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

Abstract Copper complexes [Cu 2 (μ 2 -C 2 O 4 )(HC 2 O 4 )(L 1 )]·(H 2 C 2 O 4 ) (1), [Cu 2 (Bpz ∗ T-OEt) 2 Cl 2 CuCl 4 ] (Bpz ∗ T-EtOH = L 2 ) ( 2 ) and [Cu 2 (Bpz ∗ T-O) 4 ]·4pz ∗ ·4H 2 O ( 3 ) (Bpz ∗ T-O = L 3 ) (L 1  = 2,4-bis(3,5-dimethyl-1 H -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 ·2H 2 O, oxalic acid, L 1 (for 1 ) or Bpz ∗ T (for 2 and 3 ) and CuCl 2 ·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 H 2 O–DMF–KBr at the constant temperature of 30 ± 0.5 °C with a buffer solution of NaH 2 PO 4 –Na 2 HPO 4 (pH 5.8), indicating that they can be considered as a potential functional model of bromoperoxidase.