Late-stage functionalisation of alkyne-modified phospha-xanthene dyes: lysosomal imaging using an off–on–off type of pH probe

Abstract

A series of NIR-emissive phospha-xanthene dyes bearing an ethynyl group are reported. The late-stage functionalisation of the NIR dyes enables creation of multi-functionalised fluorescent probes that can be designed to target organelles of interest.

Silicon functionalization expands the repertoire of Si-rhodamine fluorescent probes

“…Modification of the bridging group as described herein is not possible with conventional oxygen-bridged xanthene dyes, but could be similarly applied to dyes with bridging elements such as carbon, germanium and phosphorus. 46 We anticipate that Si-modification will have broad applications within Si-xanthenes and spur the development of other classes of related dyes and functionalized materials.…”

“…S3 †). Notable examples include SiTMR (45) 5 and JF646 (46). 9 These dyes exist primarily in the spirolactone form in aqueous buffer, with K L-Z lactone-zwitterion equilibrium values 36 of 0.0034 and 0.002.…”

Xanthene dyes for cancer imaging and treatment: A material odyssey

“…The last work on phospha-rhodamines in 2021 was reported by Yamaguchi's group. [41] They synthesized a series of off-on-off type pH probes, including fluorescein, rhodamine, and rhodol cores functionalized with 2,6-dimethoxyphenyl at the 9-position bearing phenylphosphine oxide as the bridging moiety. For this series of NIR phospha-xanthene dyes, 4-ethynylphenyl group was installed on the phosphorous atom.…”

Fluorescent Benzothiadiazole Derivatives as Fluorescence Imaging Dyes: A Decade of New Generation Probes

“…Fluorescent small organic molecules are of paramount importance in the study of lysosomes and their dynamic processes. In this sense, several organic dyes have been used to stain lysosomes selectively [184–191] . Although the large number of fluorescent dyes applied to visualize lysosomes and their cellular events, up to now, only four fluorescent BTD derivatives (Figure 22) have been described as selective bioimaging probes to stain this specific organelle and all of them published very recently.…”