9‐(Diphenylphosphoryl)‐10‐(phenylethynyl)anthracene Derivatives: Synthesis and Implications for the Substituent and Solvent Effects on the Light‐Emitting Properties

Abstract

Herein, we report a series of 9‐(diphenylphosphoryl)‐10‐(phenylethynyl)anthracenes (DPPPEAs) as novel fluorescent 9,10‐disubstituted anthracene derivatives. The DPPPEAs were prepared by Sonogashira coupling of (10‐bromoanthracen‐9‐yl)diphenylphosphine oxide with terminal arylacetylenes, and their structures were fully characterized. UV/Vis fluorescence spectroscopy and theoretical calculations were used to evaluate substituent effects on fluorescence properties of DPPPEAs. The nature of emissive excited state of DPPPEAs was found to vary greatly depending on the substituent, solvent, and temperature. Unsubstituted DPPPEA emitted intense fluorescence from locally excited (LE) state, whereas donor‐acceptor (D‐A) type DPPPEAs substituted with diphenylamino groups showed strong solvatofluorochromism derived from the charge‐transfer (CT) state. Notably, carbazolyl derivatives exhibited fluorescence from LE hybridized with CT state. The disappearance of CT emission in rigid media suggests that solvent reorganization plays a crucial role in producing large Stokes shifts of D‐A type derivatives. The DPPPEAs have also been found to function as annihilators in porphyrin‐sensitized triplet–triplet annihilation processes.

Photon Upconversion with a Low Threshold Excitation Intensity in Plain Water

“…To gain further insight into the TTA-UC kinetics in this homogeneous aqueous solution, 28 the time dependence of the emissions for the same mixture of PdTPPS 4− and DCDPA 2− in water was evaluated using a nanosecond pulse laser with λ = 532 nm. The emission spectra measured by the pulse laser excitation (Figures S6C and S7) were almost identical to those obtained in previous independent measurements (Figures 2A, 3B, and S6).…”

Anthracene–naphthylacetonitrile fluorescent isomers and Cl/H substituent dependent molecular packing, solid-state fluorescence and mechanofluorochromism

“…[45][46][47] Further, anthracene substitutional groups exhibited a strong influence on the orientation of anthracene and its solid-state fluorescence properties. 48 Naphthalene is another planar π-conjugated unit utilized for developing fluorescence molecules for various applications. [49][50][51] The integration of planar anthracene and naphthalene might exhibit varied molecular assembly and stacking and produce improved tunable solid-state fluorescence.…”

Origin of the Delayed Fluorescence by Triplet–Triplet Annihilation in Solids with a Power Law Exponent of between −1/2 and −1

“…Low-energy photons can be converted to higher-energy photons by a photon up-conversion process; such photon up-conversion has attracted interest for using low-energy photons in the solar spectrum, in organic light-emitting diodes, and in bioimaging, among other applications. − Recently, among various photon up-conversion processes, triplet–triplet annihilation (TTA) up-conversion has been intensively studied for its efficient up-conversion under low excitation power densities. ,− ,− Although efficient TTA up-conversion in solutions has been reported, ,− TTA up-conversion in solid matrixes is preferred for practical applications. ,− ,,− TTA in solutions occurs when excited molecules are brought into a close-contact state by diffusion at room temperature; when the molecules are excited by pulsed light, the fluorescence decay from the excited singlet state generated by the TTA shows relatively simple exponential kinetics, with a typical lifetime of one-half the natural lifetime of the triplet exciton. ,− Even the exceptional case of nonexponential kinetics can be theoretically interpreted on the basis of the bulk second-order reaction influenced by the first-order decay originating from the natural lifetime of the triplet exciton. ,− In solid matrixes, the emission decay kinetics after pulsed-light excitation is more complex because it depends on the excitation light intensity and the temperature. The complexity of the TTA kinetics in solid matrixes compared with that in solutions might originate from processes such as the slow mixing of triplet excitons by migration,the strong dependence on the initial distribution of triplet excitons, and the anisotropic random walk of excitons, but the process underlying the different TTA kinetics has not yet been elucidated.…”