Environment‐Sensitive Fluorescent Probe: A Benzophosphole Oxide with an Electron‐Donating Substituent

Abstract

Electron-donating aryl groups were attached to electron-accepting benzophosphole skeletons. Among several derivatives thus prepared, one benzophosphole oxide was particularly interesting, as it retained high fluorescence quantum yields even in polar and protic solvents. This phosphole-based compound exhibited a drastic color change of its fluorescence spectrum as a function of the solvent polarity, while the absorption spectra remained virtually unchanged. Capitalizing on these features, this phosphole-based compound was used to stain adipocytes, in which the polarity of subcellular compartments could then be discriminated on the basis of the color change of the fluorescence emission.

Phosphole <i>P</i>-Oxide-Containing π-Electron Materials: Synthesis and Applications in Fluorescence Imaging

“…Indeed, diphenylaminophenyl substituted benzo [b]phosphole P oxide 16 exhibited intriguing uorescence properties. 3 In toluene, 16 exhibited an absorption band with λ max 415 nm, while an intense uorescence band was observed at λ max 528 nm (Φ F 0.94). With increasing solvent polarity, the absorption spectra showed subtle changes (λ abs 403 420 nm), while the uorescence band was signicantly red shifted (DMSO: λ max 601 nm; EtOH: λ max 593 nm) (Figure 6).…”

“…This fact prompted us to examine the potential of 16 as a uorescence probe. 3 Fluorescence imaging of differentiated 3T3 L1 adipocytes with 16 was investigated using a confocal microscope equipped with a GaAsP multi channel spectral detector (Figure 9). When 3T3 L1 cells were incubated with 1 μM of 16 in Dulbecco s modi ed Eagle s medium (DMEM) for 2 h at 37 , a diffuse staining pattern with several bright spots appeared (0 day, column a), demonstrating that 16 is membrane permeable.…”

“…Therefore, phospholes exhibit a relatively low lying LUMO compared not only to pyrrole, but also to other heterole rings ( Figure 1). 3 Importantly, this characteristic feature is enhanced by the oxidation of the phosphorus atom to the phosphine oxide or sul de. Phosphole P oxides or P suldes are hence useful electron accepting moieties.…”

Stimuli-responsive chromism in organophosphorus chemistry

“…3). 14,15 Moreover, the hydroxy-substituted compound 10 deserves special mention, because it features not only strong solvatochromism, but also pronounced fluorescence in polar solvents. The reason can be found in its twisted structure in solution and that the lower energy excitation/emission can be attributed to a charge-transfer transition from the peripheral aromatic part to the diketophosphepin core.…”

Non-fused Phospholes as Fluorescent Probes for Imaging of Lipid Droplets in Living Cells

“…In these systems, the phosphole ring is fused with a phenyl- or naphtyl-ring. These types of probes have been used for imaging of HeLa cells, adipocytes, and preadipocytes (Wang et al, 2015; Yamaguchi et al, 2015). Herein, we synthesized a series of pyridyl- and thienyl-substituted phospholes (Scheme 1) and evaluated these compounds as fluorescent tools for fluorescent imaging of cells.…”