Platinum and Palladium Complexes Bearing New (1R,2R)‐(–)‐1,2‐Diaminocyclohexane (DACH)‐Based Nitrogen Ligands: Evaluation of the Complexes Against L1210 Leukemia

The reaction of (1R,2R)‐(–)‐1,2‐diaminocyclohexane ( 1 ) [DACH] with the aldehyde (1R)‐(–)‐myrtenal ( 2 ) in MeOH afforded the bidentate diimine ligand, (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenylidene}‐1,2‐diaminocyclohexane ( 3 ) in a high yield. Reduction of 3 using LiAlH₄ led to the formation of the desired ligand ( 4 ) (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenyl}‐1,2‐diaminocyclohexane. Treatment of compound 4 with K₂PtCl₄ or K₂PdCl₄ yielded the corresponding platinum(II) and palladium(II) complexes, Pt‐5 and Pd‐6 , respectively. The reaction of compound 3 with K₂PtCl₄ gave the diimine complex Pt‐7 . The cytotoxic activity of the complexes Pt‐5 , Pd‐6 and Pt‐7 was tested and compared to the approved drugs, cisplatin ( Cis ‐Pt ) and oxaliplatin ( Ox‐Pt ). The complexes ( Pt‐5 , Pd‐6 and Pt‐7 ) inhibit L1210 cell line proliferation with an IC₅₀ of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.     

Ziziphus nummularia Attenuates the Malignant Phenotype of Human Pancreatic Cancer Cells: Role of ROS

Pancreatic cancer (PC) is the fourth leading cause of all cancer-related deaths. Despite major improvements in treating PC, low survival rate remains a major challenge, indicating the need for alternative approaches, including herbal medicine. Among medicinal plants is Ziziphus nummularia (family Rhamnaceae), which is a thorny shrub rich in bioactive molecules. Leaves of Ziziphus nummularia have been used to treat many pathological conditions, including cancer. However, their effects on human PC are still unknown. Here, we show that the treatment of human pancreatic ductal adenocarcinoma cells (Capan-2) with Ziziphus nummularia ethanolic extract (ZNE) (100–300 μg/mL) attenuated cell proliferation in a time- and concentration-dependent manner. Pretreatment with N-acetylcysteine, an ROS scavenger, attenuated the anti-proliferative effect of ZNE. In addition, ZNE significantly decreased the migratory and invasive capacity of Capan-2 with a concomitant downregulation of integrin α₂ and increased cell–cell aggregation. In addition, ZNE inhibited in ovo angiogenesis as well as reduced VEGF and nitric oxide levels. Furthermore, ZNE downregulated the ERK1/2 and NF-κB signaling pathways, which are known to drive tumorigenic and metastatic events. Taken together, our results suggest that ZNE can attenuate the malignant phenotype of Capan-2 by inhibiting hallmarks of PC. Our data also provide evidence for the potential anticancer effect of Ziziphus nummularia, which may represent a new resource of novel anticancer compounds, especially ones that can be utilized for the management of PC.     

Enhanced photodegradation of methylene blue with alkaline and transition‐metal ferrite nanophotocatalysts under direct sun light irradiation

It is highly desired to synthesize low‐cost photocatalysts for the degradation of colored dyes to safeguard our environment for the future generations. Here, we report an extremely efficient and low‐cost synthesis of alkaline earth and transition‐metal ferrite photocatalysts (MgFe₂O₄, CaFe₂O₄, BaFe₁₂O₁₉, CuFe₂O₄, and ZnFe₂O₄) from their chloride salts and their applications for the degradation of methylene blue (MB) dye under UV–visible and direct sunlight irradiation. The as‐prepared photocatalysts displayed enhanced photoactivities under both conditions of irradiation. After calcination at 600°C, the photocatalytic degradation increased significantly, and 96 and 85% MB was removed with ZnFe₂O₄ under UV–visible and direct sunlight irradiation, respectively. Moreover, large amounts of hydroxyl free radicals were produced under both irradiation conditions, which participated in the degradation of MB. The enhanced photodegradation activities of these photocatalysts are attributed to their extended visible light absorption and low bandgaps. This work will provide a feasible route to the synthesis of efficient and low‐cost photocatalysts to utilize sunlight for environmental remediation.     

Synthesis,spectral characterization and antibacterial activity of O,O’-dialkyl and alkylene dithiophosphatogold (III)dichloride; crystal structure of [S2POCMe2CMe2O]AuCl2

Abstract

O, O’-Dialkyl and alkylene dithiophosphatogold (III)dichloride complexes of the type [(RO)₂PS₂]AuCl₂ and [S₂POGO]AuCl₂, where R?=?Et, nPr, iPr, iBu, Ph, cyclohexyl and cyclopentyl, where G?=?CMe₂CMe₂-, have been synthesized in 80-90% yields by reaction of the corresponding acid or sodium salts of the appropriate dithiophosphoric acids in 1:1 ratio with gold (III) chloride in dry dichloromethane at room temperature. The compounds have been characterized by elemental analyses, IR and (¹H, ^l3C, and ³¹P) NMR. The crystal structure of [S₂POCMe₂CMe₂O]AuCl₂, was determined. These new complexes have shown their growth inhibiting potential against various bacterial strains with moderate to good activity.     

Adsorption kinetics and isotherm parameters of naphthalene onto natural- and chemically modified bentonite from aqueous solutions

Polycyclic aromatic hydrocarbons (PAHs) have widely been studied and a special concern because of their mutagenic and carcinogenic activities. In this study, natural- and chemically modified-bentonite were characterized by means of N₂ adsorption method, XRD, SEM, FT-IR, elemental and thermal analysis and zeta potential techniques and their adsorption behavior were then investigated toward naphthalene, which is the first member of the PAHs. The effects of various experimental parameters such as pH, contact time and temperature on adsorption were tested in the experiments. The optimum pH values for naphthalene adsorption onto natural bentonite (NB) and hexadecyltrimethylammonium bromide modified bentonite (HB) were found to be as 4.00 and 5.97, respectively. The equilibrium contact time was 60 min for both of the adsorbent. A comparison of the linear and nonlinear method of three widely used kinetic models, which are Lagergren-first order, the pseudo-second-order and Elovich kinetics, and the most popular isotherms, which are Langmuir and Freundlich, were examined to the experimental data of the adsorption of naphthalene onto NB and HB. The kinetic results indicated that the pseudo-second-order kinetic model with high correlation coefficients was more suitable than the other kinetic models e.g. Lagergren first-order and Elovich. All results showed that the modified bentonite can be used as an adsorbent to remove PAHs from aqueous solutions by using adsorption method due to its effectiveness, simplicity and low-cost than the other conventional methods.     

One-pot synthesis of oxygen-functionalized porous carbon from biowaste for rapid organics removal via peroxymonosulfate activation

Oxygen-functionalized porous carbon (PC-800) was fabricated through direct thermal treatment of biowaste under inert atmosphere. The PC-800 was systematically characterized and the results showed that the catalyst was extremely favorable for catalysis due to its high specific surface area (993 m²/g) and abundance active sites (ketonic groups). The results indicated that PC-800 can efficiently degrade acid orange 7 (AO7), and increasing the catalyst loading and PMS dosage have promotional effect on catalysis. The recyclability study showed that, while PC-800 can be reused for several cycles, the catalytic activity was partially deactivated due to the cannibalistic oxidation of PC-800 surface. Nevertheless, high mineralization extent (DOC removal = 70%) and ring opening of aromatic AO7 intermediates was achieved. It was also found that both radical and nonradical mechanisms were responsible for AO7 degradation. Overall, this study showed that biowaste can be facilely functionalized with oxygen functional groups for sustainable PMS activation.     

The removal of methylene blue as a remedy of dye-based marine pollution: a photocatalytic perspective

Research on Chemical Intermediates - The effluents containing the discarded water from the textile industry are graded as one of the foremost pollutants in all industrial sectors. The wide...     

Photochemically-Driven CO2 Release Using a Metastable-State Photoacid for Energy Efficient Direct Air Capture

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO₂ release, making the massive scale (GtCO₂/year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically-driven approach for CO₂ release by exploiting the unique properties of an indazole metastable-state photoacid (mPAH). Our measurements on simulated and amino acid-based DAC systems revealed the potential of mPAH to be used for CO₂ release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO₂ was found for the simulated and amino acid-based DAC systems, respectively. Our results confirm the feasibility of on-demand CO₂ release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents.     

Simultaneous lipidomic analysis of three families of bioactive lipid mediators leukotrienes, resolvins, protectins and related hydroxy-fatty acids by liquid chromatography/electrospray ionisation tandem mass spectrometry

Bioactive lipid mediators derived from polyunsaturated fatty acids (PUFA) exhibit a range of tissue- and cell-specific activities in many physiological and pathological processes. Electrospray ionisation tandem mass spectrometry coupled to liquid chromatography (LC/ESI-MS/MS) is a sensitive, versatile analytical methodology for the qualitative and quantitative analysis of lipid mediators. Here we present an LC/ESI-MS/MS assay for the simultaneous analysis of twenty mono- and poly-hydroxy-fatty acid derivatives of linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids. The assay was linear over the concentration range 1-100 pg/microL, whilst the limits of detection and quantitation were 10-20 and 20-50 pg, respectively. The recovery of the extraction methodology varied from 76-122% depending on the metabolite. This system is useful for profiling a range of biochemically related potent mediators including the newly discovered resolvins and protectins, and their precursor hydroxyeicosapentaenoic and hydroxydocosahexaenoic acids, and, consequently, advance our understanding of the role of PUFA in health and disease.     

Ion-sensitive "isothermal" responsive polymers prepared in water

Ion-sensitive responsive polymers are prepared under fully aqueous conditions using controlled radical polymerization. Variations in comonomer content and sequence lead to temperature and salt-dependent solution behavior, with cloud-points ranging by +/-40 degrees C following addition of Hofmeister series salts. A "hybrid" block copolymer, composed of a statistical sequence of monomers tipped with a hydrophilic block, formed stable micelle-like assemblies that exhibited burst release of an encapsulated model drug in response to addition of a kosmotrope, Na2SO4, at room temperature.