imidazol-1-yl)butane, betix or bipix: 1,4-bis((2-x-imidazol-1-yl)methyl)benzene where x = ethyl- or isopropyl-) were synthesized under the same solvothermal conditions with 5-(4-hydroxyphenylazo)isophthalic acid and flexible or semi-flexible substituted bis(imidazole) linkers, and characterized by elemental analysis, IR spectroscopy, single crystal X-ray diffraction and thermal analysis methods. X-ray analysis results demonstrated that compounds 1-4 displayed 1D, 2D and 3D structures. In 1, the flexible betib ligand was protonated and the 2D structure formed by Hpdia was extended by hydrogen bonding to a 3D supramolecular network with the rtw topology. The hydrogen-bonded structure of 2 displayed a two-fold 3D -> 3D interpenetrated supramolecular network with the tcj/hc topology. Compounds 3 and 4, synthesized using semi-flexible bis(imidazol) ligands, exhibited 1D and 3D frameworks, respectively. The thermal, optical and photoluminescence properties of the compounds were also investigated. (C) 2020 Elsevier Ltd. All rights reserved.