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

[Display omitted] • A new sensor, RT4 detecting Cu2+ and Fe3+ simultaneously with LOD values of 0.24 µM and 0.18 µM respectively. • MS, FTIR, 1H NMR spectra and DFT studies showing the possible binding mechanism of RT4 towards Cu2+ and Fe3+. • Inexpensive filter paper system was successfully prepared with RT4 as on-site assay kit. • Long-term MTT assay conducted showed low cytotoxicity of RT4 in living cells. • Cell imaging studies showed permeability of RT4 in detecting intracellular Fe3+. 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 µM at λ 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. [ABSTRACT FROM AUTHOR]