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Donor–π–acceptor fluorophores that consist of an electron‐donating amino group and an electron‐accepting triarylborane moiety generally exhibit substantial solvatochromism in their fluorescence while retaining high fluorescence quantum yields even in polar media. Herein, we report a new family of this compound class, which bears ortho‐P(=X)R2‐substituted phenyl groups (X=O or S) as a photodissociative module. The P=X moiety that intramolecularly coordinates to the boron atom undergoes dissociation in the excited state, giving rise to dual emission from the corresponding tetra‐ and tricoordinate boron species. The susceptibility of the systems to photodissociation depends on the coordination ability of the P=O and P=S moieties, whereby the latter facilitates dissociation. The intensity ratios of the dual emission bands are sensitive to environmental parameters, including temperature, solution polarity, and the viscosity of the medium. Moreover, precise tuning of the P(=X)R2 group and the electron‐donating amino moiety led to single‐molecule white emission in solution. [ABSTRACT FROM AUTHOR]

We report a new design strategy for an excited‐state intramolecular proton transfer (ESIPT) fluorophore that can be used in acidic media. A photobasic pyridine‐centered donor‐acceptor‐donor‐type fluorophore is combined with a basic trialkylamine "strap". In the presence of an acid, protonation occurs predominantly at the amine moiety in the ground state. A single‐crystal X‐ray diffraction analysis confirmed the formation of a pre‐organized intramolecular hydrogen‐bonded structure between the resulting ammonium moiety and the pyridine ring. Upon excitation, the intramolecular charge‐transfer transition increases the basicity of the pyridine moiety in the excited state, resulting in proton transfer from the amine to the pyridine moiety. Consequently, the fluorophore takes on a polymethine‐dye character in the ESIPT state, which gives rise to significantly red‐shifted emission with an increased fluorescence quantum yield. [ABSTRACT FROM AUTHOR]

Keywords: Boron; Donor-Acceptor Systems; Excited State; Fluorescence; Stimulus-Responsiveness EN Boron Donor-Acceptor Systems Excited State Fluorescence Stimulus-Responsiveness 1 1 1 06/20/23 20230626 NES 230626 B Dual-emissive b triarylborane-based donor- -acceptor fluorophores sensitive to environmental parameters, including temperature, solvent polarity, and viscosity of the medium, are reported by Shigehiro Yamaguchi and co-workers in their Research Article (e202303725). Boron, Donor-Acceptor Systems, Excited State, Fluorescence, Stimulus-Responsiveness Back Cover: Photodissociative Modules that Control Dual-Emission Properties in Donor- -Acceptor Organoborane Fluorophores (Angew. [Extracted from the article]

The intramolecularly coordinated B-X=P bond undergoes dissociation in the excited state, giving rise to bright emissions from the two different states. Boron, Donor-Acceptor Systems, Excited State, Fluorescence, Stimulus-Responsiveness Keywords: Boron; Donor-Acceptor Systems; Excited State; Fluorescence; Stimulus-Responsiveness EN Boron Donor-Acceptor Systems Excited State Fluorescence Stimulus-Responsiveness 1 1 1 06/20/23 20230626 NES 230626 B Dual-emissive b triarylborane-based donor- -acceptor fluorophores sensitive to environmental parameters, including temperature, solvent polarity, and viscosity of the medium, are reported by Shigehiro Yamaguchi and co-workers in their Research Article (e202303725). [Extracted from the article]