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

摘要

Copper complexes [Cu-2(mu(2)-C2O4)(HC2O4)(L-1)]center dot(H2C2O4) (1), [Cu-2(Bpz*T-bEt)(2)Cl2CuCl4] (Bpz*T-EtOH = L-2) (2) and [Cu-2(Bpz*T-O)(4)]center dot 4pz*center dot 4H(2)O (3) (Bpz*T-O = L-3) (L-1 = 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)center dot 2H(2)O, oxalic acid, L-1 (for 1) or Bpz*T (for 2 and 3) and CuCl2 center dot 2H(2)O 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 degrees C with a buffer solution of NaH2PO4-Na2HPO4 (pH 5.8), indicating that they can be considered as a potential functional model of bromoperoxidase. (C) 2015 Elsevier Ltd. All rights reserved.