Brønsted Acidic Dicationic Ionic Liquid Immobilized on Fe 3 O 4 @SiO 2 Nanoparticles as an Efficient and Magnetically Separable Catalyst for the Synthesis of Bispyrazoles

Impact of Choline Hydroxide-Supported Magnetic Nanoparticles on Peroxidase Activity and Conformational Stability of Cytochrome c

Nanotechnology has advanced significantly; however, little is known about the potential implications on human health-related issues, particularly blood carrying enzymes. Ionic liquids are also well-recognized for maintaining the structure and activity of enzymes. In this regard, we delineate a facile synthetic approach of preparation of Fe3O4 nanoparticles (NPs) as well as choline hydroxide [CH][OH] ionic liquid (IL)-supported Fe3O4 NPs (Fe3O4-CHOH). This approach of combining magnetic nanoparticles (MNPs) with IL results in distinctive properties, which may offer enormous utility in the field of biomedical research due to the effortless separation of MNPs by an external magnetic field. Detailed characterization of MNPs including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) was carried out. The biomolecular interactions of Fe3O4 and Fe3O4-CHOH NPs with cytochrome c (Cyt c) were studied in detail using various spectroscopic and microscopic techniques. From spectroscopic studies, it can be concluded that the secondary structure of Cyt c is more stable in the presence of Fe3O4-CHOH NPs than Fe3O4 NPs. The binding constant of Cyt c in the presence of MNPs was also calculated using the Benesi-Hildebrand equation. Furthermore, dynamic light scattering (DLS), ζ-potential, and microscopic studies were performed to study the interaction of Cyt c with MNPs. These studies provided evidence favoring the formation of bionanoconjugates of Cyt c with MNPs. Moreover, the enzymatic activity of Cyt c increases in the presence of both MNPs. The peroxidase activity of Cyt c in MNPs explicitly elucidates that the enzyme is preserved for a long time in the presence of Fe3O4-CHOH NPs. Later on, TEM and field emission scanning electron microscopy (FESEM) were also performed to gather more information regarding the morphology of Cyt c in the presence of MNPs.

Ionic liquids revolutionizing biomedicine: recent advances and emerging opportunities

Ionic liquids (ILs), due to their inherent structural tunability, outstanding miscibility behavior, and excellent electrochemical properties, have attracted significant research attention in the biomedical field. As the application of ILs in biomedicine is a rapidly emerging field, there is still a need for systematic analyses and summaries to further advance their development. This review presents a comprehensive survey on the utilization of ILs in the biomedical field. It specifically emphasizes the diverse structures and properties of ILs with their relevance in various biomedical applications. Subsequently, we summarize the mechanisms of ILs as potential drug candidates, exploring their effects on various organisms ranging from cell membranes to organelles, proteins, and nucleic acids. Furthermore, the application of ILs as extractants and catalysts in pharmaceutical engineering is introduced. In addition, we thoroughly review and analyze the applications of ILs in disease diagnosis and delivery systems. By offering an extensive analysis of recent research, our objective is to inspire new ideas and pathways for the design of innovative biomedical technologies based on ILs.

Recent Advances in Imidazolium-Based Dicationic Ionic Liquids as Organocatalysts: A Mini-Review

Imidazolium-based dicationic ionic liquids (DILs) are gaining considerable space in the field of organocatalysis mainly due to the opportunities in offering new possible applicable structural variations. In addition to the well-known variables which made the ionic liquids (ILs) famous as the type of cation and anion used, the nature of the molecular spacer moiety turns out a further possibility to improve some physicochemical properties, for example, solubility, acidity, electrochemical behavior, and so on. For this reason, this class of ionic liquids has been considered as possible competitors to their corresponding monocationic salts in replacing common catalysts in organic synthesis, particularly in cases in which their bidentate nature could positively affect the catalytic activity. This mini-review is intended to highlight the progress carried out in the last six years in the field of organocatalysis, including DILs as such and as hybrids with polymers, nanomaterials, and composites.

Synthesis of 4,4'-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) and evaluation of their antioxidant and anticancer activities

Background

Pyrazoles have attracted particular attention due to the diverse biological activities associated with this heterocyclic system, and some have been shown to be cytotoxic to several human cell lines. Several drugs currently on the market have this heterocycle as the key structural motif, and some have been approved for the treatment of different types of cancer.

Results

4,4ʹ-(Arylmethylene)bis(1H-pyrazol-5-ols) derivatives 3a–q were synthetized by a three components reaction of 3-methyl-1-phenyl-5-pyrazolone (1) with various benzaldehydes 2 catalyzed by sodium acetate at room temperature. The structures of all synthesized compounds were characterized by physicochemical properties and spectral means (IR and NMR) and were evaluated for their radical scavenging activity by DPPH assay and tested in vitro on colorectal RKO carcinoma cells in order to determine their cytotoxic properties. All 4,4ʹ-(arylmethylene)bis(1H-pyrazol-5-ols) derivatives 3a–q were synthetized in high to excellent yield, and pure products were isolated by simple filtration. All compounds have good radical scavenging activity, and half of them are more active than ascorbic acid used as standard.

Conclusion

Several derivatives proved to be cytotoxic in the RKO cell line. In particular, compound 3i proved to be a very potent scavenger with an IC₅₀ of 6.2 ± 0.6 µM and exhibited an IC₅₀ of 9.9 ± 1.1 μM against RKO cell. Autophagy proteins were activated as a survival mechanism, whereas the predominant pathway of death was p53-mediated apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-021-00765-y.

Recovery/Reuse of Heterogeneous Supported Spent Catalysts

The rapid separation and efficient recycling of catalysts after a catalytic reaction are considered important requirements along with the high catalytic performances. In this view, although heterogeneous catalysis is generally less efficient if compared to the homogeneous type, it is generally preferred since it benefits from the easy recovery of the catalyst. Recycling of heterogeneous catalysts using traditional methods of separation such as extraction, filtration, vacuum distillation, or centrifugation is tedious and time-consuming. They are uneconomic processes and, hence, they cannot be carried out in the industrial scale. For these limitations, today, the research is devoted to the development of new methods that allow a good separation and recycling of catalysts. The separation process should follow a procedure economically and technically feasible with a minimal loss of the solid catalyst. The aim of this work is to provide an overview about the current trends in the methods of separation/recycling used in the heterogeneous catalysis.

Imidazolium-based ionic liquid immobilized on functionalized magnetic hydrotalcite (Fe3O4/HT-IM): as an efficient heterogeneous magnetic nanocatalyst for chemical fixation of carbon dioxide under green conditions

Fe₃O₄/HT-IM with plate-like morphology was synthesized as a novel and highly effective magnetic nanocatalyst and applied in chemical fixation.