Electrochemical Detection of Nitrite on Electrodes Modified by Click Chemistry Using Asymmetrical Co(II) and Mn(III) Phthalocyanines Containing Push-Pull Substituents

The more conventional route to synthesizing asymmetric push-pull phthalocyanines (Pcs) involves pairing electron-donating substituents with electron-withdrawing groups in either an A(3)B or AB(3) manner. In this work, a push-pull system fashioned from a substituent bearing different functional groups was created. Symmetric and asymmetric cobalt and manganese Pcs in which acetaminophen was the dominant substituent were synthesized where the asymmetric analogues bore an alkyne-terminated substituent. These complexes were applied as sensors towards the electro-oxidation of nitrite. In addition to comparing the asymmetric Pcs to the symmetric counterparts, an assessment on the different central metals as well as the method of electrode modification was made. From the studies performed, the results showed that the manganese complexes are generally better suited (more so when clicked on to the electrode) in the electrocatalysis of nitrite with a limit of detection and a catalytic rate values of 2.15 mu M and 6.91 x 10(6 )s(-1) M-1 being recorded for the asymmetric MnPc.

Automated summary

In this study, asymmetric push-pull phthalocyanines were successfully synthesized for the electrocatalysis of nitrite, with manganese complexes showing better suitability. By comparing symmetric and asymmetric complexes, and assessing different central metals and electrode modification methods, the results indicated the superior performance of the manganese complexes, particularly when attached to the electrode.