Luminescent‐Substituted Fluoranthenes—Synthesis, Structure, Electrochemistry, and Optical Properties

Abstract

Six novel fluoranthene derivatives, namely, three terminally substituted and three bis(fluoranthene) units with fluorene, bithiophene, and carbazole spacers, were obtained through [2+2+2] cycloaddition and characterized completely. Based on the conducted studies, the obtained derivatives can be classified as donor-acceptor (D-A) and acceptor-donor-acceptor (A-D-A) systems, in which the fluoranthene unit acts as an electron-withdrawing unit. The optical results revealed that novel fluoranthene derivatives absorb light in the range λ=236-417 nm, which originates from a π→π transition within the conjugated system. The compounds exhibit fluorescence that range from deep blue to green, which mainly arises from intramolecular charge transfer (ICT) states. High Stoke shifts and high quantum yields in solution (ϕ=0.22-0.57) and in the solid state (ϕ=0.18-0.44) have been observed for fluoranthene derivatives. All the derivatives display multistep oxidation processes at low potentials. The electronic structure of the presented compounds is additionally supported by time-dependent DFT computations.

N-Substitution of acridone with electron-donating groups: crystal packing, intramolecular charge transfer and tuneable aggregation induced emission

“…All the emissions in the solid state are red-shied compared to these from the locally excited states in the solutions due to the close intermolecular contacts caused the excimer coupling. 30 The absolute quantum yields are 13% for 2a, 17% for 2b and 2% for 2c, respectively (ESI Table S5 †). The loss of emission intensity in solid state is common for the excited states of the aggregates oen decay or relax to the ground state in the nonradiative manner.…”

Effects of N‐Substitution on the Property of Acridone

“…The fluorescence of the acridone derivatives in solid state were characterized (Figure ). Compared to that in chloroform or cyclohexane solutions, all the compounds show red shift with the fluorescence maxima at 434–605 nm in the solid state due to the excimer coupling or the tendency to form planar conformation thus extended the degree of π conjugation in the solid state . What's more, the emission intensity reduces in the solid state owing to the strong π‐π interactions between the molecules.…”

Synthesis, Structure and Properties of Fused π‐Extended Acridone Derivatives

“…The fluorescence spectra of the acridone derivatives were measured in the solid state (see the supporting information). The emission maxima are red‐shifted in comparison to those measured in the dichloromethane solution due to the close contacts caused excimer coupling . The absolute quantum yields of the acridone derivatives in the solid state are in the range of 0.3 %‐7.1 %.…”