The structure-activity relationship between the metal center and regio-selectivity is persistently a pivotal scientific issue. To address this, we select the 2-phenylpyridine sulfonylation reactions catalyzed by ruthenium and palladium as research subjects. An extensive theoretical study has been conducted on their reaction mechanisms, the sources of regio-selectivity, and the evolution of electronic structures. The distinct electronic structures lead to completely different catalytic mechanisms and electronic structure evolution processes for ruthenium and palladium. Ruthenium tends to form six-coordinate octahedral complexes, thus undergoing an inner-sphere redox active Ru(II)-Ru(III)-Ru(IV)-Ru(II) catalytic cycle. In contrast, palladium tends to form four-coordinate planar quadrilateral complexes, hence undergoing an outer-sphere redox neutral Pd(II) catalytic cycle. The distinct electronic structure evolution processes fundamentally differentiate the radical attack modes in the sulfonation process, thereby determining the regio-selectivity of the reaction. In the Ru-catalyzed system, the meta-selectivity arises mainly from a more stable Schrock carbene-type meta-intermediate. For the Pd-catalyzed system, the ortho-selectivity mainly comes from the stabilizing effect of the Pd(II) center on the single electron. This study provides novel insights into how the electronic structure of metal centers influences the reaction mechanism and selectivity, making a theoretical contribution to a deeper comprehension of the mechanism and regio-selectivity underlying aromatic functionalization reactions.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.joc.4c01940 | DOI Listing |
Cell Rep
January 2025
State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China. Electronic address:
Sterols target sterol-sensing domain (SSD) proteins to lower cholesterol and circulating and hepatic triglyceride levels, but the mechanism remains unclear. In this study, we identify acyl-coenzyme A (CoA) synthetase long-chain family member 1 (ACSL1) as a direct target of ergosterol (ES). The C-terminal domain of ACSL1 undergoes conformational changes from closed to open, and ES may target the drug-binding pocket in the acetyl-CoA synthetase-like domain 1 (ASLD1) of ACSL1 to stabilize the closed conformation and maintain its activity.
View Article and Find Full Text PDFSci Rep
January 2025
Saint Petersburg State University, St. Petersburg, 198504, Russia.
Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), an experimental and theoretical study of changes in the electronic structure (dispersion dependencies) and corresponding modification of the energy band gap at the Dirac point (DP) for topological insulator (TI) [Formula: see text] have been carried out with gradual replacement of magnetic Mn atoms by non-magnetic Ge atoms when concentration of the latter was varied from 10% to 75%. It was shown that when Ge concentration increases, the bulk band gap decreases and reaches zero plateau in the concentration range of 45-60% while trivial surface states (TrSS) are present and exhibit an energy splitting of 100 and 70 meV in different types of measurements. It was also shown that TSS disappear from the measured band dispersions at a Ge concentration of about 40%.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, P. R. China.
Photoluminescence is one of the most intriguing properties of metal nanoclusters derived from their molecular-like electronic structure, however, achieving high photoluminescence quantum yield (PLQY) of metal core-dictated fluorescence remains a formidable challenge. Here, we report efficient suppression of the total structural vibrations and rotations, and management of the pathways and rates of the electron transfer dynamics to boost a near-unity absolute PLQY, by decorating progressive addition of cations. Specifically, with the sequential addition of Zn, Ag, and Tb into the 3-mercaptopropionic acids capped Au nanoclusters (NCs), the low-frequency vibration of the metal core progressively decreases from 144.
View Article and Find Full Text PDFTrends Microbiol
January 2025
Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, London, UK; Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK. Electronic address:
Within both abiotic and host environments, bacteria typically exist as diverse, multispecies communities and have crucial roles in human health, agriculture, and industry. In these communities, bacteria compete for resources, and these competitive interactions can shape the overall population structure and community function. Studying bacterial community dynamics requires experimental model systems that capture the different interaction networks between bacteria and their surroundings.
View Article and Find Full Text PDFISA Trans
January 2025
Leuphana University of Lueneburg, Universitaetsallee 1, 21335 Lueneburg, Germany. Electronic address:
This paper addresses a non-interacting torque control strategy to decouple the d- and q-axis dynamics of a permanent magnet synchronous machine (PMSM). The maximum torque per ampere (MTPA) method is used to determine the reference currents for the desired torque. To realize the noninteracting control, knowledge concerning the inductances L and L of the electrical machine is necessary.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!