- A tetranitrosyl [4Fe-4S] cluster forms en route to roussins black anion: Nitric oxide reactivity of [Fe4S4(LS3)L] 2-
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Previous studies provide evidence that [4Fe-4S] clusters serve as targets of reactive nitrogen oxide species in biology. The products of this reaction range from dinitrosyliron complexes, [Fe(NO)2L2] -, to Roussins black anion, [Fe4S3(NO) 7]-. To date, the pathways by which these reactions occur have not been fully elucidated. In this study, we prepared the site-differentiated complexes [Fe4S4(LS 3)L]2- (LS3 = 1,3,5-tris(4,6-dimethyl-3- mercaptophenylthio)-2,4,6-tris(p-tolylthio)benzene; L = Cl, SEt, SPh, N 3, 2-SPyr, Tp, S2CNEt2) to serve as synthetic models for biological [4Fe-4S] clusters and studied their reactivity toward NO(g) and Ph3CSNO. The products were characterized by X-ray crystallography, mass spectrometry, and IR, electron paramagnetic resonance (EPR), and 1H NMR spectroscopy. In all cases reported here, the reactions proceed via formation of the S = 1/2 species [Fe4S4(NO)4]-, which ultimately converts to EPR-silent [Fe4S3(NO)7] -.
- Victor, Eric,Lippard, Stephen J.
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Read Online
- Photochemical metal-free aerobic oxidation of thiols to disulfides
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Thiol oxidation to disulfides is an area of great importance in organic synthesis, both for synthetic and biological purposes. Herein, we report a mild, inexpensive and green photochemical approach for the synthesis of both symmetrical and non-symmetrical disulfides, using metal-free and environmentally friendly conditions. Utilizing phenylglyoxylic acid as the photoinitiator, common household bulbs as the light source and a simple inorganic salt as the additive, a versatile oxidation of thiols leading to products in excellent yields is described. This journal is
- Spiliopoulou, Nikoleta,Kokotos, Christoforos G.
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supporting information
p. 546 - 551
(2021/01/28)
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- Glutathione peroxidase mimics based on conformationally-restricted,peri-like, 4,5-disubstituted fluorene dichalcogenides
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Glutathione peroxidase (GPx) regulates cellular peroxide levels through glutathione oxidation. GPx-mimics based on 4,5-disubstituted fluorene diselenides, their oxides, and ditellurides show catalytic activities consistent with conformational restriction
- Capperucci, Antonella,Figliola, Carlotta,Grainger, Richard S.,Jagdev, Kesar,Lownes, Jack W.,Male, Louise,Tanini, Damiano
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p. 10565 - 10569
(2021/12/27)
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- Iron(II/III) Halide Complexes Promote the Interconversion of Nitric Oxide and S-Nitrosothiols through Reversible Fe-S Interaction
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Heme and non-heme iron in biology mediate the storage/release of NO? from S-nitrosothiols as a means to control the biological concentration of NO?. Despite their importance in many physiological processes, the mechanisms of N-S bond formation/cleavage at Fe centers have been controversial. Herein, we report the interconversion of NO? and S-nitrosothiols mediated by FeII/FeIII chloride complexes. The reaction of 2 equiv of S-nitrosothiol (Ph3CSNO) with [Cl6FeII2]2- results in facile release of NO? and formation of iron(III) halothiolate. Detailed spectroscopic studies, including in situ UV-vis, IR, and M?ssbauer spectroscopy, support the interaction of the S atom with the FeII center. This is in contrast to the proposed mechanism of NO? release from the well-studied red product κ1-N bound S-nitrosothiol FeII complex, [(CN)5Fe(κ1-N-RSNO)]3-. Additionally, FeIII chloride can mediate NO? storage through the formation of S-nitrosothiols. Treatment of iron(III) halothiolate with 2 equiv of NO? regenerates Ph3CSNO with the FeII source trapped as the S = 3/2 {FeNO}7 species [Cl3FeNO]-, which is inert toward further coordination and activation of S-nitrosothiols. Our work demonstrates how labile iron can mediate the interconversion of NO?/thiolate and S-nitrosothiol, which has important implications toward how Nature manages the biological concentration of free NO?.
- Poptic, Anna L.,Zhang, Shiyu
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supporting information
p. 5190 - 5197
(2021/04/06)
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- Reactivity of [U(CH2SiMe2NSiMe3)(NR2)2] (R = SiMe3) with elemental chalcogens: Towards a better understanding of chalcogen atom transfer in the actinides
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The reaction of the U(iv) metallacycle, [U(CH2SiMe2NSiMe3)(NR2)2] (R = SiMe3) with the elemental chalcogens, E (E = S, Se, Te) affords the insertion products, [U(ECH2SiMe2/
- Smiles, Danil E.,Wu, Guang,Hayton, Trevor W.
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supporting information
p. 7563 - 7566
(2015/10/12)
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- Imidazole Promoted Highly Efficient Large-Scale Thiol-Free Synthesis of Symmetrical Disulfides in Aqueous Media
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A highly efficient and environmentally friendly method for the imidazole promoted preparation of symmetrical organic disulfides from Bunte salts is described. This thiol-free procedure produces the desired disulfides even on a large scale by reaction of Bunte salts with imidazole in good to high yields in aqueous media.
- Mokhtari, Babak,Kiasat, Ali Reza,Monjezi, Javid
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p. 1573 - 1579
(2015/09/15)
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- A copper(II) thiolate from reductive cleavage of an S-nitrosothiol
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S-Nitrosothiols RSNO represent circulating reservoirs of nitric oxide activity in the plasma and play intricate roles in protein function control in health and disease. While nitric oxide has been shown to reductively nitrosylate copper(II) centers to form copper(I) complexes and ENO species (E = R 2N, RO), well-characterized examples of the reverse reaction are rare. Employing the copper(I) β-diketiminate [Me2NN]Cu, we illustrate a clear example in which an RS-NO bond is cleaved to release NO gas with formation of a discrete copper(II) thiolate. The addition of Ph3CSNO to [Me2NN]Cu generates the three-coordinate copper(II) thiolate [Me2NN]CuSCPh3, which is unstable toward free NO.
- Melzer, Marie M.,Mossin, Susanne,Cardenas, Allan Jay P.,Williams, Kamille D.,Zhang, Shiyu,Meyer, Karsten,Warren, Timothy H.
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p. 8658 - 8660
(2012/11/07)
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- Aerobic oxidation of thiols to disulfides catalyzed by diaryl tellurides under photosensitized conditions
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Aerobic oxidation of thiols is efficiently catalyzed by diaryl tellurides such as bis(4-methoxyphenyl) telluride under photosensitized conditions to give the corresponding disulfides in good to excellent yields. In this catalytic system, the tellurone oligomer, produced by the reaction of a telluride with singlet oxygen, is assumed to be the active species and is capable of oxidizing 4 equiv of a thiol.
- Oba, Makoto,Tanaka, Kazuhito,Nishiyama, Kozaburo,Ando, Wataru
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experimental part
p. 4173 - 4177
(2011/06/26)
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- Easy and rapid method for disulfide syntheses using nanophase-manganese (VII) oxide coated clay
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Disulfide bond formation by the oxidation of several thiol compounds using nanophase manganese (VII) oxide coated clay (NM7O coated clay) in chlorinated, nonchlorinated (toluene), and polar solvents (water) is described. During the process, nitro and methoxy groups remain unaffected. The NM7O coated clay is easily prepared, stable, and inexpensive to manufacture. Furthermore, this and other studies prove that NM7O coated clay properties, i.e., mineralogy, chemical, and reactivity, are different from KMnO4. This rapid and facile synthesis coupled with the use of the recyclable NM7O coated clay catalyst will save energy due to low temperature and rapid reaction times, as well as minimal disposal problems, thus decreasing production costs.
- Gondi, Sudershan R.,Son, David Y.,Biehl, Edward R.,Vempati, Rajan K.
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scheme or table
p. 34 - 39
(2010/05/02)
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- Preparation of dithioselenides via a selenium transfer reagent
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The addition of two moles of thiol to a unique selenium-transfer reagent, bis azole selenide 4, results in very good isolated yields of dithioselenides (RS-Se-SR).
- Ryan, M. Dominic,Harpp, David N.
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p. 8829 - 8832
(2007/10/03)
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- Structure abd Chemistry of Chloro(triphenylmethyl)sulfanes
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The structures of chloro(triphenylmethyl)mono-, di-, and -trisulfanes were obtained.The monosulfane displayed a triclinic (P1) space group, a = 10.792(2) Angstroem, b = 15.090(2) Angstroem, c = 10.027(2) Angstroem, α = 100.15(1) deg, β = 103.13(1) deg, γ = 88.80(1) deg, Z = 4.The disulfane gave a triclinic (P1) space group, a = 9.758(1) Angstroem, b = 10.426(2) Angstroem, c = 9.1691(6) Angstroem, α = 97.52(1) deg, β = 90.116(1) deg, γ = 116.750(1) deg, Z = 2.The trisulfane gave an orthorhombic space group (Pna21), a = 9.224(1) Angstroem, b = 19.196(3) Angstroem, c = 10.308(1) Angstroem, Z = 4.The sulfenyl chlorides decompose above their melting points to mixtures consisting primarily of triphenylchloromethane and sulfur.The sulfur was determined to consist of several allotropes (S6, S7, S8 and S9).The di- and trisulfanes slowly decompose to the same products at room temperature; the decompositions are enhanced by light.The decomposition of the trisulfane in the presence of dienes gave adducts consistent with the transfer of a two-sulfur species.The disulfane and trisulfane undergo the normal nucleophilic substitution reactions of the monosulfanes.
- Williams, Charles R.,Britten, James F.,Harpp, David N.
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p. 806 - 812
(2007/10/02)
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- A simple method to prepare unsymmetrical di- tri- and tetrasulfides
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Unsymmetrical di- tri- and tetrasulfides can be prepared in a one-pot reaction using SO2Cl2 SCl2 and S2Cl2 respectively to permit coupling of the appropriate thiols.
- Derbesy, Gerard,Harpp, David N.
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p. 5381 - 5384
(2007/10/02)
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- ACTIVATION AND SYNTHETIC APPLICATIONS OF THIOSTANNANES. EFFICIENT CONVERSION OF THIOLS INTO DISULFIDES
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Various kinds of thiols are converted into the corresponding disulfides under mild conditions with the aid of alkoxystannane-ferric chloride.
- Sato, Tsuneo,Otera, Junzo,Nozaki, Hitosi
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p. 3591 - 3594
(2007/10/02)
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- Oxo and Thiovanadium(V) Thiolates
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Syntheses of oxovanadium(V) thiolates such as O = V(SR)3 (R = tC4H9, SiPh3) and O = V(OtC4H9)n(StC4H9)3-n (n = 1, 2) are described.The thiovanadium(V) compounds S = V(OtC4H9)3, S = V(StC4H9)(OtC4H9)2 and S = V(SSiPh3)3 have been prepared by various methods: substition using Lawesson reagent, oxidation of V(OtC4H9)4 by sulfur, or disproportionation reaction of VCl4 with LiSSiPh3; O = V(OSiR3)3 (R = Me, Ph) undergoes a reaction with Lawesson reagent to yield dithiophosphonate complexes.All compounds obtained are characterized by 1H and 51V NMR spectroscopy; the stability of thiovanadium(V) compounds is discussed.V(StC4H9)4 has been sythesized as a first example of vanadium(IV) thiolates. - Key words: Thiolato Oxovanadium(V), Thiolato Thiovanadium(V), Preparation, 51V NMR Spectra
- Preuss, Fritz,Noichl, Harald
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p. 121 - 129
(2007/10/02)
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- CLAY-SUPPORTED REAGENTS IV. A NOVEL COUPLING OF THIOLS INTO DISULPHIDES, VIA THIONITRITE INTERMEDIATES USING A CLAY-SUPPORTED NITROSATION REAGENT.
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Thiols are converted into symmetrical disulphides, under very mild conditions, by bentonite-supported Fe(NO3)3*H2O.
- Cornelis, Andre,Depaye, Nicole,Gerstmans, Andre,Laszlo, Pierre
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p. 3103 - 3106
(2007/10/02)
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- In Search of New Sulfur Transfer Agents
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The chemistry of various sulfur-transfer agents is studied.The reaction of aromatic sulfenyl chloride 5 in the presence of imidazole and/or triethylamine gives the aryl disulfides 7 in 14-85 percent yield, whereas in the case of the corresponding benzylsulfenyl chlorides 9 in the presence of triethylamine and/or caprolactam, both disulfide 10 and benzyl chlorides 11 are formed in 0-81 precent and 10-72 precent yield, respectively. - The transfer reactions of 3-sulfenylated hydantoins 18 with amines are useful for the preparation of the unsymmetric sulfenamides 20 in 31 -61 percent yield.Analogous transfer reactions of compounds 23 and 24 with piperidine give N,N'-thiodipiperidine (3, X = CH2) in 71-80 percent.
- Sosnovsky, George,Krogh, James A.
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p. 121 - 136
(2007/10/02)
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