Installation of a carbanionic substituent, that is strongly stabilized by two (trifluoromethyl)sulfonyl (Tf = SO 2 CF 3) groups, into several fluorescence dyes including boron-dipyrromethenes (BODIPYs), fluoresceins, and aminocoumarins has been achieved by the 2,2-bis(triflyl)ethylation reaction of the dye frameworks with highly electrophilic Tf 2 C = CH 2 , followed by neutralization with NaHCO 3. Despite the contradiction between water solubility and lipophilicity, the carbanion-decorated dyes thus obtained showed significant enhancement of not only water solubility but also lipophilicity. This work clearly demonstrates that the fluorinated, highly stabilized carbanionic substituent is a new option for controlling the macroscopic property of chemical materials. Water solubility (and aqueous solubility) is a key macroscopic property for chemical materials directed towards biorelevant applications. [1] The most common way to improve the water solubility of less soluble compounds is introduction of ionic groups such as the sulfonato group into the molecular structure (Figure 1 A). However, such ionic functionalities
The carboarylation reaction of biphenyl-alkynes was successfully triggered by electrophilic attack of 1,1-bis (triflyl)ethylene on the alkyne moiety to give polycyclic aromatic hydrocarbons (PAHs) decorated by superacidic carbon acid functionality. Neutralisation of thus obtained acids with NaHCO 3 yielded the corresponding sodium salts, which showed improved solubility in both aqueous and organic solvents.Polycyclic aromatic hydrocarbons (PAHs) are fragment structures of carbon materials exemplified by fullerenes, carbon nanotubes, and nanographenes. [1] Such extended π-conjugate systems have drawn considerable interest because of their characteristic photophysical and electronical properties. [2] The polycyclic aromatic skeletons are also found in structures of biologically active agents including DNA intercalators, [3] HIV integrase inhibitors [4] and some phenanthrene alkaloids. [5] For these reasons, a variety of synthetic methodologies for constructing the PAH frameworks have been developed. [6] In particular, the ring-closing reactions of biaryl-alkynes using several electrophilic species including Brønsted acid, [7] halonium equivalents, [8] and transition metal catalysts [9] have been successfully utilised into the regioselective formation of the PAHs. However, a significant drawback for exploring further applications is low solubility of some PAHs in both organic and aqueous solvents. [10] Recently, we reported the functionalisation of borondipyrromethene (BODIPY) fluorescent dyes by a highly stabi- [a]
A metal- and irradiation-free preparation of Tf2CHCH2-decorated carbazoles from 1-(indol-2-yl)but-3-yn-1-ols under mild conditions with a 2-fluoropyridinium salt as the Tf2CCH2 source has been attained in a straightforward and selective manner.
Installation of a carbanionic substituent, that is strongly stabilized by two (trifluoromethyl)sulfonyl (Tf = SO 2 CF 3) groups, into several fluorescence dyes including boron-dipyrromethenes (BODIPYs), fluoresceins, and aminocoumarins has been achieved by the 2,2-bis(triflyl)ethylation reaction of the dye frameworks with highly electrophilic Tf 2 C = CH 2 , followed by neutralization with NaHCO 3. Despite the contradiction between water solubility and lipophilicity, the carbanion-decorated dyes thus obtained showed significant enhancement of not only water solubility but also lipophilicity. This work clearly demonstrates that the fluorinated, highly stabilized carbanionic substituent is a new option for controlling the macroscopic property of chemical materials. Water solubility (and aqueous solubility) is a key macroscopic property for chemical materials directed towards biorelevant applications. [1] The most common way to improve the water solubility of less soluble compounds is introduction of ionic groups such as the sulfonato group into the molecular structure (Figure 1 A). However, such ionic functionalities
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