1,3a,6a-Triazapentalene Systems: Towards Extended Planar Materials
Synthesis and Evaluation of a 1,3a,6a-Triazapentalene (TAP)-Bonded System.
Chem. Eur. J. 2018;
18 January 2019 (online)
Designing linearly bonded aromatic systems with a planar form introduces new materials with highly conductive properties for potential applications in molecular wires. A recently developed 1,3a,6a-triazapentalene (TAP) has been developed as a novel fluorescent chromophore with a 10π-electron system in a compact bicyclo[3.3.0]octane skeleton (highlighted core of 5). The dimer and trimer (8 and 10, respectively) were synthesized sequentially and characterized by a linear connection in planar form with alternating charges between the linked monomers.
Tap units were synthesized by click reactions of alkynes (1) with azidotriflate (2), which could be extended by sequential reactions repeating the same procedure. The alternating charge led to unique fluorescence properties derived from changes in the aggregation state under concentrated conditions. Extension of the bonded systems also resulted in increased fluorescence in the solid state and fluorescence change upon mechanical grinding.