Cu(II) and Co(II) complexes of benzimidazole derivative: Structures, catecholase like activities and interaction studies with hydrogen peroxide

Abstract Present study describes the synthesis and single crystal X-ray structures of two metal complexes of benzimidazole derivative (PBI), viz. the Cu(II) complex, [Cu(PBI) 2 (NCS)]ClO 4 (1) and a Co(II) complex, [Co(PBI) 2 (NCS) 1.75 Cl 0.25 ] (2). The Cu(II) complex (1) shows catecholase like activity having K cat  = 1.84 × 10 4 h −1 . Moreover, interactions of the complexes with hydrogen peroxide have been investigated using fluorescence spectroscopy. The interaction constant of 1 and 2 for H 2 O 2 are 6.67 × 10 2  M −1 and 1.049 × 10 3  M −1 while their detection limits for H 2 O 2 are 3.37 × 10 −7  M and 2.46 × 10 −7  M respectively.