Transition metal complexes constructed by pyridine–amino acid: fluorescence sensing and catalytic properties

Abstract

Four amino acid Schiff base complexes—one with a 3D network structure ({[Cd2(PYSA)2(H2O)]·3H2O}n (1)) and the other three with a supramolecular network structure {[Co(PYSA) (H2O)2]·H2O}n (2), {([Zn(PYSA)(H2O)2]·H2O}n (3), {[Mn(PYSA)(H2O)2]·H2O}n (4)), (PYSA = (S-2-(pyridine-4-ylmethylamino) succinic acid)—were successfully obtained under hydrothermal conditions. Among the four complexes, photoluminescence analysis revealed that complex 1 exhibited high selectivity and sensitivity in the detection of iron ions. In particular, it was able to qualitatively and quantitatively detect iron ions at low concentrations without interference from other ions. With a Fe3+ concentration of 0.01 mol/L, the detection limit was 0.81 μM, Ksv = 2.46 × 104 L/mol. In addition, complex 2 exhibited excellent catalytic performance toward 4-nitrophenol (4-PNP). Four amino acid Schiff base complexes 1–4 were synthesized by a hydrothermal method. Among the four, complex 1 exhibited good fluorescence sensing performance in the detection of Fe3+ in water. In addition, the catalytic activity of complex 2 for 4-PNP was preliminarily investigated, which showed an ability to reduce 4-PNP to 4-PAP.