Silybin, a natural occurring flavolignan isolated from the fruits of Silibum marianum, has been reported to exert antioxidant and free radical scavenging abilities. It was suggested to act also as an iron chelator. The complexation and protonation equilibria of the ferric complex of this compound have been studied by potentiometric, spectrophotometric and electrochemical techniques. The formation of the complex silybin-Ga(III) in anhydrous DMSO-d6 has been studied by 1H NMR spectroscopy. Mass spectrometry and infrared spectroscopy on silybin-Fe(III) complex confirm all data obtained by 1H NMR spectroscopy. The experimental results show that silybin binds Fe(III) even at acidic pH. Different ternary complexes were observed at increasing methoxide ion concentration and their stability constants have been calculated. The results show the possible role of silybin in relation to the chelation therapy of chronic iron overload, as occurs in the treatment of Cooley's anemia.
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http://dx.doi.org/10.1016/s0162-0134(01)00198-2 | DOI Listing |
RSC Adv
January 2025
Department of Chemistry, Faculty of Science (Boys), Al-Azhar University 11884 Nasr City Cairo Egypt
Herein, novel thiazolo[4,5-]quinoxalin-2-ones 2-6 and thiazolo[4,5-]quinoxalin-2(3)-imines 7-9 were synthesized and characterized using elemental analysis, IR spectroscopy, and H/C NMR to confirm their structures. The efficacy of the newly designed thiazolo-quinoxalines 2, 3, 4, 5, 7, 8, and 9 against the cotton leafworm (2nd and 4th instar larvae) was evaluated, and results revealed insecticidal activity with variable and good mortality percentages. A SAR study was also discussed.
View Article and Find Full Text PDFACS Catal
October 2024
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.
A class of generated Lewis acid (LA) activated acridine complexes is reported, which act as potent photochemical catalysts for the oxidation of a variety of protected secondary amines. Acridine/LA complexes exhibit tunable excited state reduction potentials ranging from +2.07 to 2.
View Article and Find Full Text PDFOrganometallics
January 2025
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom.
Cyclopentadienyl anions ([Cp]) are pervasive ligands in coordination chemistry. In contrast, heavy-element derivatives of these ligands, particularly those that feature arsenic, are not as well developed. In this work, a new arsenic-based heterocycle with a structure analogous to [Cp] is presented.
View Article and Find Full Text PDFOrganometallics
January 2025
Organic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
We report the synthesis and characterization of a series of high- and low-spin dicobalt complexes of the PNNP expanded pincer ligand. Reacting this dinucleating ligand in its neutral form with two equiv of CoCl(tetrahydrofuran) yields a high-spin dicobalt complex featuring one Co inside and one Co outside of the dinucleating pocket. Performing the same reaction in the presence of two equivalents of KOtBu provides access to a high-spin dicobalt complex wherein both Co centers are bound within the PNNP pocket, and this complex also features a bridging OtBu ligand.
View Article and Find Full Text PDFSmall
January 2025
Institutes of Physical Science and Information Technology, Anhui Graphene Carbon Fiber Materials Research Center, Anhui University, Hefei, Anhui, 230601, P. R. China.
Photocatalytic hydrogen production is currently considered a clean and sustainable route to meet the energy and environmental issues. Among, heterojunction photocatalysts have been developed to improve their photocatalytic efficiency. Defect engineering of heterojunction photocatalysts is attractive due to it can perform as electron trap and change the band structure to optimize the interfacial separation rate of photogenerated electron-hole pairs.
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