Synthesis and crystal structure of a dimeric cyclic copper(I)-aliphatic disulfide complex cyclo-di-.mu.-[bis[2-(N,N-dimethylamino)ethyl]disulfide]-dicopper(I) tetrafluoroborate

Ottersen, T.; Warner, Larry G.; Seff, K.

doi:10.1021/ic50138a023

Cited by 32 publications

(17 citation statements)

References 14 publications

(20 reference statements)

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“…We incline to a hypothesis that the intermediates detected in the studied reaction—and possibly also in other systems containing thiols and copper ions—are dicopper–disulfide complexes of the type Cu(I)–S–S–Cu(I). Although only limited information exists on the stability and properties of such complexes, several examples have been prepared and characterized [ 38 , 75 , 76 , 77 , 78 , 79 ]. Importantly, such complexes show UV/Vis spectra with shoulders around 300 nm, which are interpreted as a metal to ligand charge transfer (MLCT) from Cu(I) to disulfide, or as a disulfide absorption significantly red-shifted due to Cu complexation and/or a deviation of the CSSC dihedral angle from 90° [ 75 ].…”

Section: Discussionmentioning

confidence: 99%

Reaction of N-Acetylcysteine with Cu2+: Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols

Valent

Bednářová

Schreiber

et al. 2022

IJMS

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We studied the kinetics of the reaction of N-acetyl-l-cysteine (NAC or RSH) with cupric ions at an equimolar ratio of the reactants in aqueous acid solution (pH 1.4–2) using UV/Vis absorption and circular dichroism (CD) spectroscopies. Cu2+ showed a strong catalytic effect on the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical (ABTSr) consumption and autoxidation of NAC. Difference spectra revealed the formation of intermediates with absorption maxima at 233 and 302 nm (ε302/Cu > 8 × 103 M−1 cm−1) and two positive Cotton effects centered at 284 and 302 nm. These intermediates accumulate during the first, O2-independent, phase of the NAC autoxidation. The autocatalytic production of another chiral intermediate, characterized by two positive Cotton effects at 280 and 333 nm and an intense negative one at 305 nm, was observed in the second reaction phase. The intermediates are rapidly oxidized by added ABTSr; otherwise, they are stable for hours in the reaction solution, undergoing a slow pH- and O2-dependent photosensitive decay. The kinetic and spectral data are consistent with proposed structures of the intermediates as disulfide-bridged dicopper(I) complexes of types cis-/trans-CuI2(RS)2(RSSR) and CuI2(RSSR)2. The electronic transitions observed in the UV/Vis and CD spectra are tentatively attributed to Cu(I) → disulfide charge transfer with an interaction of the transition dipole moments (exciton coupling). The catalytic activity of the intermediates as potential O2 activators via Cu(II) peroxo-complexes is discussed. A mechanism for autocatalytic oxidation of Cu(I)–thiolates promoted by a growing electronically coupled –[CuI2(RSSR)]n– polymer is suggested. The obtained results are in line with other reported observations regarding copper-catalyzed autoxidation of thiols and provide new insight into these complicated, not yet fully understood systems. The proposed hypotheses point to the importance of the Cu(I)–disulfide interaction, which may have a profound impact on biological systems.

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Section: Discussionmentioning

confidence: 99%

Reaction of N-Acetylcysteine with Cu2+: Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols

Valent

Bednářová

Schreiber

et al. 2022

IJMS

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“…The UV/Vis spectrum of 1 [OTf] 2 in dichloromethane features an intense absorption band at 417 nm ( ε =8000 M −1 cm −1 ) (Figure 4, red lines) which possibly originates from a Cu I →S metal‐to‐ligand charge transfer (MLCT) transition 8a–c…”

Section: Methodsmentioning

confidence: 99%

A Halide‐Induced Copper(I) Disulfide/Copper(II) Thiolate Interconversion

et al. 2012

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“…Co-ordination through the negatively charged oxygen atom of the sulphinate group is also found in the monomeric 1 : 2 Cu(rr)-2-pyridylsulphinate complex. 6 The distances and geometry around O (3) indicate that there are two hydrogen bonds [0 (3) .…”

mentioning

confidence: 99%

Disulphide bond cleavage in a pyridine-containing disulphide–copper(II) system under aerobic conditions. X-Ray crystal structure analysis of the product, diaquabis{µ-2-[(2-pyridymethyl)-amino]ethylsulphinato-O}dicopper(II) dichloride

Odani¹,

Maruyama²,

Yamauchi³

et al. 1982

J. Chem. Soc., Chem. Commun.

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Synthesis and crystal structure of a dimeric cyclic copper(I)-aliphatic disulfide complex cyclo-di-.mu.-[bis[2-(N,N-dimethylamino)ethyl]disulfide]-dicopper(I) tetrafluoroborate

Cited by 32 publications

References 14 publications

Reaction of N-Acetylcysteine with Cu2+: Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols

Reaction of N-Acetylcysteine with Cu2+: Appearance of Intermediates with High Free Radical Scavenging Activity: Implications for Anti-/Pro-Oxidant Properties of Thiols

A Halide‐Induced Copper(I) Disulfide/Copper(II) Thiolate Interconversion

Disulphide bond cleavage in a pyridine-containing disulphide–copper(II) system under aerobic conditions. X-Ray crystal structure analysis of the product, diaquabis{µ-2-[(2-pyridymethyl)-amino]ethylsulphinato-O}dicopper(II) dichloride

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