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.

Two new dinuclear zinc(II) complexes, [Zn₂(µ_1,3-OAc)(L¹)₂]I·MeOH (1) and [Zn₂(µ_1,3-OAc)(L²)(NCS)] (2), (where HL¹ = 2-(((3-(dimethylamino)propyl)amino)methyl)-6-methoxy-phenol and H₂L² = 2,2′-[(1-Methyl-1,2-ethanediyl)bis(iminomethylene)]bis[6-ethoxyphenol]) have been synthesized and characterized by elemental and spectral analysis. Their X-ray solid state structures have been determined, revealing the existence of intramolecular Zn···O spodium bonds in both complexes due to the presence of methoxy (1) or ethoxy (2) substituents adjacent to the coordinated phenolic O-atom. These noncovalent interactions have been studied using density functional theory (DFT) calculations, the quantum theory of “atoms-in-molecules” and the noncovalent interaction plot. Moreover, a search in the Cambridge structure database (CSD) has been conducted in order to investigate the prevalence of intramolecular spodium bonds in Zn complexes. To our knowledge this is the first investigation dealing with intramolecular spodium bonds.

A unique penta-nuclear zinc(II) complex, [(μ_1,1-N₃)₂{(N₃)Zn(L)Zn}₂Zn(L)] {H₂L= 2,2′-[(1-methyl-1,2-ethanediyl)bis(iminomethylene)]bis[6-methoxyphenol]}, has been synthesized and characterized. X-ray crystallographic analysis has confirmed its structure. The complex has shown good phosphatase-mimicking activity {k_cat ∼ 398 h⁻¹ at 298 K}, evaluated spectrophotometrically by monitoring the increase in absorbance at ∼425 nm, indicating gradual release of p-nitrophenolate by the hydrolysis of 4-nitrophenylphosphate ester with time, when 4-NPP (disodium 4-nitrophenylphosphate hexahydrate) has been used as a substrate. The complex behaves as a sensor for the detection of nitroaromatics in DMF solution via turn-off fluorescence response. The solution phase sensing mechanism has been studied and a strong quenching efficiency has been found with a quenching constant (K_SV) of 6.497 × 10⁴ M⁻¹ for 3-methyl-4-nitrobenzoic acid.