Valence Of Cu Research Articles

Revealing the contribution of Cu(II) and Cu(I) inherent in MOF-199 for efficient thiophene removal at room temperature

Thiophene (C4H4S) removal from coke oven gas is critical to its subsequent high valuable utilization but remains a challenge. MOF-199 was considered as a promising candidate for C4H4S adsorption removal owing to its nature of enriched opened Cu sites. However, the presence of mixed valence of Cu(II) and Cu(I) in MOF-199 makes it puzzling to their respective contribution to the removal of C4H4S. Herein, a series of MOF-199 with different Cu(I) contents were synthesized using different methods, including hydrothermal, solution diffusion, and ultrasonic, and their C4H4S adsorption performance were investigated. The respective contributions of Cu(II) and Cu(I) to the C4H4S removal was systematically discussed. The collected results indicated that although the samples prepared with different methods present a remarkable difference in textural characters, the latter was found to have a negligible influence on the C4H4S removal owing to MOF-199(H) affording an inferior surface area and pore volumes but performing the best C4H4S removal capacity of 53.7 mg S/g. The co-adsorption results of CH3SCH3 and C4H4S indicated that the excellent performance of MOF-199(H) mainly attributed to the presence of Cu(I), which provides active sites for C4H4S adsorption through π complex coordination. Cu(II) species was also found to the C4H4S adsorption via soft-acid-base coordinated interaction, but its contribution is 8.3 mg S/g, only accounting for 15.5 %. Additionally, the adsorption of C4H4S on MOF-199(H) was found to follow the intra-particle diffusion model and the Langmuir models. Moreover, MOF-199(H) also exhibited an excellent regeneration performance due to the weak interaction between C4H4S and their opened Cu sites, the C4H4S adsorption capacity still reaches 50.6 mg S/g after three regeneration cycles, about 94 % of its initial value. The results collected in this study will provide new insights for the manipulation of performance of C4H4S adsorption on the MOF-199.

CuCoO2 Nanoparticles as a Nanoprotease for Selective Proteolysis with High Efficiency at Room Temperature

AbstractMany nanoproteases contain tetravalent metal ions and catalyze peptide‐bond hydrolysis only at high temperature (60 °C). Here, we report a new and effective strategy to explore nanoproteases from nanoparticles containing low valent metal ions. We found that flower‐like CuCoO2 nanoparticles (CuCoO2 NPs) containing low valent Cu+ possessed excellent catalytic activity towards selective cleavage of peptide bonds with hydrophobic residues in bovine serum albumin (BSA) at room temperature. CuCoO2 NPs exhibited excellent stability and had great reusability. CuCoO2 NPs also hydrolyzed heat‐denatured and surfactant‐denatured BSA. Mechanism analysis revealed that the high Lewis acidity of Co3+ and the low valence of Cu+ were both essential for the high protease activity of CuCoO2 NPs. The flower‐like structure of CuCoO2 NPs and the strong nucleophilicity of Cu+‐bound hydroxyl endow them with excellent catalytic performance. The findings open a new way for the design and discovery of high‐efficiency nanoproteases.

CuCoO2 Nanoparticles as a Nanoprotease for Selective Proteolysis with High Efficiency at Room Temperature.

Many nanoproteases contain tetravalent metal ions and catalyze peptide-bond hydrolysis only at high temperature (60 °C). Here, we report a new and effective strategy to explore nanoproteases from the nanoparticles containing low valent metal ions. We found that flower-like CuCoO2 nanoparticles (CuCoO2 NPs) containing low valent Cu+ possessed excellent catalytic activity towards selective cleavage of peptide bonds with hydrophobic residues in bovine serum albumin (BSA) at room temperature. CuCoO2 NPs exhibited excellent stability and had great reuse performance. CuCoO2 NPs also hydrolyzed heat-denatured and surfactant-denatured BSA. Mechanism analysis revealed that the high Lewis acidity of Co3+ and the low valence of Cu+ were both essential for the high protease activity of CuCoO2 NPs. The flower-like structure of CuCoO2 NPs and the strong nucleophilicity of Cu+-bound hydroxyl endue them with excellent catalytic performance. The findings open a new way for design and discovery of high-efficiency nanoproteases.

Well-dispersed Cu[sbnd]Fe doping nanoparticles with mixed valence in carbon aerogel as effective adsorbent for H2S removal at low temperature

In order to overcome the deficiencies of low adsorption capacity and poor tolerance to high space velocities of commercial adsorbents for H2S removal, core-shell structured Cu-Fe/carbon aerogels (CA) with mixed valence of Cu and Fe were synthesized. The doping of Cu decreased the average size of Fe nanoparticles and enhanced the dispersion of nanoparticles. In addition, parts of oxides were reduced to Cu0 and Fe0 by carbon shell during carbonization process, resulting in the coexistence of mixed valence CuFe doped nanoparticles in CA. The existence of Cu0 and Fe0 nanoparticles is the key contributor for excellent tolerance to high space velocities, where the H2S could be easily adsorbed and dissociated to form reactive intermediate such as HS− and S2−. The well dispersed CuFe doping oxides are the active sites for H2S capture, benefiting for the high H2S adsorption capacity. The adsorbed water can be dissociated to hydroxyl groups over iron oxide, which is more conducive to the removal of H2S. The H2S (200 ppm H2S in CH4) adsorption capacity of optimized adsorbent was 221.1 mg∙g−1 at 100% relative humidity. This study provided a new insight into the synthesis of Cu-based and Fe-based adsorbents for the removal of H2S.

The synthesis and highly effective antibacterial properties of Cu-3, 5-dimethy l-1, 2, 4-triazole metal organic frameworks.

The influence of metal ions, the state of metal salt, and ligands on the sterilization ability of (Metalorganic frameworks) MOFs to effectively achieve sterilization has been investigated in this study. Initially, the MOFs were synthesized by elements of Zn, Ag, and Cd for the same periodic and main group of Cu. This illustrated that the atomic structure of Cu was more beneficial for coordinating with ligands. To further induce the maximum amount of Cu2+ ions in the Cu-MOFs to achieve the highest sterilization, various Cu-MOFs synthesized by the different valences of Cu, various states of copper salts, and organic ligands were performed, respectively. The results demonstrated that Cu-MOFs synthesized by 3, 5-dimethyl-1, 2, 4-triazole and tetrakis (acetonitrile) copper(I) tetrafluoroborate presented the largest inhibition-zone diameter of 40.17mm towards Staphylococcus Aureus (S. aureus) under dark conditions. The proposed mechanism of Cu (Ⅱ) in MOFs could significantly cause multiple toxic effects, such as the generation of reactive oxygen species, and lipid peroxidation in S. aureus cells, when the bacteria was anchored by the Cu-MOFs via electrostatic interaction. Finally, the broad antimicrobial properties of Cu-MOFs against Escherichia coli (E. coli), Acinetobacter baumannii (A. baumannii), and S. aureus were demonstrated. In conclusion, the Cu-3, 5-dimethyl-1, 2, 4-triazole MOFs appeared to be potential antibacterial catalysts in the antimicrobial field.

Electron-transfer pathways insights into contaminants oxidized by [tbnd]Cu-OOSO3- intermediate: Effects of oxidation states of Cu and solution pH values

The copper-peroxy complex (Cu-OOSO3-) metastable intermediate has been confirmed to oxidize contaminants via a single-electron-transfer pathway or an oxygen-atom-transfer pathway. And the effects of Cu oxidation states and reaction pH conditions on the intermediate properties have not been explored in depth. Here, copper oxide (CuOx) catalysts with different Cu oxidation states were synthesized by a simple precipitation method by controlling the reaction temperature from 0 to 45 °C. CuOx displayed a strong catalytic dependence on the Cu oxidation state, and CuOx-30 with Cu average valence on the catalyst surface of 1.61 was more reactive for catalytic degradation of bisphenol A with peroxymonosulfate (PMS). Notably, CuOx-30, with the best electron-accepting ability, was easier to bonding with PMS to form the Cu-OOSO3- reactive complex, and the generated intermediate exhibited the strongest capacity to obtain electrons from contaminants. Moreover, the electron-transfer pathways were closely related to the average valence of Cu, and the contribution of the oxygen-atom-transfer pathway changed volcanic with increasing Cu valence. Meanwhile, the reaction predominantly involved the oxygen-atom-transfer pathway under acidic conditions (pH=3), while the contribution of the single-electron-transfer pathway raised with increasing pH values. Hence, this work was devoted to providing new insights into the CuOx-inducing PMS activation and vital supplementary to the properties of the Cu-OOSO3- intermediate.

Influence of charged walls and defects on DC resistivity and dielectric relaxations in Cu-Cl boracite

Charged domain walls form spontaneously in Cu-Cl boracite on cooling through the phase transition. These walls exhibit changed conductivity compared to the bulk and motion consistent with the existence of negative capacitance. Here, we present the dielectric permittivity and DC resistivity of bulk Cu-Cl boracite as a function of temperature (−140 to 150 °C) and frequency (1 mHz to 10 MHz). The thermal behavior of the two observed dielectric relaxations and the DC resistivity is discussed. We propose that the relaxations can be explained by the existence of point defects, most likely local complexes created by a change of valence of Cu and accompanying oxygen vacancies. In addition, the sudden change in resistivity seen at the phase transition suggests that conductive domain walls contribute significantly to the conductivity in the ferroelectric phase.

Antiferromagnetic Order and Spin-Canting Transition in the Corrugated Square Net Compound Cu3(TeO4)(SO4)·H2O.

Strongly correlated electrons in layered perovskite structures have been the birthplace of high-temperature superconductivity, spin liquids, and quantum criticality. Specifically, the cuprate materials with layered structures made of corner-sharing square-planar CuO4 units have been intensely studied due to their Mott insulating ground state, which leads to high-temperature superconductivity upon doping. Identifying new compounds with similar lattice and electronic structures has become a challenge in solid-state chemistry. Here, we report the hydrothermal crystal growth of a new copper tellurite sulfate, Cu3(TeO4)(SO4)·H2O, a promising alternative to layered perovskites. The orthorhombic phase (space group Pnma) is made of corrugated layers of corner-sharing CuO4 square-planar units that are edge-shared with TeO4 units. The layers are linked by slabs of corner-sharing CuO4 and SO4. Using both the bond valence sum analysis and magnetization data, we find purely Cu2+ ions within the layers but a mixed valence of Cu2+/Cu+ between the layers. Cu3(TeO4)(SO4)·H2O undergoes an antiferromagnetic transition at TN = 67 K marked by a peak in the magnetic susceptibility. Upon further cooling, a spin-canting transition occurs at T* = 12 K, evidenced by a kink in the heat capacity. The spin-canting transition is explained on the basis of a J1-J2 model of magnetic interactions, which is consistent with the slightly different in-plane superexchange paths. We present Cu3(TeO4)(SO4)·H2O as a promising platform for the future doping and strain experiments that could tune the Mott insulating ground state into superconducting or spin liquid states.

Remodeling endogenous H2S microenvironment in colon cancer to enhance chemodynamic therapy

Chemodynamic therapy (CDT) is a newly emerged, minimally invasive treatment with high selectivity, few side effects, and good prospects for clinical application. However, CDT does not effectively inhibit the growth of colon cancer, which has a strongly reducing tumor microenvironment owing to a high endogenous expression of H2S. To overcome this limitation, a new strategy is proposed to enhance the CDT of colon cancer by remodeling the microenvironment through depletion of endogenous H2S by CuFe2O4 nanoparticles. After H2S depletion, the valence of Cu (II) and Fe (III) in CuFe2O4 particles is reduced to Cu (I) and Fe (II) and photothermal properties of the nanoparticles are activated, both these effects enhance CDT. Further, in vitro and in vivo results demonstrate that endogenous H2S depletion by CuFe2O4 particles induced three effects that synergistically enhanced the performance of CDT. In this study, the development of a new strategy to enhance the CDT of colon cancer is reported.

The effective and stable Cu–C@SiO2 catalyst for the syntheses of methanol and ethylene glycol via selective hydrogenation of ethylene carbonate

The co-production of ethylene glycol and methanol via ethylene carbonate hydrogenation derived from CO2 has attracted great concerns because of the promising chemical utilization of CO2 in large-scale. Copper-based catalysts are widely concerned in hydrogenation of ester due to the high catalytic efficiency and low cost, but the stability of copper-based catalyst is poor and needs to be further improved. In this study, the modification Cu–C@SiO2-R catalyst with graphite oxide was prepared by using Cu3(BTC)2 as the precursor and ammonia evaporation method, and was applied in ethylene carbonate hydrogenation to synthesis ethylene glycol and methanol. Furthermore, the catalysts were characterized in detail. The results showed that the Cu–C@SiO2-R catalyst was modified with graphite oxide, the average size of Cu particles was 2.9 nm and Cu particles had good dispersion. In addition, both Cu–C@SiO2-R and Cu@SiO2-R catalysts had similar ratio of Cu+/(Cu0+Cu+). In a batch reactor, under 453 K, 5 MPa, 4 h, the catalytic efficiency was 80.0% EC conversion 92.2% EG and 70.8% MeOH selectivity showing excellent catalytic performance capability of Cu–C@SiO2-R catalyst. In long-term experiment, the Cu–C@SiO2-R catalyst showed excellent stability after using for 264 h. The activity was 0.63 gEC gcat−1 h−1, and 100.0% EC conversion 99.9% EG and 85.8% MeOH selectivity could be achieved in a fixed bed. After the long-term experiment, the Cu+/(Cu++Cu0) ratio in Cu–C@SiO2-R catalyst kept at around 0.48. In contrast, the Cu+/(Cu++Cu0) ratio in Cu@SiO2-R catalyst decreased sharply from 0.48 to 0.38. The stability of the structure and the balance of valence of Cu were considered to be responsible to the stability of Cu–C@SiO2-R catalyst, because the graphite oxide not only kept the Cu+/(Cu0+Cu+) ratio stability, but also restrained the aggregation of Cu particles and loss of copper. This work provides an in-depth understanding of the stabilization mechanism of Cu and can be a reference for the industrial application of ethylene carbonate hydrogenation.

Aging characteristic of Cu-doped nickel manganite NTC ceramics

The drift in electrical properties (e. g., the resistivity and B-value) is vital to the practical application for negative temperature coefficient (NTC) ceramics. In this work, Cu-doped nickel manganite ceramics were prepared by solid-state method, to investigate the degradation mechanism of both the resistivity and B-value. Results showed that the as-prepared ceramics exhibited typical NTC characteristics with cubic spinel phase, and that Cu doping greatly reduced the resistivity and B-value. However, the increase of Cu content in system aggravated the drift in the resistivity and B-value after the samples were aged at 300 °C for 30 h. XPS was carried out to further clarify the change in electrical properties. It was found that the decline of properties was due to the decrease of Mn4+ content in system after aging, which derived from the increase of chemical valence of Cu.

High-pressure synthesis of heavily hole-doped cuprates Mg1−xLixCu2O3 with quasi-one-dimensional structure

We investigate electronic properties of hole-doped cuprates ${\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ with the quasi-one-dimensional two-leg-ladder structure. We succeeded in extending the solubility limit of Li in ${\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ from $x=0.12$ to $x=0.60$ by using the high-pressure synthesis technique. The antiferromagnetic transition temperature rapidly decreases with increasing Li content from 94 K at $x=0$ to 7.5 K at $x=0.30$, and takes an almost constant value (3--6 K) at $x\ensuremath{\ge}0.35$. The antiferromagnetic order still exists even at $x=0.60$, where the formal valence of Cu is as large as $+2.30$. The temperature dependence of the specific heat suggests the finite contribution of the electronic specific heat at $x=0.20--0.60$, which is consistent with high valence of Cu. Nevertheless, the temperature dependence of resistivity shows a variable range hopping behavior in the whole $x$ ranges, and the insulating behavior survives under the pressure up to 2.9 GPa. This peculiar behavior is owing to the disorder originating from the intersite atom exchanges due to the similar ionic radius of cations in ${\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$. Nonmagnetic ions of ${\mathrm{Mg}}^{2+}$ and ${\mathrm{Li}}^{+}$ are introduced into the ${\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ planes of ${\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$, resulting in the localization of doped hole carriers.

The Optoelectronic Properties of p-Type Cr-Deficient Cu[Cr0.95-xMg0.05]O2 Films Deposited by Reactive Magnetron Sputtering.

CuCrO2 is one of the most promising p-type transparent conductive oxide (TCO) materials. Its electrical properties can be considerably improved by Mg doping. In this work, Cr-deficient CuCrO2 thin films were deposited by reactive magnetron sputtering based on 5 at.% Mg doping. The influence of Cr deficiency on the film’s optoelectronic properties was investigated. As the film’s composition varied, CuO impurity phases appeared in the film. The mixed valency of Cu+/Cu2+ led to an enhancement of the hybridization between the Cu3d and O2p orbitals, which further reduced the localization of the holes by oxygen. As a result, the carrier concentration significantly improved. However, since the impurity phase of CuO introduced more grain boundaries in Cu[Cr0.95−xMg0.05]O2, impeding the transport of the carrier and incident light in the film, the carrier mobility and the film’s transmittance reduced accordingly. In this work, the optimal optoelectronic performance is realized where the film’s composition is Cu[Cr0.78Mg0.05]O2. Its Haacke’s figure of merit is about 1.23 × 10−7 Ω−1.

Preparation of Mn2+‐Cu+ co‐doped P2O5–ZnO–Al2O3 glasses and their red fluorescence properties

AbstractTo make a Mn2+‐doped red glass phosphor that can be excited with ultraviolet (UV) light of light‐emitting diodes (LEDs), 60P2O5‐35ZnO‐5Al2O3‐8MnO‐xCu2O glasses (x = 0‐1.00) were prepared by a melt‐quenching method at 1200‐1400°C for 30‐180 minutes in atmospheric air, and the redox of Mn and Cu as well as fluorescence properties were investigated. The Mn2+ ion was not reduced and oxidized in the melting, quenching, and annealing processes. The valence of Cu in the glasses changed in the order of 0, 1+, and 2+ with the increase in the amount of Cu2O and in the melting temperature and time. In this study, a 60P2O5‐35ZnO‐5Al2O3‐8MnO‐0.10Cu2O glass melted at 1250°C for 90 minutes, having the highest Cu+ concentration, showed the strongest Mn2+ red fluorescence under the UV light at 275 nm. This strong Mn2+ red fluorescence has been caused by the energy transfer from excited Cu+ ions to Mn2+ ions.

Synthesis and structural characterization of a superconducting GdSr2RuCu2O8−δ single crystal grown by partial melting

We successfully synthesized a superconducting GdSr2RuCu2O8−δ (RuGd-1212) single crystal via the partial melting technique. Structural analysis of this crystal indicated the substitution of Cu and Gd at the Ru and Sr sites, respectively. The disappearance of superconductivity in non-superconducting samples could be attributed to the substitution of Ru in the CuO2 planes and/or Gd at the Sr sites. The distance between the CuO2 planes in the superconducting RuGd-1212 single crystal was shorter, indicating that the valence of Cu in the CuO2 plane had decreased. A superconducting transition with Tc-onset of 23.0 K and Tc-zero of 6.2 K was observed.

Two new coordination polymers based on a pyridine-pyrazole bifunctional linker: Synthesis, structure and luminescent properties

The solvothermal reaction of CdCl2 or CuCl2 with a pyridine-pyrazole bifunctional ligand 3,5‑diethyl‑4‑(4‑pyridyl)‑pyrazole (Hdeppz) under different solvents afforded two coordination polymers [Cd(Hdeppz)2(Cl)2]n (1) and [Cu4ICuII(deppz)4(Cl)2]n (2), respectively. Owing to different coordinated modes of Hdeppz and metal ions, 1 and 2 display different grid layer structures. In 1, the neutral Hdeppz ligand behaves as a linear linker to connect two Cd2+ ions, while 2 contains not only the Y-shaped deppz linker but also the mixed valence of Cu+ and Cu2+ ions. Meanwhile, an uncommon Cu4(pz)4 metallocyclic unit is formed in 2, and which further produces an unprecedented (CuIICl2CuI4)n supramolecular chain by Cu···Cl interactions. The strong solid-state blue-green luminescence was also observed in 1.

Copper Sulfide Nanocrystals with Tunable Composition by Reduction of Covellite Nanocrystals with Cu+ Ions

Platelet-shaped copper sulfide nanocrystals (NCs) with tunable Cu stoichiometry were prepared from Cu-rich covellite (Cu1.1S) nanoplates through their reaction with a Cu(I) complex ([Cu(CH3CN)4]PF6) at room temperature. Starting from a common sample, by this approach it is possible to access a range of compositions in these NCs, varying from Cu1.1S up to Cu2S, each characterized by a different optical response: from the metallic covellite, with a high density of free carriers and strong localized surface plasmon resonance (LSPR), up to Cu2S NCs with no LSPR. In all these NCs the valency of Cu in the lattice stays always close to +1, while the average -1 valency of S in covellite gradually evolves to -2 with increasing Cu content; i.e., sulfur is progressively reduced. The addition of copper to the starting covellite NCs is similar to the intercalation of metal species in layered transition metal dichalcogenides (TMDCs); i.e., the chalcogen-chalcogen bonds holding the layers are progressively broken to make room for the intercalated metals, while their overall anion sublattice does not change much. However, differently from the TMDCs, the intercalation in covellite NCs is sustained by a change in the redox state of the anion framework. Furthermore, the amount of Cu incorporated in the NCs upon reaction is associated with the formation of an equimolar amount of Cu(II) species in solution. Therefore, the reaction scheme can be written as: Cu1.1S + 2γCu(I) → Cu1.1+γS + γCu(II).

Synthesis and reaction pathway investigation of chalcopyrite CuInSe2 nanoparticles for one-pot method

Highly dispersed and near stoichiometric chalcopyrite CuInSe2 nanoparticles were successfully synthesized via a facile and rapid one-pot method. For understanding the reaction pathway, the solid intermediates obtained at different stages of CuInSe2 nanoparticles synthesis process were investigated in detail by powder X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), energy dispersive spectroscopy (EDS) and Raman spectroscopy. The XRD patterns showed that the phase formation sequence was CuSe→CuInSe2. The XPS results indicated that the valences of Cu and Se in CuSe were +1 and −1, respectively. The chemical composition of the solid intermediates revealed the presence of the solid-state In–Se secondary phases in the synthesis process. However, no XRD signals or Raman signals of the solid-state In–Se secondary phase were observed. Based on the experimental results, the possible reaction pathway was proposed.

Structural and Magnetic Studies of Zn Doped LaRh<sub>1-2x</sub>Cu<sub>2x</sub>O<sub>3</sub>

Two series of Zn doped Rh perovskites LaRh1-2xCux ZnxO3 and La0.75Pb0.25Rh1-2xCuxZnxO3 (0≤ x ≤0.25) were synthesised by solid-state methods and their crystallographic, magnetic, and electric properties investigated. Both series have an orthorhombic perovskite-type structure in space group Pbnm. The increase in Zn content has an obvious impact on the electron delocalisation in which the shift in the average valency of Cu and Rh (+2.5 and +3.5) has resulted in a reduction in cell volumes and an increase in the effective magnetic moments. The Curie–Weiss magnetization curves measured between 5-300K are indicative of antiferromagnetism. The addition of Pb to the A- site decreases the conductivity as anticipated.

Mechanical Probes of SOD1 Predict Systematic Trends in Metal and Dimer Affinity of ALS-Associated Mutants

Mutations and oxidative modification in the protein Cu,Zn superoxide dismutase (SOD1) have been implicated in the death of motor neurons in amyotrophic lateral sclerosis (ALS), a presently incurable, invariably fatal neurodegenerative disease. Here we employ steered, all-atom molecular dynamics simulations in implicit solvent to investigate the significance of either mutations or post-translational modifications (PTMs) to SOD1 on metal affinity, dimer stability, and mechanical malleability. The work required to induce moderate structural deformations as a function of sequence index constitutes a “mechanical fingerprint” measuring structural rigidity in the native basin, from which we are able to unambiguously distinguish wild-type SOD1 from PTM variants and measure the severity of a given PTM on structural integrity. The cumulative distribution of work values provided a way to cleanly discriminate between SOD1 variants. Disulfide reduction destabilizes dimer stability more than the removal of either metal, but not moreso than the removal of both metals. Intriguingly, we found that disulfide reduction mechanically stabilizes apo-SOD1 monomer, underscoring the differences between native basin mechanical properties and equilibrium thermodynamic stabilities and elucidating the presence of internal stress in the apo state. All PTMs and ALS-associated mutants studied showed an increased tendency to lose either Cu or Zn and to monomerize—processes known to be critical in the progression of ALS. The valence of Cu strongly modulates its binding free energy. As well, several mutants were more susceptible to loss of metals and monomerization than the disulfide-reduced or apo forms of SOD1. Distance constraints are required to calculate free energies for metal binding and dimer separation, which are validated using thermodynamic cycles. When distance constraints are removed, the results agree with those obtained from direct application of the Jarzynski equality.