S-nitrosothiols (RSNOs) serve as ready sources of biological nitric oxide activity, especially in conjunction with copper centers. We report a novel pathway for the generation of NO within the coordination sphere of copper model complexes from reaction of copper(II) thiolates with S-nitrosothiols. Reaction of tris(pyrazolyl)borate copper(II) thiolates (iPr2)TpCu-SR (R = C6F5 or CPh3) with (t)BuSNO leads to formation of (iPr2)TpCu(NO) and the unsymmetrical disulfide RS-S(t)Bu. Quantum mechanical investigations with B3LYP-D3/6-311G(d) suggest formation of a κ(1)-N-RSNO adduct (iPr2)TpCu(SR)(R'SNO) that precedes release of RSSR' to deliver (iPr2)TpCu(NO). This process is reversible; reaction of (iPr2)TpCu(NO) (but not (iPr2)TpCu(NCMe)) with C6F5S-SC6F5 forms (iPr2)TpCu-SC6F5. Coupled with the facile, reversible reaction between (iPr2)TpCu(NO) and C6F5SNO to give (iPr2)TpCu-SC6F5 and 2 equiv NO, we outline a new, detailed catalytic cycle for NO generation from RSNOs at Cu.
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Angew Chem Int Ed Engl
January 2025
Institut de Chimie (UMR 7177), University of Strasbourg, CNRS, 4 Rue Blaise Pascal, 67081, Strasbourg, France.
Several copper-ligands, including 1,10-phenanthroline (Phen), have been investigated for anticancer purposes based on their capacity to bind excess copper (Cu) in cancer tissues and form redox active complexes able to catalyse the formation of reactive oxygen species (ROS), ultimately leading to oxidative stress and cell death. Glutathione (GSH) is a critical compound as it is highly concentrated intracellularly and can reduce and dissociate copper(II) from the ligand forming poorly redox-active copper(I)-thiolate clusters. Here we report that Cu-Phen speciation evolves in physiologically relevant GSH concentrations.
View Article and Find Full Text PDFACS Omega
June 2023
Department of Chemical Engineering, Birla Institute of Technology and Science-Pilani, K.K. Birla Goa Campus, Zuarinagar 403726, Goa, India.
A Cu(II) thiolato complex [CuL()] () (HL = -HOCHC(H)=NCHSH-) and the corresponding water-soluble stable sulfinato-O complex [CuL'()] () (HL' = -HOCHC(H)=NCHS(=O)OH) were synthesized and characterized using physicochemical techniques. Compound is found to be a dimer in the solid state as characterized using single-crystal X-ray crystallography. XPS studies clearly showed the differences in the sulfur oxidation states in and .
View Article and Find Full Text PDFJ Inorg Biochem
October 2021
Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia. Electronic address:
Bis(aminoacidato)copper(II) [Cu(aa)] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma. Since there are no experimental data in the literature about the geometries that physiological Cu(aa) could form with l-cysteine (Cys), that is, for bis(l-cysteinato)copper(II) [Cu(Cys)] and the ternary (l-histidinato)(l-cysteinato)copper(II) [Cu(His)(Cys)], this paper computationally examines the possible conformations that the two compounds could form with the Cys ligand having a protonated sulfur, as in the conventional zwitterion, which was determined to be prevailing in aqueous solution. These two amino acids can bind metals in a tridentate fashion and thus form many possible coordination patterns.
View Article and Find Full Text PDFData Brief
April 2021
Univ Paris Est Creteil, CNRS, ICMPE, UMR7182, F-94320 Thiais, France.
Fresh water resources on the earth are less than 0.2%; meanwhile, around 80% of the freshwater is consumed daily in agriculture, industries, and household activities [1], [2]. There is an essential need to develop efficient adsorbents for wastewater treatment [1], [2], [3], [4], [5], [6], in this regards, hereafter we present the rationale synthesis and characterization of hybrid natural bentonite clay modified with Calix [4] arene (denoted as B-S-Calix) as efficient adsorbents for toxic metals from wastewater.
View Article and Find Full Text PDFChemRxiv
July 2020
Beckman Institute, California Institute of Technology, Pasadena, CA 91125.
In an analysis of the structural stability of the coronavirus main protease (Mpro), we identified regions of the protein that could be disabled by cobalt(III)-cation binding to histidines and cysteines [1]. Here we have extended our work to include copper(II) chelates, which we have docked to HIS 41 and CYS 145 in the Mpro active-site region. We have found stable docked structures where Cu(II) could readily bond to the CYS 145 thiolate, which would be lethal to the enzyme.
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