The electrochemistry and spectroelectrochemistry of [Cl(2)FeS(2)MS(2)FeCl(2)](n)()(-) clusters (where n = 2 for M = Mo and W and n = 3 for M = V; Ia,Ib, and Ic, respectively) and the dimetal complex [Cl(2)FeS(2)MoS(2)](2)(-) (IIIa) were examined in order to characterize the structures and properties of the one-electron-reduced complexes. A stable reduction product for Ia was observed spectroelectrochemically at -1.05 V, which could be oxidized back to the starting complex. Reduction at more negative potentials caused complete bleaching of the spectrum, and the starting complex could not be obtained by reoxidation. Similar behavior was observed for the tungsten complex, Ib, but the dimetal complex [Cl(2)FeS(2)WS(2)](2)(-) was formed upon reoxidation. Chemical and electrochemical reduction of Ia and Ib both led to the same products (IIa and IIb), but by different mechanisms. Borohydride reduction of Ia and Ib led to the initial formation of the dimetal complex, while the electrochemical reduction of Ia proceeded by way of the formation of [Cl(2)FeS(2)MoS(2)FeCl(2)](3)(-). Spectral changes were observed in the reduction of Ic, but they were not reversible. Resonance Raman spectroscopy of the reduced complexes was carried out in order to characterize the reduction product. Two polarized bands in the sulfur bridging region were observed in the resonance Raman spectra of electrochemically and chemically generated IIa and IIb. The relative intensities of these bands were dependent upon the excitation frequency. Reduction of Ic led to the loss of all resonance Raman bands. Reduction of IIIa gave rise to a complex (IVa) that was spectrally quite similar to IIa. These results, along with the previously reported result that the reduction complex was diamagnetic, indicate that the complex IIa is a dimeric species. The most likely structure consistent with these data is a Mo(2)Fe(2)S(4) cubane structure.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ic9603114 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Assembly of a Heterobimetallic Fe/Mn Cofactor in the -Aminobenzoate Synthase Chlamydia Protein Associating with Death Domains (CADD) Initiates Long-Range Radical Hole-Hopping.
Biochemistry
November 2024
Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.
Article Synopsis
- * CADD utilizes its own amino acids (tyrosine and lysine) and operates with a unique Fe/Mn cofactor instead of the typical iron cofactor found in similar enzymes, impacting its mechanism of action.
- * Advanced studies reveal how CADD's structure and active-site variants affect its metal ion preferences, indicating that a transient tyrosine radical is involved in initiating pABA synthesis.
Coinage metal(I) clusters supported by a 1,10-phenanthroline-phosphine: orange-to-NIR phosphorescence, metallophilic interactions and enhanced cytotoxicity.
Dalton Trans
November 2024
Nikolaev Institute of Inorganic Chemistry, SB RAS, 3, Lavrentiev Ave., 630090 Novosibirsk, Russia.
A series of small coinage metal(I) clusters has been selectively synthesized using 2-(diphenylphosphino)-1,10-phenanthroline (L), a new promising dimetal-binding -ligand (L). Its reaction with CuI yields the complex [CuL(μ-I)][CuI], while the treatment of L with Au(tht)Cl/Ag or Au(tht)Cl/Cu systems leads to the assembly of [AuAgLCl], [AuCuLCl], [CuAuL] and [AgAuL] clusters. Theoretical analysis revealed pronounced intermetallic close shell interactions in these di- and trinuclear ensembles.
View Article and Find Full Text PDFStructural characterization of tyrosinases and an update on human enzymes.
Enzymes
September 2024
Department of Agriculture, Department of Excellence, University of Naples Federico II, Palace of Portici, Piazza Carlo di Borbone, Portici NA, Italy. Electronic address:
Article Synopsis
- - Tyrosinase is a key enzyme in melanin production, influencing skin, hair, and eye color through its catalytic activity in converting L-tyrosine to L-dopaquinone.
- - The chapter discusses the three-dimensional structures and functions of tyrosinases from different sources, emphasizing their di-metal ion coordination and variations among species.
- - It also explores the implications of human tyrosinase variants and their inhibitors for developing treatments for hyperpigmentation, highlighting the potential of specific compounds like kojic acid and L-mimosine as effective inhibitors.
The complexed crystal structure of dihydropyrimidinase reveals a potential interactive link with the neurotransmitter γ-aminobutyric acid (GABA).
Biochem Biophys Res Commun
January 2024
Department of Biomedical Sciences, Chung Shan Medical University, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan; Department of Medical Research, Chung Shan Medical University Hospital, No.110, Sec.1, Chien-Kuo N. Rd., Taichung City, Taiwan. Electronic address:
Dihydropyrimidinase (DHPase) plays a crucial role in pyrimidine degradation, showcasing a broad substrate specificity that extends beyond pyrimidine catabolism, hinting at additional roles for this ancient enzyme. In this study, we solved the crystal structure of Pseudomonas aeruginosa DHPase (PaDHPase) complexed with the neurotransmitter γ-aminobutyric acid (GABA) at a resolution of 1.97 Å (PDB ID 8WQ9).
View Article and Find Full Text PDFInfluence of ligand variation on the deactivation process of metal-to-ligand charge transfer excited states in quadruply bonded dimolybdenum complexes.
Phys Chem Chem Phys
December 2023
School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P. R. China.
To explore the dynamics of metal-to-ligand charge transfer (MLCT) excited states involving covalently bonded dimetal units, a series of quadruply bonded dimolybdenum (Mo) complexes, namely, [Mo2]-ph, [Mo2]-naph, and [Mo2]-anth, were synthesized and characterized. Our investigations reveal a non-radiative process associated with the deactivation of the MLCT state into a low-lying dimetal-centered triplet state (Mo-δδ*), resulting in the populated MLCT states in these molecular systems exhibiting either extremely weak emission or being non-emissive. The influence of ligand variation on the dynamics of MLCT states was examined using femtosecond transient absorption spectroscopy, with deactivation time constants determined to be 1.
View Article and Find Full Text PDFWant 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!