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

Abstract

Abstract:Phosphole P oxide is a useful building block for π conjugated materials due to its nonaromatic and electron accepting character. We have synthesized a series of ring fused derivatives of phosphole P oxide based on the intramolecular nucleophilic cyclization of appropriate alkyne precursors or radical phosphanylations. Some of the thus obtained compounds exhibited intriguing uorescence properties and were applied to uorescence imaging. A donor acceptor type benzo [b]phosphole P oxide with a (diphenylamino)phenyl group exhibited large solvatochromism in its uorescence spectra, and could hence be used as a staining agent for lipid droplets. C Naphox and PB430, which consist of fully ring fused π conjugated ladder type scaffolds, exhibited outstanding photostability and their absorption and emission properties were suitable for super resolution STED imaging. Moreover, using PB430 conjugated antibodies, we carried out a 3 D reconstruction of the STED images and developed a photostability based multicolor STED imaging technique.

Negative fluorescence anisotropy of phosphole oxide-based dyes in nematic liquid crystals

“…The components of S TDM also suggest that CBF-S has lower anisotropy in its shape (low λ S and S LX~0 .23), which is the main reason for the low S TDM , similarly to the cases found on CP2 and CBM. Originally, the phenyl group attached to the phosphorus has been designed and required because of the synthetic reason, ie, availability of the starting materials and the stability toward the reaction conditions 39,47,48 . Here it is theoretically suggested that the structural nature, ie, >P(=O)Ph, also plays an important role in realising negative fluorescence anisotropy of phosphole oxide-based dyes in the present NLCs.…”

“…Five phosphole oxide-based fluorescent dyes (racemic mixtures)-(CP2), (CBM), (CBX), (CBF) and (CNX) (Fig. 2b)-were synthesised according to previously reported methods 39,[46][47][48] .…”

“…Here, with the aid of such theoretical analysis, we investigate steady-state fluorescence anisotropy of a series of phosphole oxidebased dyes 39,[46][47][48] in NLCs to clarify the relation between the experimentally observed negative anisotropy and the molecular structures. In addition, the theoretically derived general principle of the molecular design of dyes for controlling the fluorescence anisotropy and molecular alignment in NLCs, as well as conditions for realising strong negative anisotropy, is discussed.…”

Water‐Soluble Phospholo[3,2‐b]phosphole‐P,P′‐Dioxide‐Based Fluorescent Dyes with High Photostability

“…[18] Previously,w er eportedt he synthesis of as eries of phosphole-based p systems and studied their suitability for bioimaging by capitalizing on the electron-accepting character of the phosphole P-oxide. [19] By combining the electron-accepting benzophosphole P-oxide with an electron-donating triphenylamine moiety,w ed eveloped an environment-polarity-sensitive fluorescent probe,L ipiDye ( Figure 1a). [20] This donor-p-acceptor-type( D-p-A) probe exhibited high photostability, which was further increased by reinforcing the 2-arylbenzophosphole P-oxide skeleton with am ethylene bridge (C-Bphox;F igure 1a).…”

“…Previously, we reported the synthesis of a series of phosphole‐based π systems and studied their suitability for bioimaging by capitalizing on the electron‐accepting character of the phosphole P ‐oxide . By combining the electron‐accepting benzophosphole P ‐oxide with an electron‐donating triphenylamine moiety, we developed an environment‐polarity‐sensitive fluorescent probe, LipiDye (Figure a) .…”