Far-red to NIR emitting xanthene-based fluorophores. (December 2022)

• Record Type: Journal Article
• Authors: Khan, Zeba; Sekar, Nagaiyan
• Is Part Of: Dyes and pigments. Volume 208(2023)
• Publication Date: 2022-12
• Subjects: Far-red -- NIR -- Near-infrared -- Element substitution strategy -- ᴨ-Extended O-xanthene -- Triangulenium ion -- Applications; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2022.110735
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Xanthene dyes are well known for their remarkable photophysical property, photostability, and ability to switch fluorescence on-off depending upon the external environment. Such intriguing traits find a wide number of applications, albeit their emission (≤600 nm) and stokes shifts (∼34 nm) limit their use in biological applications. A well-known approach to shifting the emission of xanthene dyes in the far-red to NIR is the element substitution strategy and extending ᴨ-conjugation in O-xanthene with carbon at the periphery. In this review, we have outlined the element substitution strategy, ᴨ-extended O-xanthene dyes with carbon at the periphery, and triangulenium ion. A section on general synthetic strategies, a detailed discussion of the substituent effect on the photophysical properties, and applications of far-red to NIR emitting xanthene dyes are included. A comparative study on the photophysical properties of (a) Si-rhodamine – amino Si-rhodamine, (b) Si-rhodamine – P-rhodamine, (c) P-rhodamine, P-fluorescein, and P-rhodol, (d) Te-rhodamine - Te=O rhodamine, and (e) crystal violet, rhodamine 3b, 2, 6, 10-tris(dialkylamino)trioxatriangulenium ions is discussed. This review highlights the structure-spectroscopic relationships, which will be useful in designing new far-red to NIR xanthene dyes. Highlights: Review on far-red to NIR emitting xanthene dyes. Element substitution strategy, ᴨ-extended O-xanthene dyes with carbon at the periphery, and triangulenium ion. Substituent effect on the photophysical property. Applications of far-red to NIR xanthene.