Amide‐Triazolium‐Appended Anthracenes for Turn‐On Fluorescence Sensing of Anions in Noncompetitive and Competitive Solvents

Abstract

A new anthracene‐based receptor bearing two arms of amide‐triazolium anion‐binding sites, and its counterpart compound with one amide‐triazolium arm, have been synthesized and characterized. Their ability to bind anions in different solvents (CH3CN, CHCl3 and DMSO) has been investigated in detail by using fluorescence techniques. Both compounds exhibited significant fluorescence turn‐on sensing of F− and H2PO4− ions in noncompetitive and competitive environments with different binding modes. In CH3CN and CHCl3, the receptor with two triazoliums binds H2PO4− in 1:1 and 1:2 host–guest complexes, showing anthracene‐based excimer emission in the 1:1 complex, and strong monomer emission in the 1:2 complex. In DMSO, only the 1:1 stoichiometric complex was detected. In contrast, it binds with F− and AcO− with 1:2 stoichiometry both in noncompetitive and competitive solvents. The anion‐binding mechanism of both compounds was also evaluated by 1H NMR spectrometric titration and density functional theory calculation.

Ferrocene-containing macrocyclic triazoles for the electrochemical sensing of dihydrogen phosphate anion

“…The resulting 1,2,3-triazole ring has a substantial 5D dipole along the C-H bond that creates an effective C-HÁ Á Áanions hydrogen bonding, which could further be enhanced by converting the triazole unit into a triazolium cation [20,21]. Some triazole-based receptors such as macrocycles [22][23][24], foldamers [25][26][27] and short flexible oligomers [28][29][30], have particularly higher affinities and selectivities towards chloride anions. Other 1,2,3-triazole-linked dendrimers and polymers for various phosphates recognition properties have also been reported [31][32][33].…”

Solvent Acts as the Referee in a Match‐Up Between Charged and Preorganized Receptors

“…Lower polarity solvents were not investigated, presumably due to the breakdown in these assumptions. A few other studies have emerged [17b,18,19] that have measured anion binding to charged receptors across various solvents. Studies on dicationic receptors [20] by Pandey included chloroform but the impact of ion pairing was not addressed.…”

Fluorescent triazolium for sensing fluoride anions in semi-aqueous solution

“…[41][42][43] Several groups, including ours, have used triazolium as a platform for anions recognition. [44][45][46][47][48][49][50][51] Thus, a series of triazolium-based probe for uorescence sensing of F À , H 2 PO 4…”