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Acidochromic Turn‐on 2,4‐Diarylpyrano[2, 3‐ b ]indole Luminophores with Solubilizing Groups for A Broad Range of Polarity
Author(s) -
Wilcke Tobias,
Glißmann Tobias,
Lerch Arne,
Karg Matthias,
Müller Thomas J. J.
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201802743
Subject(s) - chromophore , cycloisomerization , chemistry , indole test , solvent , turn (biochemistry) , aqueous solution , formylation , fluorescence , polarity (international relations) , photochemistry , polar , solubility , alkylation , stereochemistry , catalysis , organic chemistry , biochemistry , physics , quantum mechanics , astronomy , cell
Acidochromic turn‐on 2,4‐diarylpyrano[2, 3‐ b ]indole luminophores with different solubilizing groups are readily synthesized in a two‐step process, consisting of a Pd−Cu‐catalyzed domino insertion‐coupling‐cycloisomerization reaction of alkynoyl ortho ‐iodo anilides and terminal arylacetylenes furnishing the chromophore, and a desilylation‐alkylation sequence of the 2‐TMS‐ethylthio functionality for introducing solubilizing moieties, i. e. polar and aliphatic swallowtails as well as propylsulfonate potassium. These title compounds are able to cover a broad spectrum of solubility in nonpolar to polar and even aqueous solvent systems. Indeed, the turn‐on fluorescence can be shown to proceed without precipitation in aqueous solvent systems. In addition, a selected pyrano[2, 3‐ b ]indole forms clusters of 127 nm diameter at high water concentrations as determined by dynamic light scattering.