Zinc thiolate bonds are intriguing targets of study because of their redox noninnocence and prevalence in bioinorganic sites. A five-coordinate zinc dithiolate complex [EtN][LZn] (HL = ,'-di(2-sulfhydrylphenyl)-pyridine-2,6-dicarboxamide) was synthesized to study the oxidative reactivity of zinc thiolate bonds. Multiple chemically reversible reactions of the zinc thiolate bonds were identified. Oxidation of [EtN][LZn] with iodine resulted in structural rearrangement to a bimetallic disulfide-bridged complex. In contrast, the addition of elemental sulfur to [EtN][LZn] resulted in the insertion of a neutral S fragment into the Zn-thiolate bond to selectively form an unusual monometallic tetrasulfanido complex. When oxidized, this tetrasulfanido compound rearranged to form a bimetallic trisulfide-bridged complex. The observed diversity of zinc thiolate reactivity, particularly with sulfur, is likely important in biological contexts.
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http://dx.doi.org/10.1021/acs.inorgchem.9b01074 | DOI Listing |
Metallomics
October 2024
Department of Chemistry, 6128 Burke Laboratory, Dartmouth College, Hanover, NH 03755, USA.
The small Cys-rich protein metallothionein (MT) binds several metal ions in clusters within two domains. While the affinity of MT for both toxic and essential metals has been well studied, the thermodynamics of this binding has not. We have used isothermal titration calorimetry measurements to quantify the change in enthalpy (ΔH) and change in entropy (ΔS) when metal ions bind to the two ubiquitous isoforms of MT.
View Article and Find Full Text PDFJ Org Chem
September 2024
Technical Institute of Fluorochemistry (TIF), School of Chemistry and Molecular Engineering, School of Flexible Electronics (Future Technologies), Nanjing Tech University, Nanjing 211816, China.
A zinc-mediated cross-electrophile coupling of benzyl sulfonium salts with thiosulfonates via C-S bond cleavage was achieved. The reductive thiolation proceeded well under transition metal-free conditions to afford the desired benzyl sulfides in good yields, exhibiting both broad substrate scope and good functionality tolerance. In addition, the reaction could be applied to the use of selenosulfonate as an effective selenylation agent and be subjected to scale-up synthesis.
View Article and Find Full Text PDFInorg Chem
August 2024
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India.
A comparative bioinspired reactivity study of new binuclear Zn(II) complexes featuring coordinated thiolate, selenolate, trisulfide and diselenide in relation with (i) the generation of reactive sulfur/selenium species (RSS/RSeS), (ii) the oxygen dependent oxidation and disproportionation of polysulfide (S) to produce sulfite (SO), thiosulfate (SO) and sulfide (S) by sulfur oxygenase reductase (SOR), and (iii) the reaction of S with nitrite (NO) to generate thionitrite (SNO), perthionitrite (SSNO) and nitric oxide (NO), is presented. The binuclear Zn(II)-thiolate/selenolate complexes could react with elemental sulfur to generate RSS/RSeS while similar reactions involving elemental selenium could not generate RSeS. The dizinc(II)-S and the dizinc(II)-Se complexes could react with dioxygen (O) to generate binuclear Zn(II) complexes featuring coordinated thiosulfate (SO) and selenite (SeO), respectively.
View Article and Find Full Text PDFChempluschem
September 2024
Dipartimento di Scienze Chimiche Università degli Studi di Padova, Via Marzolo 1, 35131, Padova, Italy.
The reactivity of Zn tetrahedral complexes with HO was investigated in silico, as a first step in their disruption process. The substrates were chosen to represent the cores of three different zinc finger protein motifs, i. e.
View Article and Find Full Text PDFChemistry
July 2024
Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
4- and 5-coordinate zinc thiolate complexes supported either by bis(carboxamide)pyridine frameworks or by substituted tris(pyrazolyl)borate ligands react with elemental sulfur (S) following two distinct pathways. Some zinc thiolate moieties insert sulfur atoms to form zinc polysulfanide complexes, while others reduce sulfur and oxidize the thiolate. Here, we compare the effects of ligand electronics, strain, and sterics for selecting the respective reaction pathway.
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