5, 6, 12, 13‐Tetraazaperopyrenes as Unique Photonic and Mechanochromic Fluorophores. Issue 25 (24th January 2020) - Yuan, Wei
Abstract: 5, 6, 12, 13‐Tetraazaperopyrenes with different number of tert‐butyl groups (c‐TAPP‐T, c‐TAPP‐H) were synthesized, via four‐fold Bischler–Napieralski cyclization as the key step. As deduced from the single‐crystal structures and optical properties, N‐doping and substitution type allow for a precise control of intermolecular interactions. Compared to the reported 1, 3, 8, 10‐tetraazaperopyrenes, significantly different packing modes were found in 5, 6, 12, 13‐tetraazaperopyrenes. Going from c‐TAPP‐T to c‐TAPP‐H, two additional tert‐butyl groups lead to different preferential growth directions, affording 1D and 2D microcrystals, respectively. Most importantly, both microcrystals exhibit excellent optical waveguide properties with extraordinarily low loss coefficients and unique polarization features. Although c‐TAPP‐H possesses a rigid and planar core, its crystals display an exceptional mechanochromic fluorescence, which, again, depends on the mode of molecular packing. Abstract : Regioselective N‐doping of peropyrenes for fluorescent tailored microcrystals was achieved. 5, 6, 12, 13‐Tetraazaperopyrene derivatives were synthesized, the crystals of which showed excellent optical waveguide properties and exceptional mechanochromic fluorescence.