Jun Feng Zhang

Fluorescence and Colorimetric Chemosensors for Fluoride-Ion Detection

Detection Ying Zhou,†,‡ Jun Feng Zhang, and Juyoung Yoon*,† †Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea ‡Key Laboratory of Medicinal Chemistry for Natural Resource, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, P. R. China

Naphthalimide modified rhodamine derivative: ratiometric and selective fluorescent sensor for Cu2+ based on two different approaches.

A new rhodamine-based derivative bearing a 1,8-naphthalimide group (1) was synthesized as a dual-mode Cu(2+)-selective sensor via the rhodamine ring-opening approach and ratiometric displacement. A colorimetric and off-on signal for Cu(2+) through rhodamine ring opening in 1 and ratiometric fluorescent signal output when Cu(2+) displaces the bound Zn(2+) in the 1-Zn(2+) complex can be observed.

A highly selective colorimetric and ratiometric two-photon fluorescent probe for fluoride ion detection.

A naphthalimide-based highly selective colorimetric and ratiometric fluorescent probe for the fluoride ion displayed both one- and two-photon ratiometric changes. Upon reaction with the F(-) (TBA(+) and Na(+) salts) anion in CH(3)CN as well as in aqueous buffer solution, probe 1 shows dramatic color changes from colorless to jade-green and remarkable ratiometric fluorescence enhancements signals. These properties are mechanistically ascribed to a fluoride-triggered Si-O bond cleavage that resulted in a green fluorescent 4-amino-1,8-naphthalimide.

Pyrene Excimer-Based Calix[4]arene FRET Chemosensor for Mercury(II)

A novel calix[4]arene derivative locked in the 1,3-alternate conformation (2) bearing two pyrene and rhodamine fluorophores was synthesized as a selective sensor for the Hg(2+) ion. The sensoring is based on FRET from pyrene excimer emissions to ring-opened rhodamine absorption upon complexation of the Hg(2+) ion. Addition of Hg(2+) to a mixed solution of 2 gave significantly enhanced fluorescence at ∼576 nm via FRET with excitation at 343 nm. We also found that the pyrene excimer emissions formed by the intramolecular π-π interactions are more effective in obtaining strong FRET bands than those by intermolecular π-π interactions.

A two-photon excited luminescence of water-soluble rhodamine-platinum(II) complex: fluorescent probe specific for Hg2+ detection in live cell.

The first example of cyclometalated platinum(II)-containing rhodamine probe (1) with two-photon induced luminescent properties was synthesized and investigated for mercury detection. A highly selective color change of 1, from light yellow to pink, is observed only in the presence of Hg(2+) due to the formation of 1,3,4-oxadiazole ring in 2. This selectivity of Hg(2+) with color changes can be observed easily by the naked-eye. Meanwhile, a remarkable turn-on and selective 20-fold fluorescent enhancement of 1 upon binding with Hg(2+) over the other tested metal ions was observed. The water-soluble probe 1 was successfully applied in the visualizing of the site of Hg(2+) accumulation as well as estimating of trace amounts of mercury ions in live HeLa cells by two-photon microscopy.

A pellet-type optical nanomaterial of silica-based naphthalimide–DPA–Cu(II) complexes: recyclable fluorescence detection of pyrophosphate

A pellet-type nanomaterial prepared from a mesoporous silica-immobilized naphthalimide-DPA-Cu(II) complex (MSIND-Cu) is investigated as a selective fluorescent chemosensor for PPi detection with a large off-on fluorescence change, low detection limit, short response time and a broad pH test range.

Phosphate ion targeted colorimetric and fluorescent probe and its use to monitor endogeneous phosphate ion in a hemichannel-closed cell.

Fluorescent probe 1, the first inorganic phosphate (Pi) targeted colorimetric and fluorescent probe to detect endogenous Pi in hemichannel-closed cells, has been developed. Probe 1 undergoes a unique Pi induced hydrolytic reaction in DMSO-HEPES (V/V = 9:1) buffered (0.02 M, pH 7.4) solutions that produces a colorimetric change associated with a 62 nm red-shift in the UV-vis absorption maximum and up to a 780-fold enhancement in the fluorescence intensity. The mechanistic proposal that these spectroscopic changes are associated with reaction Pi with 1 to form coumarin gains support from the results of theoretical calculations and mass spectrometry studies. Observations made in fluorescence imaging studies with HeLa cells and C. elegans show that 1 can be employed to monitor Pi production in vivo caused by apyrase-catalyzed ATP hydrolysis. Moreover, probe 1 was utilized to show that apoptosis of hemichannel-closed Sf9 cells is caused by Inx3 promoted dephosphorylation of Akt (RAC serine/threonine-protein kinase), leading to an elevation of the concentration of Pi. Overall, the study has produced the first fluorescent sensor 1 for endogenous inorganic phosphate. Moreover, the utility of 1 for measuring Pi release in vitro has been demonstrated and utilized to elucidate the mechanism of Inx3 action in hemichannel-closed Sf9 cells.