Truxene-cored π-expanded triarylborane dyes as single- and two-photon fluorescent probes for fluoride.
Fluoride anion (F(-)) significantly affects chemical, biological, and environmental processes. Fluoride recognition and detection have received increasing attention. Convenient, effective, and sensitive fluorescent probes for F(-) should urgently be designed and synthesized. In this study, we describe a strategy for constructing two triarylborane-based fluoride fluorescent probes: 2,7,12-tri(2-(5-(dimesitylboryl)thiophen-2-yl)ethynyl)-5,5',10,10',15,15'-hexaethyltruxene (C3B3) with π-3A (acceptor) configuration and 2,7-di(N,N-diphenylamino)-12-(5-(dimesitylboryl)thiophen-2-yl)-5,5',10,10',15,15'-hexaethyltruxene (N2SB) with 2D (donor)-π-A configuration. The loss of color of the tetrahydrofuran solution of these probes from greenish yellow suggests that they can conveniently monitor F(-) at a low concentration (10 μM) free of apparatus. The different structural features of these probes varied their fluorescent responses to F(-). The single-photon fluorescence intensity of C3B3 declined to 90% upon the addition of 4.5 equivalents of F(-) to its tetrahydrofuran solution. However, the single-photon fluorescence intensity of N2SB was enhanced six-fold upon addition of 2.5 equivalents of the F(-). Under the experimental conditions, the detection limits of the two probes for F(-) can reach 12-13 μM (C3B3) and 3-5 μM (N2SB). The ability of the two probes in detecting F(-) in their toluene solutions in the two-photon mode was also investigated. The sensitive two-photon fluorescence responses of both probes make them excellent two-photon fluorescence probes.
College of Science, Northwest A&F University, Yangling 712100, P.R. China. jywang@nwsuaf.edu.cn.
Mao-Sen
MS
Yuan
Qi
Q
Wang
Wenji
W
Wang
Dong-En
DE
Wang
Junru
J
Wang
Jinyi
J
Wang
D001880:Boranes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D005459:Fluorides / Q000032:analysis*; D057230:Limit of Detection; D008958:Models, Molecular; D013050:Spectrometry, Fluorescence / Q000379:methods
D001880:Boranes; D005456:Fluorescent Dyes; D005459:Fluorides