Peculiar Differences between Two Copper Complexes Containing Similar Redox-Active Ligands: Density Functional and Multiconfigurational Calculations

Gerhards, Luca; Werr, Marco; Hübner, Olaf; Solov’yov, Ilia A.; Himmel, Hans-Jörg

doi:10.1021/acs.inorgchem.3c02949

Cited by 7 publications

(3 citation statements)

References 59 publications

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“…The author argued that some ligands are “suspect” due to the ambiguity of their electronic structure upon coordination to metal ions. In many instances, redox-active ligands are considered “non-innocent” because determining the oxidation state of the metal and the oxidation state of the ligand is not trivial. − For example, R‑X 5 + (which are structurally and spectroscopically described as cuprous complexes bound by quinone-like ligands) can be represented by three valence tautomers in which the Cu ion and the ligand scaffold adopt different oxidation states (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers

Wu,

Puri,

Qiu

et al. 2024

Inorg. Chem.

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Electron-coupled-proton buffers (ECPBs) store and deliver protons and electrons in a reversible fashion. We have recently reported an ECPB based on Cu and a redox-active ligand that promoted 4H + /4e − reversible transformations (J. Am. Chem. Soc. 2022, 144, 16905). Herein, we report a series of Cu-based ECPBs in which the ability of these to accept and/or donate H • equivalents can be tuned via ligand modification. The thermochemistry of the 4H + /4e − ECPB equilibrium was determined using open-circuit potential measurements. The reactivity of the ECPBs against proton-coupled electron transfer (PCET) reagents was also analyzed, and the results obtained were rationalized based on the thermochemical parameters. Experimental and computational analysis of the thermochemistry of the H + /e − transfers involved in the 4H + /4e − ECPB transformations found substantial differences between the stepwise (namely, BDFE 1 , BDFE 2 , BDFE 3 , and BDFE 4 ) and average bond dissociation free energy values (BDFE avg. ). Our analysis suggests that this "redox unleveling" is critical to promoting the disproportionation and ligand-exchange reactions involved in the 4H + /4e − ECPB equilibria. The difference in BDFE avg. within the series of Cu-based ECPBs was found to arise from a substantial change in the redox potential (E 1/2 ) upon modification of the ligand scaffold, which is not fully compensated for by a change in the acidity/basicity (pK a ), suggesting "thermochemical decompensation".

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Section: Resultsmentioning

confidence: 99%

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers

Wu,

Puri,

Qiu

et al. 2024

Inorg. Chem.

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“…Areas of Applications : DFT has found numerous applications in chemistry and materials science by calculating the electronic ground-state properties of various systems. ,− In solid-state calculations, the LDA is still commonly used along with plane-wave basis sets, as an electron-gas approach is more appropriate for electrons delocalized through an infinite solid. However, in calculations involving molecular systems, more accurate long-range corrected XC functionals ( e.g.…”

Section: Existing Theoretical and Computational Methods And Their Limitsmentioning

confidence: 99%

Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Solov’yov,

Verkhovtsev,

Mason

et al. 2024

Chem. Rev.

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This roadmap reviews the new, highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The Review highlights several recent advances in the field and provides a roadmap for the development of the field over the next decade. Condensed matter systems exposed to radiation can be inorganic, organic, or biological, finite or infinite, composed of different molecular species or materials, exist in different phases, and operate under different thermodynamic conditions. Many of the key phenomena related to the behavior of irradiated systems are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. The multiscale nature of such phenomena requires the quantitative description of the radiation-induced effects occurring at different spatial and temporal scales, ranging from the atomic to the macroscopic, and the interlinks between such descriptions. The multiscale nature of the effects and the similarity of their manifestation in systems of different origins necessarily bring together different disciplines, such as physics, chemistry, biology, materials science, nanoscience, and biomedical research, demonstrating the numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications.

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“…Redox-active ligands are easily oxidized or reduced, compared to classic spectator ligands, extending the redox reactivity of metal atoms. Normally, the number of electrons that a mononuclear metal complex can transfer to a substrate is limited to one or two, but in complexes with active redox ligands, the ligands can provide additional electrons [7].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid

Castiñeiras,

Fernández-Hermida,

García-Santos

et al. 2024

Molecules

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The reaction between 5-acetylbarbituric acid and 4-dimethylthiosemicarbazide or 4-hexamethyleneiminyl thiosemicarbazide produces 5-acetylbarbituric-4-dimethylthiosemicarbazone (H2AcbDM) and 5-acetylbarbituric-4N-hexamethyleneiminyl thiosemicarbazone (H2Acbhexim). Eight new complexes with different copper(II) salts have been prepared and characterized using elemental analysis, molar conductance, UV–Vis, ESI-HRMS, FT-IR, magnetic moment, EPR, and cyclic voltammetry. In addition, three-dimensional molecular structures of [Cu(HAcbDM)(H2O)2](NO3)·H2O (3a), [Cu(HAcbDM)(H2O)2]ClO4 (4), and [Cu(HAcbHexim)Cl] (6) were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out. The H-bonded assemblies were further studied energetically using DFT calculations and MEP surface and QTAIM analyses. In these complexes, the thiosemicarbazone coordinates to the metal ion in an ONS-tridentate manner, in the O-enolate/S-thione form. The electrochemical behavior of the thiosemicarbazones and their copper(II) complexes has been investigated at room temperature using the cyclic voltammetry technique in DMFA. The Cu(II)/Cu(I) redox system was found to be consistent with the quasi-reversible diffusion-controlled process.

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Peculiar Differences between Two Copper Complexes Containing Similar Redox-Active Ligands: Density Functional and Multiconfigurational Calculations

Cited by 7 publications

References 59 publications

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers

Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid

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Peculiar Differences between Two Copper Complexes Containing Similar Redox-Active Ligands: Density Functional and Multiconfigurational Calculations

Cited by 7 publications

References 59 publications

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H+/4e– Electron-Coupled-Proton Buffers

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H+/4e– Electron-Coupled-Proton Buffers

Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid

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Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers

Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H⁺/4e^– Electron-Coupled-Proton Buffers