Electrode Modification Using Alkyne Manganese Phthalocyanine and Click Chemistry for Electrocatalysis

Abstract

In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3‐dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X‐ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.

Electrode Modification through Click Chemistry Using Ni and Co Alkyne Phthalocyanines for Electrocatalytic Detection of Hydrazine

“…A linear relationship was observed and k cat found to be 7.84 × 10 2 M −1 s −1 for 2 ‐clicked‐GCE and 0.666 M −1 s −1 for 3 ‐clicked‐GCE. The 2 ‐clicked‐GCE result is comparable to previous reports for the corresponding FePc derivative at 8.84 × 10 2 M −1 s −1 but lower than the MnPc derivative at 4.1 × 10 3 M −1 s −1 . However, 3 ‐clicked‐GCE produced a very low value, indicating an unfavourable response towards hydrazine detection when compared to other reported electrodes of this nature.…”

“…The sensitivity found for 2 ‐clicked‐GCE was 51.3 μA / mM and for 3 ‐clicked‐GCEthe sensitivity found was 111.2 μA / mM. The LoDs are in in the micromolar range as was the case for FePc derivative also reported by our group .…”

“…NiPc derivatives are known to form O−Ni−O oxo bridges in alkaline aqueous solution which is known to influence their electrocatalytic behaviour , hence their catalytic activity is compared with that of CoPc derivative. We compared the electrocatalytic behaviour of alkyne substituted CoPc and NiPc towards the detection of hydrazine with that of the corresponding reported MnPc and FePc derivatives.…”

Effects of Substituents on the Electrocatalytic Activity of Cobalt Phthalocyanines when Conjugated to Graphene Quantum Dots

“…The bare glassy carbon plate (BGCP) is more conductive than the BGCP/ 1 @GQDs(conj). We have reported on the approach curves showing low conductivity of electrodes modified with Pc by grafting followed by click chemistry , with the electrode still being catalytic for the analyte interest.…”

“…Sequentially modified electrodes showed less favourable detection limits compared to the above electrodes, showing the importance of conjugating the Pc with GQDs before electrode modification. The LOD reported in this work are less favourable than reported in literature for hydrazine oxidation when MnPc or FePc derivatives are clicked onto the GCE, which were in the nanomolar range. The LOD value for the conjugated complex GCE/2@GQDs is slightly lower than the 9 μM reported for a related CoPc derivative .…”