The concept of diastereoselectivity switch in gold catalysis is investigated, which primarily depends on the effects of ligand and counterion. The origins of gold-catalyzed post-Ugi ipso-cyclization for the diastereoselective synthesis of spirocyclic pyrrol-2-one-dienone have been explored with density functional theory calculations. The reported mechanism emphasized the importance of the cooperation of ligand and counterion in diastereoselectivity switch, leading to the stereocontrolling transition states. Furthermore, the nonbonding interactions primarily between the catalyst and the substrate play a significant role in the cooperation of ligand and counterion. This work would be useful to further understand the reaction mechanism of gold-catalyzed cyclization and the effects of ligand and counterion.
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http://dx.doi.org/10.1021/acsomega.3c01279 | DOI Listing |
Acta Crystallogr E Crystallogr Commun
October 2024
Department of Chemistry, KU Leuven, Biomolecular Architecture, Celestijnenlaan 200F, Leuven (Heverlee), B-3001, Belgium.
Two new zinc(II) complexes, tri-ethyl-ammonium di-chlorido-[2-(4-nitro-phen-yl)-4-phenyl-quinolin-8-olato]zinc(II), (CHN){Zn(CHNO)Cl] (), and bis-(tri-ethyl-ammonium) {2,2'-[1,4-phenyl-enebis(nitrilo-methyl-idyne)]diphenolato}bis-[di-chlorido-zinc(II)], (CHN)[Zn(CHNO)Cl] (), were synthesized and their structures were determined using ESI-MS spectrometry, H NMR spectroscopy, and single-crystal X-ray diffraction. The results showed that the ligands 2-(4-nitro-phen-yl)-4-phenyl-quinolin-8-ol () and ,'-bis-(2-hy-droxy-benzyl-idene)benzene-1,4-di-amine () were deprotonated by tri-ethyl-amine, forming the counter-ion EtNH, which inter-acts an N-H⋯O hydrogen bond with the ligand. The Zn atoms have a distorted trigonal-pyramidal () and distorted tetra-hedral () geometries with a coord-ination number of four, coordinating with the ligands N and O atoms.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
October 2024
Department of Chemistry & Biochemistry California State Polytechnic University, Pomona 3801 W Temple Ave Pomona CA 91768 USA.
The crystal structure of the title compound, hexa-aqua-nickel(II) dichloride-1,4,7,10,13,16-hexa-oxa-cyclo-octa-deca-ne-water (1/2/2), [Ni(HO)]Cl·2CHO·2HO, is reported. The asymmetric unit contains half of the Ni(OH) moiety with a formula of CHClNiO at 105 K and triclinic (1) symmetry. The [Ni(OH)] cation has close to ideal octa-hedral geometry with O-Ni-O bond angles that are within 3° of idealized values.
View Article and Find Full Text PDFJ Chem Inf Model
December 2024
Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie Private, Ottawa K1N 6N5, Canada.
Efficient computational screenings are integral to materials discovery in highly sought-after gas adsorption and storage applications, such as CO capture. Preprocessing techniques have been developed to render experimental crystal structures suitable for molecular simulations by mimicking experimental activation protocols, particularly residual solvent removal. Current accounts examining these preprocessed materials databases indicate the presence of assorted structural errors introduced by solvent removal and preprocessing, including improper elimination of charge-balancing ions and ligands.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
December 2024
Laboratoire de Cristallographie-Themodynamique, Faculté de Chimie, USTHB, BP 32 El-Alia Bab Ezzouar, Algiers, 16111, Algeria.
Chem Sci
December 2024
CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT 205 Route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4 France +33-561553003 +33-561333174.
Catalytic asymmetric hydrogenation of ketones is an important approach to prepare valuable chiral alcohols. Understanding how transition metals promote these reactions is key to the rational design of more active, selective and sustainable catalysts. A highly unusual mechanism for asymmetric hydrogenation of acetophenone catalysed by an anionic Ir hydride system, including a strong counterion dependence on catalyst activity, is explored and rationalised here.
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