Synthesis, Structure, and Properties of a Dinuclear Cu(II) Coordination Polymer Based on Quinoxaline and 3,3-Thiodipropionic Acid Ligands

Abstract

The coordination polymer [Cu 2 (TDPH) 4 (QNX)].DMF, (QNX = Quinoxaline; TDPH = 3,3thiodipropionic acid), has been prepared by reaction of copper acetate, TDPH, and quinoxaline. The compound was characterized by elemental analysis, FTIR spectroscopy, and single-crystal Xray diffraction. The crystal is monoclinic with a P21/n space group and dimensions of a = 12.889(3) Å, b = 14.983(4) Å, c = 14.091(3) Å, α = 90 °, β = 90.200(11) °, γ = 90 °, V = 2721.18 (2) Å 3 , Z = 4. The ligands are hexagonally coordinated to the Cu(II) centre in the form of Cu2O4N with one nitrogen atom from the quinoxaline ligand, and four oxygen atoms from four TDPH molecules in a monodentate fashion. The Cu-Cu bond length was 2.642(1) and 2.629(1) Å for the Cu1-Cu1 and Cu2-Cu2 bonds. The QNX ligand bridged the two copper atoms. The catalytic reduction of 4-nitrophenol to 4-aminophenol using NaBH4 in the presence of [Cu 2 (TDPH) 4 (QNX)].DMF, as catalyst was completed within 11 minutes. The 4-aminophenol product was confirmed using 1 H NMR spectroscopy.

Coordination Compounds of Cu, Zn, and Ni with Dicarboxylic Acids and N Donor Ligands, and Their Biological Activity: A Review

“…While other complexes of copper with 3,3′-thiodipropionic acid show chromotropism or biological activity, the polymeric {[Cu 2 (tdp) 4 (QX)] n ·DMF} n has catalytic effects in the reduction of 4-nitrophenol [ 80 ]. The complex belongs to MOFs and is characterized by the existence of 2.647 nm cavities, which allow the adsorption of nitrogen molecules.…”