Mimicing bromoperoxidase for copper complexes: Synthesis, structures and properties of Cu(II)–triazine pyrazolyl complex

Copper complexes [Cu2(μ2-C2O4)(HC2O4)(L1)]·(H2C2O4) (1), [Cu2(Bpz∗T-OEt)2Cl2CuCl4] (Bpz∗T-EtOH = L2) (2) and [Cu2(Bpz∗T-O)4]·4pz∗·4H2O (3) (Bpz∗T-O = L3) (L1 = 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-diethylamino-1,3,5-triazine, Bpz∗T = 2,4,6-tri(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine) have been synthesized in the reaction of Cu(Ac)2·2H2O, oxalic acid, L1 (for 1) or Bpz∗T (for 2 and 3) and CuCl2·2H2O with solution methods. They were characterized by elemental analysis, IR, UV–Vis and thermogravimetric analyses (TG), and the single-crystal X-ray diffraction analysis. Structural analysis reveals that center metal Cu atoms in the complexes 1 and 3 are six-coordination modes, forming distorted octahedron geometries with N2, O2 and N6 donors, respectively. While Cu atom in the complex 2 is four-coordination and five-coordination modes, forming tetragonal pyramid and tetrahedron geometry with N3 Cl2 and N6, respectively. The complexes exhibit catalytic bromination activity in a single-pot reaction of the conversion of phenol red to bromophenol blue in a mixed system of H2O–DMF–KBr at the constant temperature of 30 ± 0.5 °C with a buffer solution of NaH2PO4–Na2HPO4 (pH 5.8), indicating that they can be considered as a potential functional model of bromoperoxidase.

Three copper complexes were synthesized. And catalytic bromination activities of the complexes were evaluated by the oxidation reaction of phenol red to bromophenol blue.Figure optionsDownload as PowerPoint slide