Volcano correlations for the reactivity of surface-confined cobalt N4-macrocyclics for the electrocatalytic oxidation of 2-mercaptoacetate

Optimizing the Electrocatalytic Activity of Surface Confined Co Macrocyclics for the Electrooxidation of Thiocyanate at pH 4

“…Cyclic voltammograms provided very clear peaks that can be attributed to the Co(II)/(I) reversible process [62]. Similar curves have been reported in earlier work using these complexes [45][46][47][48][49] Figure 1 compares the Co(II)/(I) formal potentials of several CoPcs with the LUMO energy of the complexes, which has metal-character, since the incoming electron to the Co(II) to give Co(I) will occupy the LUMO orbital. The correlation in Figure 1 is self explanatory.…”

“…It is difficult to estimate the slope of the falling region in Figure 4 due to the scatter of the data. However, if the data point due to 4b(Pyr)CoPz) is not considered, the slope of the falling region is À0.250 V/decade, which is close to the value observed for 3 reactions studied before, namely, the oxidation of 2-mercaptoethanol, [44,45] mercaptoacetate [46] and of aminoethanethiol [47]. If the data point of 4b(Pyr)CoPz) is considered, a straight line can be drawn presenting a slope of À3.0 V/decade which does not make any physical sense, according to the interpretation of the data that follows.…”

“…A long mathematical derivation has been described in detail in previous publications [45][46][47] for the oxidation of several thiols, but it can be demonstrated that q, the coverage of thiocyanate molecules bound to the Co sites is given by:…”

Metallophthalocyanine-based molecular materials as catalysts for electrochemical reactions

“…In earlier studies of the electrocatalytic activity of MPcs for the oxidation of thiols such as 2-ME and 2-aminoethanethiol [290,333,334,[338][339][340] the catalytic activity (measured as current at constant potential) followed a linear correlation with the redox potential (driving force) of the complex, when immobilized on graphite electrodes. The activity increases as the M(II)/M(I) formal potential of the catalyst becomes more negative, that is to say, the activity increases when the driving force of the catalyst decreases.…”

Comparative electrocatalytic behavior of self-assembled monolayer of thiol derivatised Co (II) phthalocyanines on gold disk, ultramicro cylinder and fiber electrodes

“…Figure 2b shows that complex 1-SAM exhibits more blockage of the gold oxidation/reduction process in 1 9 10 -5 mol cm -3 KOH compared to complex 2-SAM which still shows the presence of gold oxide peaks (though small) even after modification, hence suggesting larger ion permeability for the latter. The broad peaks between ?0.25 and 0.4 V are most probably due to the Co III Pc -2 /Co II Pc -2 process, in comparison with literature for adsorbed thio substituted CoPc complexes [29,30]. Figure 2c shows the inhibition of the Fe …”