Azide glassy carbon electrodes

The multielectron reduction of alkylazides catalyzed by various [4-Fe]n and [Mo-Fe]m clusters has been achieved by c.p.e. in homogeneous systems and at modified glassy-carbon electrodes [168-169]. Dithionite reduction of alkyl-azide is catalyzed by [Fe4S4( SC6H4-4-n-C8H 7)4 2 [170] and MoFe3S4... 

Fig. 7.33 Binding of dioxygen to two proximal Cu centers of 3-ethynyl-phenanthroline covalently attached to an azide-modified glassy carbon electrode according to Chidsey et aL [169]...

Chidsey et al. [169] have also studied the catalytic activity of a Cu(I) complex of 3-ethynyl-phenanthroline covalently attached to an azide-modified glassy carbon electrode. This catalyst promotes the four-electron reduction of O2 at pH 4.8 (acetate buffer). In contrast to what is observed by Anson et al. [156-158, 170] using Cu phenanthroline, Chidsey et al. found a second-order dependence of the rates on Cu coverage at moderate overpotentials. This suggests that O2 interacts with two Cu centers simultaneously, forming a bridge structure, as illustrated in Fig. 7.33. 

Summary of FIA-EC Data for Azide at Diamond and Glassy Carbon Electrodes... 

N2H4 + NH3 when carried out in an aqueous azide solution with a glassy carbon electrode pretreated with an [M02Fe6Sa(SC6H5)9] " solution in CH3CN. The rate of N2H4 formation increases as the pH is lowered from 10 to 5 a mechanism involving the reduction of coordinated HN3 is proposed [6]. 

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