Mechanistic Insight into Alkali‐Metal Mediation of Styrene Transfer Hydrogenation: A DFT Study DOI Creative Commons
Keelan M. Byrne, Stuart D. Robertson, Robert E. Mulvey

et al.

ChemCatChem, Journal Year: 2024, Volume and Issue: unknown

Published: June 18, 2024

Abstract A computational mechanistic study was performed to investigate the transfer hydrogenation of styrene catalysed by a potassium tris‐hexamethyldisilazide magnesiate in presence 1,4‐cyclohexadiene. Exploiting cooperative effects between Mg and K centres present this tris(amide) complex results selective formation desired product ethylbenzene. The calculations demonstrate synergy metal within bimetallic complex, since neither monometallic amide K(HMDS) nor magnesium Mg(HMDS) 2 on their own can efficiently execute transformation under experimental conditions. Several distinct pathways have been explored, leading identification most plausible sequence which both act synchronised manner.

Language: Английский

Potassium Hexamethyldisilazide (KHMDS): Solvent-Dependent Solution Structures DOI
Jesse A. Spivey, David B. Collum

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(26), P. 17827 - 17837

Published: June 20, 2024

Solution structures of potassium hexamethyldisilazide [KHMDS] and labeled [15N]KHMDS were examined using a number analytical methods including 29Si NMR spectroscopy density functional theory computations. A combination 15N–29Si couplings, chemical shifts, the method continuous variations reveals dimers, monomers, ion pairs. Weakly coordinating monofunctional ligands such as toluene, N,N-dimethylethylamine, Et3N afford exclusively dimers. 1,3-Dioxolane, THF, dimethoxyethane, hexamethylphosphoramide, diglyme provide dimers at low ligand concentrations monomers high concentrations. N,N,N′,N'-Tetramethylethylenediamine N,N,N′,N'-tetramethylcyclohexanediamine all ambient temperatures significant monomer −80 °C. Studies 12-crown-4 ran into technical problems. Equimolar 15-crown-5 forms dimer, whereas excess affords putative pair. Whereas equimolar 18-crown-6 also an provides rather than solvent-separated [2.2.2]cryptand what is believed to be contact-ion-paired cryptate. Solvation was probed largely (DFT) Thermally corrected energies are consistent with lower aggregates higher solvates temperatures, but magnitudes computed temperature dependencies substantially larger experimentally derived data.

Language: Английский

Citations

5
Mechanistic Insight into Alkali‐Metal Mediation of Styrene Transfer Hydrogenation: A DFT Study DOI Creative Commons
Keelan M. Byrne, Stuart D. Robertson, Robert E. Mulvey

et al.

ChemCatChem, Journal Year: 2024, Volume and Issue: unknown

Published: June 18, 2024

Abstract A computational mechanistic study was performed to investigate the transfer hydrogenation of styrene catalysed by a potassium tris‐hexamethyldisilazide magnesiate in presence 1,4‐cyclohexadiene. Exploiting cooperative effects between Mg and K centres present this tris(amide) complex results selective formation desired product ethylbenzene. The calculations demonstrate synergy metal within bimetallic complex, since neither monometallic amide K(HMDS) nor magnesium Mg(HMDS) 2 on their own can efficiently execute transformation under experimental conditions. Several distinct pathways have been explored, leading identification most plausible sequence which both act synchronised manner.

Language: Английский

Citations

0