Cu 2+ -selective turn-on fluorescence signaling based on metal-induced hydrolysis of pyrenecarbohydrazide

Substituent effects on spin-crossover Fe(II)N4O2 pyrenylhydrazone complexes

Multifunctional magnetic materials have broad application prospects in molecular switches and information storage. In this study, four mononuclear Fe(II) complexes are synthesized using a series of pyrenylhydrazone ligands HL1-4. Two deprotonated ligands are coordinated to the iron(II) ions in an enolic form, leading to neutral complexes FeII(Lx)2·xsol with a FeIIN4O2 octahedral coordination environment. Magnetic measurements suggest that complex Fe(L1)2·2ACE (1·2ACE, ACE = acetone) is mainly low spin below 300 K and complex Fe(L3)2·ACE (3·ACE) is high spin, whereas complexes Fe(L2)2 (2) and Fe(L4)2·6H2O (4·6H2O) exhibit gradual spin crossover behavior. The spin states of complexes 1-4 are confirmed by single-crystal X-ray diffraction analysis. The substituent effect on the magnetic properties of the complexes is significant in this system. Temperature-dependent fluorescence emission spectra show the coexistence but no coupling effect of spin crossover and fluorescence for complexes 2 and 4·6H2O.

Removal of Formaldehyde and Its Analogues Using a Hybrid Assembly of Pyrene-Modified Hydrazide and rGO: A Negative Carbon Emission and Green Chemical Decomposition Method

Indoor gaseous formaldehyde is the main environmental pollutant that can cause fatal threats to human health. A number of physical and chemical methods have been developed to tackle this issue. However, the existing methods are still unsatisfactory to meet the requirement of sustainable development owing to the flaws of low efficiency and reversible or second pollution. Herein, a chemical method based on a nucleophilic reaction between hydrazine and aldehyde that generates the only by-product of H₂O is designed for the removal of formaldehyde. 1-Pyrenebutyric hydrazide was synthesized by a simple esterification reaction and then self-assembled on reduced graphene oxide (rGO) with a large surface area by forming π-π stacking to obtain a composite for chemical removal of gaseous formaldehyde under ambient conditions. In a practical test, the formaldehyde removal rate could reach 91% of the theoretical value, which meets the requirement for commercial formaldehyde removal applications. After 10 times recycling, the formaldehyde removal rate still remains as high as 85%. Moreover, the composite could be regenerated in weak acidic media, which greatly reduce the manufacturing cost in practical applications.

A Cu2+-selective colorimetric-fluorometric sensor based on an anthracenyl-modified oxacalix[4]arene

An anthracenyl-modified oxacalix[4]arene with imine linkages exhibits highly selective and sensitive detection of Cu2+via drastic colour change and enhanced FL.

Development of Fungal Selective Amphiphilic Kanamycin: Cost-Effective Synthesis and Use of Fluorescent Analogs for Mode of Action Investigation

Amphiphilic aminoglycosides have attracted interest due to their novel antifungal activities. A crucial but often neglected factor for drug development in academia is cost of production. Herein is reported a one-step, inexpensive synthesis of amphiphilic alkyl kanamycins constituted with only natural components. The synthetic methodology also enabled the preparation of a series fluorescent amphiphilic aryl kanamycins for direct structure-activity mode of action studies. The lead compounds showed prominent antifungal activities against a panel of fungi, including Fusarium graminearum, Cryptococcus neoformans, and several Candida sp., and also significant antibacterial activities. With fluorescence-based whole cell assays, the aryl amphiphilic kanamycins were observed to permeabilize fungal surface membranes at faster rates than bacterial surface membranes. Also, the antifungal action of the amphiphilic kanamycins was observed to occur in a biphasic mode with an initial fast phase correlated with rapid membrane permeabilization at subminimal inhibitory concentrations and a slower phase membrane permeabilization that elevates the reactive oxygen species production leading to cell death. Inactive hydrophobic amphiphilic kanamycins displayed no membrane permeabilization. The results offer cost-effective methods for producing amphiphilic kanamycins and reveal insights into how nonfungal specific amphiphilic kanamycins can be employed for fungal specific diagnostic and therapeutic applications.