Fluorescence and fluorescence imaging of two Schiff derivatives sensitive to Fe3+ induced by single- and two-photon excitation

Two new Schiff derivatives with N,N-bis(acetyloxyethyl) amino as end group have been synthesized and studied as possible fluorescence probe for Fe3+ detection. The single-photon and two-photon fluorescence properties of the dyes in the unbound state and in metal ions complexes were investigated. Some quantum yields and TPA cross sections at important points were calculated. At the same time, we investigated the stabilization of two complexes in appropriate time range and calculated the thermodynamic parameters of the complex at 298 K. The results showed that two compounds can be used as an efficient fluorescent probes for Fe3+ detection by single-photon excitation (SPE). And the process in forming complex was associated with releasing heat and changing degrees of freedom. Moreover, probe-1 is highly sensitive and selective to detect Fe3+ with two-photon active cross-section of 78 GM in Tris-HCl buffer solution at 800 nm. We proceeded to examine its potential utility for fluorescence imaging of Fe3+ in living cells. The results suggested that designing probe-1 can be used to detect intracellular Fe3+ by one and two-photon fluorescence imaging.