Selective and Sensitive Two New Macroacyclic Schiff base Fluorescent Turn‐Off Receptors for Fe³⁺, DFT Calculation and Their Antibacterial Activity

Abstract

Two new Macroacyclic Schiff base chemosensors (L1 and L2) were synthesized by the one pot condensation reaction of 2‐[3‐(2‐formyl phenoxy)propoxy]benzaldehyde and aminophenol in a 1:2 molar ratio and were characterized by IR, NMR spectroscopy. Both Schiff bases displayed high selectivity and sensitivity towards Fe3+ over other metal ions in H2O‐DMF solution (Ag+,Cu2+, Ni2+, Zn2+, Mg+2, Mn+2, Pb+2, Co+2, Hg+2, Cr+3, Na+, Ba+2 and Cd2+) due to their structure including oxygen donor atoms. The test results showed fluorescence quenching of the fluorophores when Fe3+ was bound to the recognition units. From test results, a high selectivity for Fe3+ were discovered in this type of sensors, especially, the probe based on 2‐aminophenol exhibited more significant quenching in fluorescence intensity compared with 4‐aminophenol‐based due to its rigidity structure. In addition, the structure of ligands and their antibacterial properties was investigated.

New Schiff base salts as sources of blue and green light in the solid state: the role of the anion and protonation

“…Due to their fluorescent characteristics, Schiff bases find numerous applications, for instance in cellular bioimaging 24–27 and as organic light-emitting diodes (OLED), 28–32 selective sensors with high sensitivity for the determination of various cations, e.g. , Al 3+ , 33–35 Fe 3+ , 36–38 Ni 2+ (ref. 39–42) and pH indicators.…”

“…They may affect the spatial separation between the aromatic rings of the cationic Schiff base, possibly create additional molecular interactions, and influence the electron density of the fluorophore. [18][19][20][21][22][23] Due to their fluorescent characteristics, Schiff bases find numerous applications, for instance in cellular bioimaging [24][25][26][27] and as organic light-emitting diodes (OLED), [28][29][30][31][32] selective sensors with high sensitivity for the determination of various cations, e.g., Al 3+ , [33][34][35] Fe 3+ , [36][37][38] Ni 2+ (ref. [39][40][41][42] and pH indicators.…”

Synthesis and characterization of 1,3‐butadiene‐containing hyperbranched conjugated polymers as a selective chemosensors for Fe3+ ions

“…Currently, fluorescent chemosensors in mounting numbers are used for metal ion analysis and detection due to their indispensable role in chemical and biological processes. Small molecule fluorescent probes for detecting Fe 3+ based on fluorescein, [ 20–22 ] quantum dots, [ 23,24 ] rhodamine, [ 25 ] imine‐benzimidazole substances have successively been reported. [ 26–31 ] However, these methods suffer from a number of drawbacks: the probe can form redox‐active and potential toxic complexes with iron, and can also interact with other metal ions, leading to an interfering signal.…”