2-Aryl-3H-1,3-benzazaphosphole Oxides: Synthesis, Optical Properties, and Excited State Intramolecular Proton Transfer

Hiroaki Nakagomi; Nina Murayama; Rika Takegami; Kaori Fujii; Rio Kitakado; Yoshifumi Kimura; Mao Minoura; Haruyuki Nakano; Yoshihiro Matano

doi:10.1002/chem.202400807

2-Aryl-3H-1,3-benzazaphosphole Oxides: Synthesis, Optical Properties, and Excited State Intramolecular Proton Transfer

Chemistry. 2024 Apr 8:e202400807. doi: 10.1002/chem.202400807. Online ahead of print.

Authors

Hiroaki Nakagomi¹, Nina Murayama¹, Rika Takegami², Kaori Fujii², Rio Kitakado², Yoshifumi Kimura², Mao Minoura³, Haruyuki Nakano⁴, Yoshihiro Matano⁵

Affiliations

¹ Department of Fundamental Sciences, Graduate School of Science and Technology, Niigata University, Nishi-ku, Niigata, 950-2181, Japan.
² Department of Molecular Chemistry and Biochemistry, Faculty of Science and Engineering, Doshisha University, Kyotanabe, 610-0321, Japan.
³ Department of Chemistry, College of Science, Rikkyo University, Toshima-ku, Tokyo, 171-8501, Japan.
⁴ Department of Chemistry, Graduate School of Science, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.
⁵ Department of Chemistry, Faculty of Science, Niigata University, Nishi-ku, Niigata, 950-2181, Japan.

PMID: 38590165
DOI: 10.1002/chem.202400807

Abstract

Inclusion of a heteroatom to the phosphole ring is a promising strategy to intrinsically modulate the optical properties of phosphole derivatives. We report on a series of 2-aryl-3H-1,3-benzazaphosphole oxides that were efficiently prepared via sequential C-P cross-coupling, dehydrative [3+2] cycloaddition, and ring-oxidation reactions. The inclusion of one nitrogen atom into the benzophosphole framework caused red shifting of the absorption and emission maxima, reflecting the greater stabilization of the LUMO level. 2-(2-Hydroxyphenyl)benzazaphosphole oxide underwent excited state intramolecular proton transfer and emitted a weak fluorescence from the excited state of the N-H tautomer.

Keywords: Azaphosphole; Dyes/Pigments; Excited state intramolecular proton transfer; Fluorescence.

Abstract

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