Bola-type PAH-based fluorophores/chemosensors: Synthesis via an unusual clemmensen reduction and photophysical studies

Design, Synthesis, and Photophysical Properties of 5-Aminobiphenyl Substituted [1,2,4]Triazolo[4,3-c]- and [1,2,4]Triazolo[1,5-c]quinazolines

“…For detailed investigation of photophysical properties we measured the fluorescence lifetime (τ) of chromophores 4a – d and 5a – f in toluene ( Figure S21 ), and also calculated radiative decay rate constant (k r ) and non-radiative decay rate constant (k nr ) ( Table 2 ). Emission spectra for fluorophores 4a , b , d and 5a – f fit the single exponential function, whereas decay trace is bi-exponential in the case of compounds 4c and 4e ( Table S9 ); this can probably be attributed to the solvent effect or existence of several emitting states [ 41 , 42 , 43 ]; lifetimes are on a nanosecond timescale. In each series of compounds 4a – c , 5a – c , and 5d – f , diphenylamino-derivatives 4b , 5b , and 5e are characterized by the highest values of singlet excited-state lifetimes in the range of 1.66–1.85 ns.…”

“…Emission spectra were measured on the Horiba FluoroMax-4 (Kyoto, Japan) at room temperature using quartz cells with 1 cm path length. Fluorescence quantum yield of the target compounds in solution and solid state were measured by using the Integrating Sphere Quanta-φ of the Horiba-Fluoromax-4 [ 41 ]. Time-resolved fluorescence measurements were carried out using time-correlated single-photon counting (TCSPC) with a nanosecond LED (λ = 370 nm).…”

Polyaromatic Hydrocarbon (PAH)-Based Aza-POPOPs: Synthesis, Photophysical Studies, and Nitroanalyte Sensing Abilities

“…The materials and devices for the remote detection of explosives, including fluorescence-based ones, are of high demand from the perspective of a high risk of terrorist attack worldwide [ 40 , 41 , 42 ]. Additionally, pyrene derivatives, including azole-appended ones, are known to exhibit a well-pronounced fluorescence “turn-off” response toward common nitroatomatic analytes [ 43 , 44 , 45 , 46 , 47 , 48 ], as well as some nitroaliphatic explosive components [ 49 , 50 ]. In addition, fluorescence- and aggregation-induced emission (AIE)-based small/single-molecule fluorophores, sensors, and probes [ 51 , 52 , 53 , 54 ] are of high demand for biovisualization applications [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ].…”