Investigation on structurally different Cu(II) and Ni(II) complexes constructed from a novel pyridine-terminal salamo-like ligand

Metal-organic frameworks doped with metal ions for efficient sterilization: Enhanced photocatalytic activity and photothermal effect

Photocatalytic and photothermal disinfection is a promising strategy for addressing the challenges of environmental microbial contamination. In this work, we choose a metal-organic framework (MOF), ZIF-8, as an inexpensive and ideal model for metal ion doping, and manipulate the band structure, thermal vibration in molecules, charge distribution, and robustness of the metal-ligand coordination bond of the metal-ion-doped ZIFs for their use in photo-disinfection. The effects of their absorption edge, rate of the photo-induced temperature rise, transient photocurrent response, photo-generated reactive oxygen species (ROS) type, and crystal stability on the photo-disinfection performance are systematically studied by varying the metal ion type (Co²⁺, Ni²⁺, or Cu²⁺) and doping concentration (1-100%). The results show that the efficiency of light harvesting and photogenerated carrier separation is facilitated in all doped ZIFs. The photothermal conversion gradually improves with the increasing concentration of doped Co²⁺/Cu²⁺. Remarkably, the photo-generated ROS type changes from the original singlet oxygen (¹O₂) to multiple ROS (¹O₂ and •O₂^-) due to the introduction of Co(II) sites. Consequently, compared with pristine ZIF-8 and other doped ZIFs, Co²⁺-doped ZIF-8 with a 5% doping concentration shows the highest sterilization efficiency (6.6 log₁₀ CFU mL^-1) against Escherichia coli (E. coli) under simulated sunlight within one hour by virtue of the enhanced photothermal effect and the generation of multiple ROS. This work provides insights into the application of metal-ion-doped MOF photocatalysts to the disinfection of environments with pathogenic microorganisms.

A highly selective and sensitive salamo-salen-salamo hybrid fluorometic chemosensor for identification of Zn2+ and the continuous recognition of phosphate anions

A salamo-salen-salamo hybrid fluorescent chemical sensor (H₄L) was synthesized and characterized. It exhibits high selectivity and sensitivity to Zn²⁺ in physiological pH range. Meanwhile, its zinc(II) complex (L-Zn²⁺) continuously responses phosphate anions in DMF/H₂O (v/v, 9:1) solution. Moreover, the identification processes are explored using characterization methods such as UV-absorption spectra, IR spectra and ESI-MS spectrum. In addition, the coordination mechanism of H₂PO₄^- and Zn²⁺ were successfully exploited to make the chemical sensor reproducible. In short, the sensors H₄L and L-Zn²⁺ will be promising detection devices for Zn²⁺ and phosphate anions.

A novel bifunctional-group salamo-like multi-purpose dye probe based on ESIPT and RAHB effect: Distinction of cyanide and hydrazine through optical signal differential protocol

A novel bifunctional-group multi-purpose dye probe p-TNS has been designed and synthesized. The probe p-TNS has unique excited-state intramolecular proton transfer (ESIPT) and resonance-assisted hydrogen bonding (RAHB) coupled system, was confirmed to detect cyanide and hydrazine by blocking the ESIPT effect. Cyanide can change the fluorescence of the solution from bright green to orange-red (116 nm Stokes shift), while hydrazine causes the bright green fluorescence to be quenched. The recognition mechanism of the probe p-TNS to CN^- and N₂H₄ was proposed reasonably through spectral characterizations and theoretical calculations. Combined with theoretical calculations, it was speculated that the solvent dependence may be caused by the ICT effect in the molecule. The probe p-TNS could be prepared into test strips for the detection of cyanide and hydrazine. In addition, the probe molecule can also be used to detect trace amounts of cyanide in agricultural products, and respond to gaseous hydrazine by direct contact, indicating that the probe p-TNS has good practical application prospects. Therefore, this molecular framework provides a new way of thinking about detecting multiple target substances.