A highly sensitive and efficient fluorescence-ultraviolet dual channel chemical sensor H₂L based on the salamo-like bisoxime (6,6′-dimethoxy-2, 2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol) was synthesized, Cu²⁺ and S²⁻ ions can be detected respectively. For the identification of metal cations, the Cu²⁺ can quench the fluorescence intensity of probe H₂L at the excitation wavelength of 311 nm, and when the same equivalent of EDTA was added, the fluorescence intensity of L-Cu complex returned to its original intensity practically, completing the fluorescence “OFF-ON-OFF” cycle after adding the same amount of Cu²⁺ again. The mechanism was confirmed by high resolution mass spectrometry, and it was concluded that the probe H₂L and Cu²⁺ formed a complex. For the identification of anions, UV–Vis spectral identification and naked-eye recognition for S²⁻ were performed. The binding mode of the probe to the sulfur anion and the recognition mechanism were confirmed by ¹H NMR titration. In addition, the probe H₂L showed high selectivity and sensitivity to Cu²⁺ and S²⁻, the detection limits of L-Cu and L-S systems toward Cu²⁺ and S²⁻ are 46 and 25 nM respectively. In terms of application, the content of Cu²⁺and S²⁻ in different water samples (distilled water, Yellow River water and tap water) with probe H₂L was successfully tested. These results indicated that the probe H₂L can be used as a highly selective and sensitive dual channel sensor to detect both Cu²⁺ and S²⁻ ions in the environment and biological systems.

A novel, simple, highly selective, and sensitive fluorescence chemosensor for detecting Cd²⁺ that was constructed from a bis(salamo)-type compound (H₄L) with two N₂O₂ chelating moieties as ionophore was successfully developed. Sensor H₄L could show fluorescence turn-on response rapidly and significant selectivity to Cd²⁺ over many other metallic ions (Cu²⁺, Ba²⁺, Ca²⁺, K⁺, Cr³⁺, Mn²⁺, Sr²⁺, Co²⁺, Na⁺, Li⁺, Ni²⁺, Ag⁺, and Zn²⁺), and a clear change in color from colorless to yellow that can be very easily observed via the naked eyes in the existence of Cd²⁺, while other metallic ions do not induce such a change. Interestingly, its fluorescent intensity was increased sharply with the increased concentration of Cd²⁺. The detection limit of sensor H₄L towards Cd²⁺ was down to 8.61 × 10⁻⁷ M.

A heterobimetallic 3d–4f complex [Cu(L)Dy(NO₃)₃] based on a symmetric salamo-like ligand (H₂L) was synthesized and characterized by elemental analyses, IR, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The complex crystallized in the monoclinic, space group P 2₁/c, included one tetra-coordinated Cu(II) atom (Cu1), one deca-coordinated Dy(III) atom (Dy1), one completely deprotonated (L)²⁻ unit, and three nitrate groups involved in coordination. Cu1 adopted a planar quadrilateral configuration, and Dy1 formed a slightly distorted double-cap square antiprism geometry. The complex finally formed an infinite 2D and 3D supramolecular structure via the intermolecular hydrogen bonds and π–π interactions. Due to the paramagnetism of Cu²⁺ ions, the complex showed fluorescence quenching. The electronic structure and stability of the complex were proved by density functional theory (DFT) calculation.

A new tetranuclear zinc(II) complex with an asymmetrical Salamo-type chelating ligand, H₃L (5-methoxy-6′-hydroxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol), was synthesized and characterized using FT-IR, elemental analyses, X-ray single crystal diffraction method, UV-Vis, and fluorescence spectra. The zinc(II) complex possesses the cell parameters a = 8.1960(7) Å, b = 9.8127(8) Å, c = 16.5428(15) Å, Z = 1, V = 1172.5(2) ų, R₁ = 0.0722, and wR₂ = 0.1558, and crystallizes in the triclinic system, with space group P-1. X-ray crystal structure analysis reveals that Zn1 and Zn2 atoms are all pentacoordinated and adopt slightly twisted tetragonal pyramidal and trigonal bipyramidal geometries. The zinc(II) complex forms a 1D supramolecular chain via intermolecular hydrogen bonds along the b axis. Besides, the fluorescence properties have been discussed.

A newly designed Co(II) complex, [Co₃(L)(OAc)₂(CH₃OH)₂]·CH₃OH, by the reaction of a bis(salamo)-type tetraoxime ligand (H₄L) with Co(II) acetate tetrahydrate was synthesized and characterized by elemental analyses, IR, UV-vis spectra and single-crystal X-ray crystallography. The UV-vis titration experiment manifested that a trinuclear (L:M = 1:3) complex was formed. It is worth noting that the two terminal Co(II) (Co1 and Co3) atoms of the Co(II) complex have different coordination modes and geometries unreported earlier. Furthermore, through intermolecular interactions (C–H···O, C–H···π and O–H···O), a 2D layer-like network is constructed. In addition, the fluorescence behaviors, antimicrobial activities and electrochemical properties of H₄L and its Co(II) complex were investigated.

Two newly designed complexes, [Zn(L¹)(EtOH)] (1) and [{Zn(L²)(OAc)₂}₂Zn]·CHCl₃ (2) derived from salamo and half-salamo chelating ligands (H₂L¹ and HL²) have been synthesized and characterized by elemental analyses, IR and UV-VIS spectra, fluorescence spectra, and X-ray crystallography. Complex 1 shows a slightly distorted tetragonal pyramid and forms an infinite 3D supramolecular structure. All of the Zn(II) ions in complex 2 are hexa-coordinated with slightly distorted octahedral geometries. Complex 2 possesses an infinite 2D space structure. The fluorescence titration experiments were used to characterize fluorescence properties of complexes 1 and 2. And the normalized fluorescent spectra exhibit that complexes 1 and 2 have favourable fluorescent emissions in different solvents.