A new cinnamaldehyde-rhodamine based dual chemosensor for Cu2+and Fe3+and its applicability in live cell imaging

A new fluorescent sensor, RT4 has been synthesized by reacting trans-4-(diethylamino)cinnamaldehyde with rhodamine B hydrazide in a one-step reaction. The characterization of RT4 was done by using FT-IR, 1H NMR, 13C NMR, and single crystal X-ray crystallography. In aqueous acetonitrile (1:1, v/v pH 7.5), RT4 exhibited a highly selective and sensitive colorimetric response upon recognition of Cu2+ and fluorometric response with Fe3+ ions. The calculated limit of detections (LOD) of RT4 with Cu2+ and Fe3+ were 0.20 and 0.18 mu M at lambda abs/em = 555 and 585 nm, respectively. Test strips for colorimetric detection of Cu2+ and Fe3+ as an on-site test kit were successfully prepared. Furthermore, the MTT assay indicated that RT4 possess low cytotoxicity in human colorectal carcinoma HCT 116 after 24 h. The fluorescence microscopy experiment suggested that RT4 could also serve as a biological fluorescence probe for the detection of Fe3+in HCT 116 cells.