Development of Sensor Based on Copper(II) Thiocyanate Pyridine Polymeric Complex for Detection of Catechol

Abstract

The reaction of copper(I) thiocyanate with triphenylphosphine, in pyridine, in air and at room temperature, led to the formation of the copper(II) thiocyanate pyridine polymeric complex [Cu2( $\mu _{\text {3}}$ CO3)(NCS)2(Py)4]n in the form of deep blue needle-like crystals. Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), thermogravimetric analysis (TGA) and single crystal X-ray diffraction analysis (XRD) were performed in order to reveal the identity of the obtained complex. The complex is a coordination polymer that crystallizes in the orthorhombic space group Pnma and has a one-dimensional linear structure running along the crystallographic ${a}$ axis. Here, we report the investigation of the electrochemical properties of this polymeric compound, collected in acetonitrile solution and KClO4 as electrolyte, by cyclic voltammetry and square wave voltammetry. The voltammograms showed four peak pairs related to redox processes of copper ion and electroactive ligands. Moreover, we used this compound as modifier of carbon paste electrodes, whose electrochemical properties were studied in different electrolytes and electrochemical redox probes. These studies demonstrate the valuable electrochemical and electrocatalytic properties of the [Cu2( $\mu _{\text {3}}$ -CO3)(NCS)2(Py)4]npolymerimmobilized in the carbonaceous matrix. The sensor developed by using the carbon paste method has shown excellent sensitivity for catechol, good repeatability, selectivity, stability, and applicability in detection of catechol in water samples.