Electrochemistry of cyclic triimidazoles and their halo derivatives: A casebook for multiple equivalent centers and electrocatalysis. (10th September 2019)

• Record Type: Journal Article
• Authors: Magni, Mirko; Lucenti, Elena; Previtali, Andrea; Mussini, Patrizia Romana; Cariati, Elena
• Is Part Of: Electrochimica acta. Volume 317(2019)
• Page Start: 272
• Page End: 280
• Publication Date: 2019-09-10
• Subjects: Cyclic triazines -- Multiple equivalent redox sites -- Electrocatalysis -- Carbon-halogen bond -- Dissociative electron transfer; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.05.146
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: A family of cyclic triazines, based on the triimidazo[1, 2- a :1′, 2′- c :1″, 2″- e ][1, 3, 5]triazine scaffold, has recently caught attention due to its variegated solid state photoluminescent properties ( e.g., crystallization induced emission, fluomechanochromism, dual fluorescence, room temperature ultralong phosphorescence), tuned by proper functionalization of the cyclic core. From an electrochemical point of view, this family of heteroaromatic cyclic triazines is unexplored. A cyclic voltammetry study is here performed aiming to clarify structure/electroactivity relationship. The peculiar molecular structure of this class of molecules offers a multi-approach case study, spanning from multiple equivalent redox site interactions in small hoops (due to ideally C 3h symmetry) to carbon-halogen bond reactivity in the presence of catalytic metal electrode surfaces (for –Br and –I derivatives). Results point to a poor heteroannular aromaticity along the rigid, planar cyclotrimer, with each equivalent redox site acting quite independently. An unusually higher electrocatalytic performance of gold with respect to silver electrode for the electrocleavage of carbon-halogen bonds (that decreases by increasing number of halo substituents) is tentatively explained in term of a specific interaction between gold and the nitrogen-rich planar cyclotrimer platform. Highlights: Electrochemistry of heteroaromatic compounds widens to cyclic triazines. Structure/electroactivity study was carried out on a family of triimidazo-triazine. Weak interaction between equivalent redox sites was detected. Carbon-halogen bonds break through a dissociative electron transfer (DET). Higher electrocatalytic activity was detected for Au electrode with respect to Ag.