A depropargylation-triggered fluorescence "turn-on" probe for the detection of Pd2+ based on a bispropargylamine-rhodamine conjugate.
A bis-propargyl-appended rhodamine B-based receptor BPRB has been synthesised that exhibits pronounced fluorescence enhancement in the presence of Pd2+ ions. The addition of Pd2+ enhanced the fluorescence intensity of BPRB by 113-fold (Φf = 0.37) and BPRB was found to exhibit high selectivity towards Pd2+ compared to a range of other metal ions. The enhancement of fluorescence was triggered by spirolactam ring opening followed by depropargylation of BPRB in the presence of Pd2+, as evidenced by FTIR and NMR analyses. BPRB was able to detect Pd0 without the addition of a reducing agent, and the emission intensity of BPRB–Pd0 was almost identical to that of BPRB–Pd2+; however, a rapid fluorescence response was observed in the presence of PPh3. To explore the efficiency of the rhodamine unit, a bispropargyl derivative of cyclohexane (BPCH) was synthesised and the fluorescence response towards Pd2+ was examined and compared with BPRB, revealing that the rhodamine unit enhanced the fluorescence intensity by 500-fold. The fluorescence images of BPRB and BPRB–Pd2+ samples indicate that BPRB could be useful for imaging Pd2+ in living cells.
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China.
Rathinam
R
Balamurugan
Chih-Chieh
CC
Chien
Kai-Ming
KM
Wu
Yi-Hong
YH
Chiu
Jui-Hsiang
JH
Liu
D002413:Cations, Divalent / Q000032:analysis; D005456:Fluorescent Dyes / Q000737:chemistry*; D061848:Optical Imaging / Q000379:methods; D010165:Palladium / Q000032:analysis*; D010293:Pargyline / Q000031:analogs & derivatives* / Q000737:chemistry; D011437:Propylamines / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
D002413:Cations, Divalent; D005456:Fluorescent Dyes; D011437:Propylamines; D012235:Rhodamines; C009054:propargylamine; D010165:Palladium; D010293:Pargyline