A series of trinuclear zinc(ii) complexes with reduced Schiff base ligands: turn-off fluorescent chemosensors with high selectivity for nitroaromatics

Abstract

A facile method for synthesizing trinuclear zinc(II) complexes with compartmental reduced Schiff bases has been described. Five such complexes, [{(N₃)Zn(L¹)}₂Zn] (1), [{(SCN)Zn(L¹)}₂Zn] (2), [{(SCN)Zn(L²)}₂Zn] (3), [{(N₃)Zn(L²)}₂Zn] (4) and [{(N₃)Zn(L³)}₂Zn]·CH₂CL₂ (5) where H₂L¹ = 2,2′-[(1,3-propanediyl)bis(iminomethylene)]bis[6-ethoxyphenol], H₂L² = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)]bis[6-methoxyphenol] and H₂L³ = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)]bis[6-ethoxyphenol], were synthesized and characterized by elemental and spectral analyses. X-ray crystallographic analyses have confirmed their structures. All complexes may be used as sensors for the detection of nitroaromatics in DMF via turn-off fluorescence response.