Novel heterocyclic quinol-type fluorophores (4 a-c) and (5 a-c) that contain substituents (R = Me, Bu, Ph) with nonconjugated linkages to the chromophore skeleton have been synthesized and their photophysical properties have been investigated in solution and in the solid state. Considerable differences in the absorption and fluorescence spectra were observed between the two states. Quinols 4 a-c and 5 a-c exhibited almost the same absorption and fluorescence spectra in solution; however, their solid-state fluorescence excitation and emission spectra in the crystalline state were quite different. We performed X-ray crystallographic analyses to elucidate the dramatic effect of the substituents of the nonconjugated linkage on the solid-state fluorescence excitation and emission spectra. The relationships between the solid-state photophysical properties and the chemical and crystal structures of 4 a-c and 5 a-c are discussed on the basis of the X-ray crystal structures.
A simple and selective synthetic method of quinolines and indoles by the reaction of β‐(2‐nitrophenyl)‐α,β‐unsaturated ketones with carbon monoxide was developed. When β‐(2‐nitrophenyl)‐α,β‐unsaturated ketones were allowed to react with carbon monoxide and water in the presence of a stoichiometric amount of sulfur or a catalytic amount of selenium, the corresponding quinolines were produced in moderate‐to‐good yields. On the other hand, in the absence of water, the indoles were produced by the selenium‐catalyzed reaction of the β‐(2‐nitrophenyl)‐α,β‐unsaturated ketones with carbon monoxide.
Heterocyclic fluorophores 5,5-dibutyl-9-dibutylamino-5H-benzo [b]naphtho[1,2-d]furan-6-one (4) and 3,3-dibutyl-9-dibutylamino-3H-benzo[kl]xanthen-2-one (7) with dialkyl substituents linked in a nonconjugated fashion to the chromophore skeleton have been derived from quinol-type compounds 1 and 2, and their photophysical properties were investigated in solution and in the solid state. Fluorophores 4 and 7 exhibit strong fluorescence intensity in the solid-state relative to that of quinols 1 and 2; however, 1 and 4 or 2 and 7 exhibit similar fluorescence intensities in solution. To elucidate the dramatic effect of the dialkyl substituent on the solid-state fluorescence excitation and emission spectra, we
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