ChemistryOpen最新文献

Gold-coated silver nanoparticles (Ag@AuNPs) are synthesized by green synthesis using Vaccinium corymbosum as reducing agent. The obtained Ag@AuNPs present a core-shell structure with nanostar shape. The absorption spectrum of these nanoparticles shows a prominent band centred at 680 nm, within the optimal range for photothermal applications. Dispersions of Ag@AuNPs in water, 1.87 10¹⁰ NPs/mL, reach a temperature of 44.3 °C under laser excitation in 10 minutes, which is suitable for hyperthermia therapy. The internalization of Ag@AuNPs, at a concentration of 3 10⁸ NPs/ml, by macrophages (Raw 264.7), human fibroblasts (Hs27), and cancer cells (4T1) is confirmed by transmission electron microscopy. Cytotoxicity studies demonstrate that at this concentration the cells are viable.

Conversion of CO₂ to high value products was considered as a focused issue towards carbon neutrality. Photocatalysis held the potential to realize the target, and graphitic carbon nitride (g-C₃N₄) was a competitive candidate. The photocatalytic efficiency of g-C₃N₄ limited by the weak adsorption of CO₂ and easy recombination of charge carriers. Herein, Na ion and cyano defects was induced into g-C₃N₄ simultaneously using NaHSO₃ as alkali molten salt to work out these obstacles. The optimized photocatalyst 3 Na-CN (the weight of NaHSO₃ was 1.5 g) exhibited the highest CO yield (21.5 μmol g^-1 h^-1), which was 5 times than that of pristine g-C₃N₄ (4.29 μmol g^-1 h^-1). By means of experiments and characterization, 3 Na-CN displayed better performance in both light utilization and charge separation, which was reflected by the improved photocurrent response, decreased electrochemical impedance, markedly diminished fluorescence intensity, and shortened fluorescence lifetime. This result could be ascribed to the facilitation of electron-hole separation induced by cyano defects, as well as the enhancement in CO₂ adsorption and activation mediated by the Na ion. This work offers a new perspective on dual modulation of graphitic carbon nitride and paves the way for the design of CO₂ reduction photocatalyst.

The environmentally friendly conversion of methane to value-added chemicals is studied by ab-initio calculations. We focus on the adsorption and dehydrogenation of methane were investigated on Ir13 cluster supported by boron nitrogen co-doped graphene (BNG). We show that the BNG-Ir₁₃ cluster with low oxygen coverage exhibits more negative adsorption energy of methane (-0.44 eV) and lower activation energy barrier for its dissociation (1.24 eV for the second dehydrogenation step) compared to the cluster with high oxygen coverage. Next, assuming abundant CH₃ and CH₂ species due to a proper temperature control preventing further dehydrogenation, we study competitive C-O coupling reactions leading to the formation of value-added chemicals. The activation energy barriers for the formation of methanol and formaldehyde are on BNG-Ir₁₃ are once again lower at a lower oxygen coverage. Furthermore, we study hydrogen recombination and confirm that H₂ molecules can be formed on these surfaces. Based on these findings, the low-oxygen-coverage BNG-Ir₁₃ cluster emerges as a promising catalyst for the selective conversion of methane to methanol and formaldehyde, as well as for hydrogen production.

The thermal unfolding of lysozyme in aqueous solution has been analyzed by (nano) differential scanning fluorimetry (nanoDSF) and differential scanning calorimetry (DSC). In addition, dynamic light scattering (DLS) acquired in parallel to the DSF measurements, was used to confirm that the change in hydrodynamic radius upon unfolding is rather small (R_H,f =1.75 nm in the folded state; and R_H,u=1.91 nm in the unfolded state). NanoDSF measurements were evaluated to characterize the folding/unfolding transition within the classical two-state folding model. The temperature of unfolding (T_m) is found to be the most robust quantity. The unfolding enthalpy $\Delta H_u$ and the change of specific heat were also obtained and errors in the range of 5-10 % and 30-50 % were determined, respectively. A comparison of thermodynamic parameters from nanoDSF and DSC measurements provides evidence for an increasing unfolding enthalpy $\Delta H_u$ with protein concentration. A comparison with data from literature suggests that a weak association in the folded state can lead to the observed change of the unfolding enthalpy. For Δc_p significantly higher values is deduced from the analysis of temperature dependent nanoDSF measurements (10 kJ/(K mol)) as compare to DSC (3-5 kJ/(K mol)).

The rational synthesis of three β-meso-fused porphyrins with a step-wise increasing π-system size is presented. The synthetic route, which introduces a five-membered ring between the macrocycle and an aromatic fragment, is modular in its nature and proceeds straightforwardly. The well-soluble conjugates have intriguing optical properties, namely bathochromically shifted and flattened absorption curves. Density functional theory (DFT) calculations provide insights into the electronic structure and transitions, unveiling small HOMO-LUMO gaps.

A new class of non-ionic dendritic amphiphiles has been developed from biobased chemicals, in particular glycerol-based dendrons coupled to commercially available acids via the Steglich esterification process. These non-ionic amphiphiles are functionalized with different hydrophobic segments to investigate the contribution of the same towards their guest transport behaviour. Therefore, different alkyl chains i.e, C8 and C12, as well as two different aromatic units were introduced as a hydrophobic segments and G1-oligo-glycerol as a hydrophilic segment. Their physicochemical properties were characterized by different techniques such as dynamic light scattering and fluorescence measurements. The results show that these amphiphiles form a very uniform micellar supramolecular structures that is independent of the hydrophobic system. The critical micelle concentration for the prepared non-ionic amphiphiles was found to be in the range of 0.3 to 1.8 mg/mL, which depend on the type of hydrophobic units. The encapsulation capacities of the amphiphiles were tested using Nile Red and Nimodipine as model dye and drug, respectively. The encapsulation studies showed a preference for C12- and pyrene-based amphiphiles through relatively different mechanisms unraveled by molecular dynamics (MD) simulations. Further, the cytotoxicity and cellular uptake of these systems as well as the release profiles were investigated.

The synthesis of 4,5-bis(hydroxymethyl)-2-methylpyridin-3-ol tetraphenylborate complex in water using an anion exchange process yielded more than 76 %. The resulting white complex was obtained and characterized using various spectroscopic and analytical techniques, including ultraviolet, infrared radiation (IR), mass, elemental analysis, and nuclear magnetic resonance (NMR). The antimicrobial activity of the formed ion-associate complex was evaluated. The structural, electrical, and bonding properties of a novel pyridoxine-tetraphenylborate ion-pair complex was explored using B3LYP/6-311G(d,p) DFT simulations. Geometries designed for negative complexation energy showed thermodynamically beneficial complex formation. Reduced density gradient (RDG) analysis and non-covalent interaction (NCI) plots showed that van der Waals forces are essential to complex stability. Quantum Theory of Atoms in Molecules (QTAIM) study detected weak and moderate hydrogen bonds in the complex using bond critical point (BCP) features. These results reveal how molecules form and stabilize the pyridoxine-tetraphenylborate ion-pair complex. To know the interaction between receptors and bioactive chemicals, one must understand the mechanism of the ionic complexes formed between bioactive chemicals and/or organic molecules.

The front cover depicts a α-Fe₂O₃/CuO/CuFe₂O₄ ternary nanocomposite, a combination of rhombohedral hematite, monoclinic CuO, and tetragonal CuFe₂O₄. This novel composite is synthesized using a one-step sol-gel auto combustion technique, which is effective as an antifungal agent, antioxidant, and drug nanocarrier. More details can be found in the Research Article by Sagar Kumar Dutta and co-workers (DOI: 10.1002/open.202400277).

In the search for new anticancer compounds, quinoline and piperazine moieties represent the most promising pharmacophoric fragments for the development of more effective drugs. A particularly interesting approach in medicinal chemistry is molecular hybridization, where different known components are integrated into a single chemical entity, resulting in hybrid molecules with enhanced biological activity. In this study, we have developed a new series of 4-(4-benzoylpiperazin-1-yl)-6-nitroquinoline-3-carbonitrile compounds (8 a-l), with potential anticancer effect, by combining the quinoline, the piperazinyl and the benzoylamino moieties. The rationalized compounds (8 a-l) were first evaluated in silico to assess the ADMET and drug-likeness profiles, synthesized using appropriate synthetic strategies and then tested in vitro under the National Cancer Institute DTP-NCI60 program. The entire series exhibited potent anticancer activity against the renal cell carcinoma (RCC) cell line UO-31, with compounds 8 c and 8 g effectively inhibiting cancer cell growth without excessive cytotoxic effects (growth percentages of -7 and -19, respectively). In silico induced fit docking (IFD) and molecular dynamics (MD) studies provided further insights into the putative mechanisms of action for both compounds, which were predicted to strongly bind key oncogenic proteins involved in RCC progression. The promising in vitro and in silico results herein presented provide a solid foundation for the development of a new series of small heterocyclic molecules with anticancer activity.

A series of C,O-chelated organotin(IV) alkoxides, L₂PhSnO^tBu (4), L₂PhSnOMe (6), L₂Sn(O^tBu)₂ (11), and siloxides L₂PhSnOSiPh₃ (3), L₂Sn(OSiPh₃)₂ (10) (L=[2-(CH₂O)₂CH]C₆H₄), was prepared by salt elimination reactions. They were obtained from the organotin(IV) iodides L₂PhSnI (1) or L₂SnI₂ (2) upon reactions with ^tBuOK, MeONa or Ph₃SiONa, respectively, in dry THF or methanol. Under non-inert conditions, compounds 4 and 6 undergo combined hydrolysis and condensation to give the hexaorganodistannoxane (L₂PhSn)₂O (5). The stannoxane 5 is easily hydrolysed to L₂PhSnOH (7), which quickly converts back when heated. Basic hydrolysis of diiodide 2 produces the cyclic oxide (L₂SnO)₃ (8). Its reaction with an equimolar amount of Ph₃SiONa gives only a mixture of the expected L₂SnI(OSiPh₃) (9), 10 and the precursor, 2. Yet, 8 shows a unique reactivity pattern when combine with m-tolyl boronic acid, affording stannaboroxane (L₂SnO)₂OB(m-tol) (12). All the isolated species were characterised in solution by NMR spectroscopy and mass spectrometry. The solid-state molecular structures of 1-5, 10-12 were established by single-crystal X-ray diffraction (XRD). Additionally, thermogravimetric analysis of 3-5, 8, 10, and 12 was conducted.