Silver(I) complexes containing bioactive salicylic acid derivatives: Synthesis, characterization, antibacterial activity, and their underlying mechanism

Article

作者: Zheng, Ren ; Wu, Chongyang ; Cai, Xinjun ; Shan, Yanni ; Guo, Suhang ; Luo, Jingming ; Fan, Xudong

Recognizing that silver-metallodrugs are a potential source of novel anti-infective therapeutic agents, this work adopts the complexation of biologically active salicylic acid derivatives with inherently antibacterial silver(I) ions as a strategy for developing new antibacterial agents. The synthesized silver(I) complexes were characterized by elemental analysis, spectroscopy, and X-ray diffraction analysis. The crystallographic results indicate that the silver(I) ion in complexes [Ag(imH)₂](SalH) (1) and [Ag(imH)₂](DiSalH)·H₂O (2) only coordinates with the imidazole nitrogen atom, while the 4-aminosalicylic acid in complex [Ag(imH)₂(AmSalH)]·H₂O (3) additionally coordinate with the silver(I) ion through the amino nitrogen atom. Salicylic acid molecules play an important role in the construction of the three-dimensional network structure through weak interactions. In addition, thermogravimetric analysis, stability, and silver(I) ion release experiments indicate that these complexes have good stability and slow ion release rates. Cell toxicity and antibacterial tests were conducted on selected cell lines and microorganisms using complexes 1-3, and compared with silver(I) salts, organic ligands, and antibiotic. All complexes exhibit better biocompatibility and certain anti-tumor selectivity than silver(I) salts. From the perspective of microbial toxicity, complexes 1-3 all have significant inhibitory effects on three bacteria strains, with complex 1 having the strongest antibacterial activity, exhibiting 4-6 times higher activity against certain strains than AgNO₃ and chloramphenicol. Mechanism studies have shown that cell wall perforation and imbalance of intracellular ROS levels may be possible reasons for silver(I) complexes induced bacterial cell death. The biofilm removal experiment further proves the potential use of silver(I) complexes 1-3 in the treatment of bacterial infections.

2025-04-15·Chinese Journal of Chemistry

Aggregation‐Dependent Polymer Photochromism via Double Intramolecular Hydrogen Bonds from Excited State Intramolecular Proton Transfer

作者: Hu, Shui ; Hu, Huan ; Zhou, Jingyuan ; Ma, Zhiyong ; Cheng, Xin ; Ma, Zhimin ; Li, Yongjie ; Chen, Mingzhi

Comprehensive SummaryExcited‐state intramolecular proton transfer (ESIPT) involves photochemical tautomerization between two excited states (E* and K*) via intramolecular proton transfer. Developing polymer photochromism based on the photochemical tautomerization of organic ESIPT molecules has been rarely reported. We report the ESIPT molecule HBT‐2OH exhibits concentration‐dependent photochromic behavior in a polyurethane (PU) network. At low concentrations, HBT‐2OH primarily exists in the trans‐enol configuration without intramolecular OH···N hydrogen bonds in PU, emitting blue fluorescence at ~464 nm (enol emission). Upon UV irradiation, the dihedral angle between the proton donor and acceptor twists to form an intramolecular OH···N H‐bond, converting trans‐enol to cis‐enol and resulting in ESIPT with pale yellow fluorescence at ~603 nm (keto emission). The photochromic effect of HBT‐2OH@PU diminishes at high concentrations due to that aggregation favors the cis‐enol form. Control molecules HBT, HBO‐2OH, and HBI‐2OH show no photochromism in PU, confirming that ethanolyl branches and intramolecular OH···S hydrogen bonds stabilize the trans‐enol configuration of HBT‐2OH. Incorporating these molecules into PMMA and PCL networks demonstrates that increased free volume and smaller aggregates enhance photochromism by reducing resistance to dihedral angle twisting. Density functional theory (DFT) calculations further confirm stable intramolecular heteroatomic hydrogen bonds (OH···S) exist in HBT‐2OH. This study offers new theoretical insights and opens avenues for research on polymer based photochromic materials.

2025-03-05·Journal of the American Society for Mass Spectrometry

What Drives the Vehicle Mechanism? Protonation Isomer Interconversion of Arylamine Derivatives Probed with Solvent-Mediated Kinetics

Article

作者: Shiels, Oisin J. ; Maccarone, Alan T. ; Ucur, Boris ; Blanksby, Stephen J. ; Trevitt, Adam J.

Reactions with mobile protons occur under electrospray ionization (ESI) in many applications of mass spectrometry. Understanding how protonation isomers (protomers) form and how molecular structure influences protomer interconversion provides fundamental insight into ESI mechanisms, which can then be exploited to rationalize ion mobility and ion activation processes for robust analyte detection. Using ten arylamine protomer systems, this paper establishes the key substrate properties that influence protomer isomerism. Protomers from ten arylamines are separated by differential ion mobility spectrometry (DMS) mass spectrometry and identified by characteristic collision-induced dissociation mass spectra. These assignments are further rationalized using quantum chemical calculations (M06-2X/6-31G(2df,p)). Based on these assignments, mobility-selected protomers are then allowed to react with methanol vapor under atmospheric and reduced pressure conditions (2.5 mTorr, 300 K). The latter enabled measurements of the second-order rate coefficients for methanol-catalyzed protomer isomerization, which span 3.9 × 10^-11-2 × 10^-13 cm³ molecule^-1 s^-1. Double-hybrid quantum chemical calculations (DSD-PBEP86-D3(BJ)/aug-cc-pVDZ) show that the direction of proton transfer is controlled by protomer relative stability, whereas reaction rates are controlled by a key transition state that separates the protonation sites. Computational exploration of a larger substituted-arylamine test-set shows that the protomer proton affinity generally correlates with energy of the key transition state. Applying the Bell-Evans-Polanyi principle to this reaction set highlights that outliers in the predictive model correspond to transition states with significant displacements along the reaction coordinate. This archetype system of derivatized arylamines provides a foundation to understand how substrate functionalization influences protomer isomerism for ions during ESI and predicts protonation isomer distributions.

100 项与对氨水杨酸钙相关的药物交易

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