Reports: AC4
47243-AC4 New Multi-Redox Heterocycles for Materials Applications
Heterocyclic compounds with redox properties are of interest for materials applications. In this context, we have been working with new heterocycles containing fused-ring quinolizinium, Ru complexes of 2-azinobenzo[1,2,3]triazole (2), and [1,2,4,5]tetrazinium (3) as potential 1-electron redox systems. Recently, we developed a practical method for the preparation of pyrido[1,2-c]benzo[d][1,2,4]triazinium (1a) by photo-assisted cyclization of 2-(2-fluorophenylazo)pyridine (4a) in the presence of Ca(OTs)2. This method was later expanded to other quinolizinium ions (1b-1d). All four ions have been investigated for their structural, spectroscopic, and electrochemical properties, and experimental data was augmented with high-level quantum-mechanical calculations. The new method permitted the preparation of derivatives of pyrido[1,2-c]benzo[d][1,2,4]triazinium such as those with fluoro, methyl, and hydroxymethyl substitunets. This class of compounds will allow us for tuning the photophysical and redox properties of more complex molecular systems. During the past year, we also investigated the preparation of 2-azino-benzo[1,2,3]triazole from 4a and other similar precursors as bidentate lignads for Ru. One such complex has been investigated spectroscopically and electrochemically. We hope to obtain a suitable crystal for XRD analysis.
