Tuning of cross-Glaser products mediated by substrate-catalyst polymeric backbone interactions

Green carbon-carbon homocoupling of terminal alkynes by a silica supported Cu(II)-hydrazone coordination compound

A Cu(II) complex, [Cu(HL)(NO₃)(CH₃OH)]·CH₃OH (1), was obtained by the reaction of Cu(NO₃)₂·3H₂O and H2L in methanol solvent (H2L is (E)-4-amino-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide). H2L and compound 1 were characterized by various spectroscopic analyses and the molecular structure of [Cu(HL)(NO₃)(CH₃OH)]·CH₃OH was determined by single-crystal X-ray analysis. The results indicated the product is a mononuclear Cu(II) complex and contains a free NH₂ functional group on the structure of the ligand. [Cu(HL)(NO₃)(CH₃OH)]·CH₃OH was used for the preparation of a heterogeneous catalyst by supporting it on functionalized silica gel. The heterogeneous catalyst (Si-Cu) was prepared by an amidification reaction of [Cu(HL)(NO₃)(CH₃OH)]·CH₃OH with functionalized silica gel. The resulting silica-supported catalyst (Si-Cu) was characterized by TGA, FT-IR, EPR, DRS, EDS, XRD, SEM and XPS analyses. Si-Cu was employed in a carbon-carbon coupling reaction and the effects of the amount of Si-Cu and temperature were investigated in the catalytic coupling. The structure of one of the products of the catalytic reactions (C₁₆H₂₂O₂, CP1) was determined by single-crystal X-ray analysis, which proved the formation of a C-C bond and the production of di-acetylene by homocoupling of terminal alkyne. This catalytic system is stable and it can be reused for a coupling reaction without a significant change in its catalytic activity.

Cellulose-Conjugated Copper-Oxide Nanoparticles for the Treatment of Ethanol-Induced Gastric Ulcers in Wistar Rats

Gastric ulcer (GU) is the most common and chronic inflammatory condition mediated by multiple immune cells like neutrophils, macrophages, and lymphocytes with multiple pro-inflammatory cytokine interleukins such as IL-8, IL-10, IL-β, and interferon-γ (IFN-γ). Copper (Cu) is one of the essential micronutrients mainly found in the liver and brain. It plays a major role in metabolism, enzyme conversion, free radical scavenging, trafficking agents, and many others. Due to its various roles in the biological system, it can also be used as a therapeutic agent in many diseases like colon cancer, bone fracture healing, angiogenesis, as an antibacterial, wound-healing and radiotherapeutic agents. In this study, we used thiol-functionalized cellulose-conjugated copper-oxide nanoparticles (Cu^I/IIO NPs) synthesized under environmentally friendly conditions. We have evaluated the effects of cellulose-conjugated Cu^I/IIO NPs against ethanol-induced gastric ulcer in Wistar rats. The cellulose-conjugated Cu^I/IIO NPs were evaluated against different physical, histochemical, and inflammatory parameters. The NPs promoted mucosal healing by ameliorating ulcerative damage, restoring the histoarchitecture of gastric mucosa, and inhibiting pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), and other inflammatory biomarkers such as myeloperoxidase (MPO) activity and nitric oxide (NO) levels. The current study's findings suggest that cellulose-conjugated Cu^I/IIO NPs exerted antiulcer effects on the preclinical rat model and have promising potential as a novel therapeutic agent for the treatment of gastric ulcers.

Thiol-Functionalized Cellulose-Grafted Copper Oxide Nanoparticles for the Therapy of Experimental Colitis in Swiss Albino Mice

Ulcerative colitis (UC) is a chronic inflammatory disease, which deleteriously affects the lower end of the gastrointestinal tract, i.e., the colon and the rectum. UC affects colonic inflammatory homeostasis and disrupts intestinal barrier functions. Intestinal tissue damage activates the immune system and collectively worsens the disease condition via the production of various cytokines. Ongoing therapeutics of UC have marked limitations like rapid clearance, extensive first-pass metabolism, poor drug absorption, very low solubility, bioavailability, etc. Because of these restrictions, the management of UC demands a rational approach that selectively delivers the drug at the site of action to overcome the therapeutic limiting factors. Metallic nanoparticles (NPs) have good therapeutic efficacy against colitis, but their uses are limited due to adverse effects on the biological system. In this study, we have used biocompatible thiol-functionalized cellulose-grafted copper oxide nanoparticles (C-Cu^I/IIO NPs) to treat UC. The metal NPs alleviated the colitis condition as evidenced by the colon length and observed physical parameters. Analysis of histopathology demonstrated the recovery of the colon architecture damaged by dextran sulfate sodium-induced colitis. Treatment with C-Cu^I/IIO NPs reduced the disintegration of goblet cells and the retainment of sulfomucin. Significant downregulation of inflammatory markers like MPO activity, as well as levels of nitrite and TNF-α, was found following C-Cu^I/IIO NP treatment. The observations from the study suggested that intrarectal treatment of colitis with cellulose-based C-Cu^I/IIO NPs successfully combated the intestinal inflammatory condition.

Azolium Aurates as Pre-Catalysts for the Oxidative Coupling of Terminal Alkynes under Mild Conditions

A simple and efficient method for the oxidative coupling of terminal alkynes is reported for the first time, making use of imidazol(in)ium aurates as pre-catalysts. This approach displays high functional group tolerance and leads to a broad range of 1,3-diyne compounds in moderate to excellent yields using low catalyst loading and is performed in air under mild and sustainable conditions.

A systematic study to unravel the potential of using polysaccharides based organic-nanoparticles versus hybrid-nanoparticles for pesticide delivery

To daze conventional pesticide release limitations, nanotechnology-mediated pesticide delivery using natural polymers has been actively investigated. However, the lack of information on what are the beneficial/non-beneficial aspects of using hybrid- and organic-nanoparticles (NP) and among the polysaccharides which are better suited concerning pesticide loading efficiency (PLE wt%), entrapment efficiency, and sustained pesticide release (SPR %) has prompted us to investigate this study. In this report, we systematically investigated a series of polysaccharides such as starch (S), cellulose (C), aminocellulose (AC), and sodium carboxymethylcellulose (NaCMC) coated on magnetite NP (MNP, Fe₃O₄) and complete organic nanocarrier systems (starch and cellulose) that have no MNP part were compared for the PLE wt% and SPR % efficiencies for chlorpyrifos (ChP) insecticide. Overall, all nanocarriers (NCs) have shown good to excellent PLE wt% due to the smaller-sized NP obtained through optimal conditions. However, among the hybrid polysaccharides studied, starch MNP has shown a maximum PLE of 111 wt% in comparison with other polysaccharides (80-94 wt%) coated hybrid-NCs as well as with organic-NCs (81-87 wt%). The use of inorganic support does improve the PLE wt% markedly for starch but not for cellulose derivatives. Similarly, the SPR results of S-NP showed a remarkably better sustained release profile for ChP of 88% in 14 d. In contrast, other unfunctionalized and functionalized celluloses exhibited poor release profiles of 60%-20% for the same period. This study may help the researchers choose the right system for designing and achieving enhanced pesticide efficiency.