Novel amide coupled phthalocyanines: Synthesis and structure-property relationship for electrocatalysis and sensing of hydroquinone

Abstract

Listen

Translate article

• Amide bridged CoPc macrocyclic dyes were prepared and elucidated the structure using physico-chemical techniques. • The amide CoPc was deposited on glassy carbon electrodeandcharacterized with SEM and electrochemical techniques. • Among different CoPcR 4 /GCE electrode, CoTAMFCAPc/GCE showed better sensitivity for QH 2 with lower LOD. • CoTAMFCAPc/GCE is stable and selective for QH 2 and has been applied for the detection of QH 2 in real samples. Analogs of amide bridge cobalt phthalocyanine complexes with different peripheral substituents have been prepared with good yield and these dyes possess dark green colour. These phthalocyanine complexes are characterized by elemental analysis, absorption spectra, infrared spectroscopy, mass and electrochemical methods. An attempt has been made to understand the structure–property relationship of these molecules for electrochemical properties. Hence, uniform and thin film of amide phthalocyanine ( Pc ) complex was administered on glassy carbon electrode (GCE) surface and scanning electron microscopy (SEM) images displayed the uniform distribution of the macrocycle on the surface. The modified electrodes are found to be electroactive and the Ohmic/Faradic surface response of the film is studied using electrochemical impedance spectroscopy (EIS). The formal Co(II)/(I) redox behavior of the substituted phthalocyanines have been explained using Hammett parameter. The electrode surface modified with terminal amide bridged Co-N4 macrocyclic complexes were applied for the sensing of hydroquinone (QH 2 ). An attempt was made to understand the influence of structure and functional groups on the electrocatalytic activity. Cyclic voltammetry (CV) displayed significantly increasing current trend for QH 2 in the quantitative range 200–2200 nM at the furan containing amide phthalocyanine (CoTAMFCAPc) electrode with a low limit of detection (LOD) of 65 nM. Further, the chronoamperometric analysis showed better linear response for QH 2 in 170–1530 nM range with LOD 56 nM at GCE/CoTAMFCAPc electrode compared to other molecules. The fabricated GCE/CoTAMFCAPc electrode demonstrated good stability and selectivity for QH 2 in presence of molecules with similar structure which co-exist along with QH 2 . GCE/CoTAMFCAPc electrode can be employed for practical application and produced superior recovery values for QH 2 .