X-ray structure of two Schiff bases: TURN-ON sensing of Fe3+ and Al3+ insight the HepG2 cell line
The efficiency of fluorescence sensitivity of a sensor may be tuned by modulation of steric and electronic parameters in the structure. In this work a thiophenyl Schiff base, (E)-N1-(phenyl(pyridin-2-yl)methyl)-N2-(thiophen-2-ylmethylene)benzene-1,2-diamine (HL') exhibitions very high selectivity and sensitive fluorescence enhancement to Fe3+ with violet emission (λem, 385 nm; LOD, 3.8 nM). On the other hand the naphthyl Schiff base, (E)-1-(((2-((phenyl(pyridin-2-yl)methyl)amino)phenyl)imino)methyl)naphthalen-2-ol (H2L") exhibits fluorescence sensitivity towards Al3+ showing blue emission (λem, 502 nm; LOD, 3.3 nM) in H2O (HEPES buffer, pH 7.4) medium. The emission enhancement upon binding to Fe3+ to HL' may be considered by the restriction of intramolecular rotation while probe H2L" selects Al3+ showing turn on emission through restriction of ESIPT and introduction of CHEF. Furthermore, DFT computation supports the sensing strategy and the probes have been applied for intracellular detection of Fe3+ and Al3+ in HepG2 cell lines.