Photosynthetic oxygen-evolving center (OEC), the "engine of life", is a unique MnCaO cluster catalyzing the water oxidation. The role of redox-inactive component Ca, which can only be functionally replaced by Sr in a biological environment, has been under debate for a long time. Recently, its modulating effect on the redox potential of native OEC and artificial structural OEC model complex has received great attention, and linear relationship between the potential and the Lewis acidity of the redox-inactive metal has been proposed for the MMnO model complex. In this work, the modulating effect has been studied in detail using the MnCaO model complex, which is the closest structural model to OEC to date and has a similar redox potential at the S-S transition. We found the redox-inactive metal only has a weak modulating effect on the potential, which is comparable in strength to that of the ligand environments. Meanwhile, the net charge of the complex, which could be changed along with the redox-inactive metal, has a high impact on the potential and can be unified by protonation, deprotonation, or ligand modification. Although the modulating effect of the redox-inactive metal is not very strong, the linear relationship between the potential and the Lewis acidity is still valid for MnMO complexes. Our results of strong modulating effects for net charge and weak modulating effects for redox-inactive metal fit with the previous experimental observations on MnMO (M = Ca, Y, and Gd) model complexes, and suggest that Ca can be structurally and electrochemically replaced with other metal cations, together with proper ligand modifications.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.inorgchem.2c00243 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Contributions of Both the Eastman Entropy of Transfer and Electric Double Layer to the Electromotive Force of Ionic Thermoelectric Supercapacitors.
ACS Appl Mater Interfaces
January 2025
Global Zero Emission Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
Recently, ionic thermoelectric supercapacitors have gained attention because of their high open circuit voltages, even for ions that are redox inactive. As a source of open circuit voltage (electromotive force), an asymmetry in electric double layers developed by the adsorption of ions at the electrode surfaces kept at different temperatures has previously been proposed. As another source, the Eastman entropy of transfer, which is related to the Soret coefficient, has been considered.
View Article and Find Full Text PDFTunability in Heterobimetallic Complexes Featuring an Acyclic "Tiara" Polyether Motif.
Inorg Chem
January 2025
Department of Chemistry, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States.
Both cyclic "crown" and acyclic "tiara" polyethers have been recognized as useful for the binding of metal cations and enabling the assembly of multimetallic complexes. However, the properties of heterobimetallic complexes built upon acyclic polyethers have received less attention than they deserve. Here, the synthesis and characterization of a family of eight redox-active heterobimetallic complexes that pair a nickel center with secondary redox-inactive cations (K, Na, Li, Sr, Ca, Zn, La, and Lu) bound in acyclic polyether "tiara" moieties are reported.
View Article and Find Full Text PDFUse of Intramolecular Quinol Redox Couples to Facilitate the Catalytic Transformation of O and O-Derived Species.
Acc Chem Res
January 2025
Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States.
ConspectusThe redox reactivity of transition metal centers can be augmented by nearby redox-active inorganic or organic moieties. In some cases, these functional groups can even allow a metal center to participate in reactions that were previously inaccessible to both the metal center and the functional group by themselves. Our research groups have been synthesizing and characterizing coordination complexes with polydentate quinol-containing ligands.
View Article and Find Full Text PDFMetal ions-mediated concerted electron-proton transfer enables catalytic oxidation of phenolic contaminants by permanganate.
Water Res
January 2025
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. Electronic address:
Permanganate has been extensively applied in water treatment due to its ease of handling and high stability. However, the impact of common water constituents, especially metal ions, on permanganate oxidation is poorly understood. Here, we report that many redox-inactive metal ions, such as Ca, Mg, Zn, Cu, and Al, can enhance the reactivity of permanganate with phenolic compounds.
View Article and Find Full Text PDFProton vs Electron: The Dual Role of Redox-Inactive Metal Ions in Permanganate Oxidation Kinetics.
Environ Sci Technol
October 2024
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
Article Synopsis
- Researchers explored how six metal ions (Ca, Mg, Ni, Zn, Al, and Sc) in water affect the oxidation behavior of permanganate (Mn(VII)) when removing organic pollutants.
- These metal ions enhance Mn(VII)'s electron and oxygen transfer abilities while slowing down proton transfer, influenced by their Lewis acidity.
- The study also found that relationships between Mn(VII) and metal ions change its properties and efficiency in breaking down phenolic pollutants, especially at certain pH levels, suggesting ways to improve water treatment processes.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!