A single-armed salamo-based fluorescence sensor QANS was designed and synthesized. QANS exhibited aggregation-induced emission (AIE) property in a binary solvent mixture (DMF/H2O) as the water content increased, and the QANS powder showed strong orange-yellow emission in solid state. In addition to the intriguing AIE characteristic, QANS demonstrated high selectivity and sensitivity for Al3+ over various metal ions through a “turn-on” fluorescence response. A plausible mechanism for the interaction of sensor QANS with Al3+ was proposed according to the ESI-MS, Job’s plot, 1H NMR titration analysis and DFT calculations. Furthermore, the sensor QANS was applied in monitoring Al3+ in actual water samples. To further determine its applicability, the convenient paper strips of QANS were applied for selective monitoring of Al3+ ions. 

A new single-armed salamo-based sensor with aggregation-induced emission characteristic for selective sensing of aluminium ions

Abstract A symmetrical N2O2-tetradentate dioxime chemical sensor H2L was synthesized for the first time. The sensor H2L can identify S2– ion with dual channels of fluorescence–ultraviolet spectra, and through the calculation of binding constant and detection limit of L-S system, it was showed that H2L can detect S2– ion with high efficiency and specificity. pH response experiments were carried out on L-S system and H2L to explore the pH range recognized by them. The recognition mechanism was determined by 1H NMR titration experiment. At the same time, a new method of macro recognition by means of naked eye recognition (under natural light and ultraviolet light of 365 nm) and filter paper recognition was developed. The practical application of the sensor H2L to detect H2S was evaluated in actual water samples and identification experiment of H2S. GRAPHICAL ABSTRACT

A N2O2-tetradentate dioxime fluorescence probe for highly efficient sensing of S2– and solution discoloration detection of H2S gas

Experimental and theoretical investigation of a new non-symmetric salamo-like ligand and its tri-nuclear Zn(II) and Ni(II) complexes

Studies on two phenoxo-bridged homopolynuclear Cu(II) bis(salamo) type complexes based on theoretical calculations and fluorescence properties

Two helical centrosymmetric homotetranuclear Cu (II) complexes, [Cu4(L)2(EtOH)2](ClO4)2·2EtOH·2CHCl3 (1) and [{Cu4(L)2(EtOH)2}{Cu4(L)2(HNO3)2}](NO3)4·3EtOH·3MeOH (2), were synthesized by the reactions of a symmetric bis (salamo)-based ligand H3L with Cu(ClO)2·6H2O and Cu(NO)3·3H2O, respectively, and certified by elemental analyses, UV–Visible absorption spectra, infrared spectra and single-crystal X-ray analysis techniques. X-ray crystal structure analyses reveal that four Cu (II) atoms of complex 1 are attached to two deprotonated ligand (L)3− units with the help of two coordinated ethanol molecules, and then forming a helical centrosymmetric complex by H-bonding and π⋯π interactions. While complex 2 unit cell contains two crystallographically independent but chemically identical homotetranuclear complexes (molecules A and B), eight Cu (II) atoms are coordinated by four deprotonated ligand (L)3− units. The coordination mode of four Cu (II) atoms from molecule A is the same as complex 1; at the same time, oxygen atoms on nitrates are involved in the coordination of another four Cu (II) atoms from molecule B. The short-range interactions in complexes 1 and 2 were calculated by Hirshfeld surfaces analyses. The molecular orbital energy levels, molecular stabilities of complexes 1 and 2 were analyzed by DFT calculations. In addition, antibacterial assays were also investigated in detail. 

Exploring two helical centrosymmetric homotetranuclear Cu (II) bis (salamo)‐based complexes

A unitary fluorescence probe to sense Co2+: Validated by theoretical studies and X-ray crystallography

A new salamo-type bisoxime compound H3L has been synthesized and exploited as a highly efficient chemosensor with multiple responses to Cu2+ and S2−. Chemosensor H3L exhibits highly selective and sensitive detection of Cu2+ and S2− simultaneously. The LODs of Cu2+ and S2− were calculated to be 1.5398 × 10−7 and 1.7274 × 10−7 M in DMF-water (9 : 1, v/v) solution, respectively. The color of the chemosensor H3L solution changed from light green to dark green after adding S2− under a 365 nm UV-lamp. The sensing mechanism of the chemosensor H3L was characterized using several methods, including ultraviolet spectroscopy, ESI-mass spectrometry, 1H-NMR and FT-IR spectroscopy. Meanwhile, the crystal structure of the Cu(II) complex, [Cu2(L)]ClO4·2CH3OH, has been determined by X-ray crystallographic analysis. Density Functional Theory (DFT) was employed to further understand the obtained experimental results.

Hui Liu

Papers

A unitary fluorescence probe to sense Co2+: Validated by theoretical studies and X-ray crystallography

A highly efficient yet stable salamo-type fluorescent chemosensor with multiple responses to Cu2+ and S2−