Beilstein J. Org. Chem.2019,15, 2133–2141, doi:10.3762/bjoc.15.210
functionalities were synthesized and their optical properties were studied. The sulfur functionalities were introduced by aromatic nucleophilic substitution of methoxy groups in triarylmethylium cations with ethanethiol followed by partial or full ring closure of the ortho positions with nitrogen or oxygen
of the ethylthiol substituents. For the triangulenium derivatives significant fluorescence was observed (Φf = 0.1 to Φf = 0.3).
Keywords: acridinium dyes; aromatic nucleophilic substitution; fluorescent dyes; sulfur-functionalized dyes; triangulenium dyes; triarylmethylium; Introduction
The design
-substituted triarylmethylium salts as simple precursors allowing both introduction of dialkylamino donor groups and formation of the heterocyclic triangulenium ring systems. These characteristic types of aromatic nucleophilic substitution (SNAr) reactions are exemplified by the synthesis of A3-ADOTA+ (Figure
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Graphical Abstract
Figure 1:
Structures of some representative triangulenium dyes. a) Rhodamine/fluorescine-like derivatives wit...
Beilstein J. Org. Chem.2019,15, 642–654, doi:10.3762/bjoc.15.60
(heteroaryl)methanes (Ar1Ar2Ar3)CH (Scheme 2). Formation of (Ar1Ar1Ar2)CH triads is a competing process, whose relative proportion varies depending on the choice of the substituents. The efficacy to perform these remarkable reactions in water as solvent, and to generate highly crowded triarylmethylium salts
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Graphical Abstract
Scheme 1:
Representative examples of tris(hetero/aryl)methanes, molecular hybrids and bis(indolyl)methanes wi...