An AIE-active hemicyanine fluorogen with stimuli-responsive red/blue emission: extending the pH sensing range by "switch + knob" effect

Sijie Chen, Jianzhao Liu, Yang Liu, Huimin Su, Yuning Hong, Cathy K. W. Jim, Ryan T. K. Kwok, Na Zhao, Wei Qin, Jacky W. Y. Lam, Kam Sing Wong, Ben Zhong Tang
2012 Chemical Science  
Materials Solvents such as THF, chloroform, dichloromethane (DCM), and hexane were distilled under normal pressure under nitrogen immediately prior to use. Milli-Q water was used as deionized water. 4-Bromobenzaldehyde, tetrakis(triphenylphosphine)palladium(0), citric acid, and sodium hydrogen phosphate were purchased from Sigma-Adrich. Aniline was purchased from Int. Lab. All the chemicals were used as received without further purification. Compound 1 1 and 4 2 were prepared according to the
more » ... eviously published procedures. Buffer solutions with pH 113 were purchased from Merk, Riedel-de Haen and Sigma-Aldrich. Buffers with pH 5.107.13 were prepared by citric acid and sodium hydrogen phosphate 3 and confirmed by pH meter. The aqueous mixtures of TPE-Cy for pH-responsive UV and PL tests were prepared by adding an aliquot of DMSO stock solution into aqueous buffers with specific pH values. Instruments pH measurements were performed on a Beckman 340 pH/Temp meter. 1 H and 13 C NMR spectra were measured on a Bruker ARX 400 NMR spectrometer using CDCl 3 , DMSO-d 6 , or D 2 O as solvent and tetramethylsilane (TMS) as internal reference. UV absorption spectra were taken on a Milton Ray Spectronic 3000 array spectrophotometer. Photoluminescence (PL) spectra were recorded on a Perkin-Elmer LS 55 spectrofluorometer. Solid state quantum efficiency was measured using an integrating sphere at an excitation wavelength of 325 nm. High-resolution mass spectra (HRMS) were obtained on a GCT Premier CAB 048 mass Electronic Supplementary Material (ESI) for Chemical Science This journal is
doi:10.1039/c2sc01108e fatcat:ucbiyyb36vfkhexz2idvqnztt4