The first demonstration of photochemical enediyne liberation from a metal complex has led to a new class of enediynes, the cyclopentadienidoenediynes, which are demonstrated to exist as air-stable solids with low ionization potentials and large dipole moments. NMR and IR spectroscopy, X-ray crystallography, and ab initio computations enable a comparison with the ubiquitous benzoenediynes.
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J Mol Model
January 2025
School of Chemistry & Chemical Engineering, Linyi University, Linyi, 276000, China.
Context: In this work, a comparative study on the catalytic conversion of 5-hydroxymethyl furfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) on precious Pd(111) and nonprecious Cu(111) was systematically performed. On the basis of the calculated activation energy (E) and reaction energy (E), the optimal energy path for the hydrogenation of HMF (F-CHO) into BHMF (F-CHOH) on Pd(111) is as follows: F-CHO + 2H → F-CHOH + H → F-CHOH; the minimum reaction path on Cu(111) is F-CHO + 2H → F-CHO + H → F-CHOH. On Cu(111), the formation of F-CHOH from F-CHO hydrogenation is the rate-determining step because it has the highest reaction energy barrier and the smallest rate constant.
View Article and Find Full Text PDFChem Sci
January 2025
Radioisotope Science and Technology Division, Oak Ridge National Laboratory Oak Ridge TN 37830 USA
Lanthanides (Ln) are typically found in the +3 oxidation state. However, in recent decades, their chemistry has been expanded to include the less stable +2 oxidation state across the entire series except promethium (Pm), facilitated by the coordination of ligands such as trimethylsilylcyclopentadienyl, CHSiMe (Cp'). The complexes have been the workhorse for the synthesis and theoretical study of the fundamental aspects of divalent lanthanide chemistry, where experimental and computational evidence have suggested the existence of different ground state (GS) configurations, 4f or 4f 5d, depending on the specific metal.
View Article and Find Full Text PDFNat Commun
January 2025
Institute for Materials Science, University of Stuttgart, D-70569, Stuttgart, Germany.
The knowledge of diffusion mechanisms in materials is crucial for predicting their high-temperature performance and stability, yet accurately capturing the underlying physics like thermal effects remains challenging. In particular, the origin of the experimentally observed non-Arrhenius diffusion behavior has remained elusive, largely due to the lack of effective computational tools. Here we propose an efficient ab initio framework to compute the Gibbs energy of the transition state in vacancy-mediated diffusion including the relevant thermal excitations at the density-functional-theory level.
View Article and Find Full Text PDFSci Data
January 2025
IBM Research, Hursley, SO21 2JN, UK.
A significant challenge in computational chemistry is developing approximations that accelerate ab initio methods while preserving accuracy. Machine learning interatomic potentials (MLIPs) have emerged as a promising solution for constructing atomistic potentials that can be transferred across different molecular and crystalline systems. Most MLIPs are trained only on energies and forces in vacuum, while an improved description of the potential energy surface could be achieved by including the curvature of the potential energy surface.
View Article and Find Full Text PDFInorg Chem
January 2025
Institute of Inorganic Chemistry, Czech Academy of Sciences, CZ, 250 68 Husinec-Řež, Czech Republic.
A series of -tricarbollides based on 10,11-X-7-MeN--7,8,9-CBH (X = H, Cl, Br, I) and their protonated, i.e. cationic, counterparts, which have an extra H-bridge over the B10-B11 vector in the open pentagonal belt, were prepared.
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