Kawashiro Midori, Mori Tatsuya, Ito Masato, Ando Naoki, Yamaguchi Shigehiro
Department of Chemistry, Graduate School of Science and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo, Chikusa, Nagoya, 464-8602, Japan.
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo, Chikusa, Nagoya, 464-8601, Japan.
Angew Chem Int Ed Engl. 2023 Jun 26;62(26):e202303725. doi: 10.1002/anie.202303725. Epub 2023 May 4.
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)R -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)R group and the electron-donating amino moiety led to single-molecule white emission in solution.
由供电子氨基和吸电子三芳基硼烷部分组成的供体-π-受体荧光团通常在荧光中表现出显著的溶剂化显色性，即使在极性介质中也能保持高荧光量子产率。在此，我们报道了这类化合物的一个新家族，其带有邻位-P(=X)R-取代苯基（X = O或S）作为光解离模块。分子内与硼原子配位的P=X部分在激发态下发生解离，产生相应四配位和三配位硼物种的双重发射。该体系对光解离的敏感性取决于P=O和P=S部分的配位能力，其中后者促进解离。双重发射带的强度比对于包括温度、溶液极性和介质粘度在内的环境参数很敏感。此外，对P(=X)R基团和供电子氨基部分的精确调节导致溶液中的单分子白色发射。
