A rhodium-catalyzed method for the hydrogenation of -heteroarenes is described. A diverse array of unsubstituted -heteroarenes including pyridine, pyrrole, and pyrazine, traditionally challenging substrates for hydrogenation, were successfully hydrogenated using the organometallic precatalysts, [(η-CMe)Rh(N-C)H] (N-C = 2-phenylpyridinyl (ppy) or benzo[]quinolinyl (bq)). In addition, the hydrogenation of polyaromatic -heteroarenes exhibited uncommon chemoselectivity. Studies into catalyst activation revealed that photochemical or thermal activation of [(η-CMe)Rh(bq)H] induced C(sp)-H reductive elimination and generated the bimetallic complex, [(η-CMe)Rh(μ,η-bq)Rh(η-CMe)H]. In the presence of H, both of the [(η-CMe)Rh(N-C)H] precursors and [(η-CMe)Rh(μ,η-bq)Rh(η-CMe)H] converted to a pentametallic rhodium hydride cluster, [(η-CMe)RhH], the structure of which was established by NMR spectroscopy, X-ray diffraction, and neutron diffraction. Kinetic studies on pyridine hydrogenation were conducted with each of the isolated rhodium complexes to identify catalytically relevant species. The data are most consistent with hydrogenation catalysis prompted by an unobserved multimetallic cluster with formation of [(η-CMe)RhH] serving as a deactivation pathway.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jacs.9b09540 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Molecular Photoelectrocatalysis for Radical Reactions.
Acc Chem Res
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, and Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen 361005, P. R. China.
ConspectusMolecular photoelectrocatalysis, which combines the merits of photocatalysis and organic electrosynthesis, including their green attributes and capacity to offer novel reactivity and selectivity, represents an emerging field in organic chemistry that addresses the growing demands for environmental sustainability and synthetic efficiency. This synergistic approach permits access to a wider range of redox potentials, facilitates redox transformations under gentler electrode potentials, and decreases the use of external harsh redox reagents. Despite these potential advantages, this area did not receive significant attention until 2019, when we and others reported the first examples of modern molecular photoelectrocatalysis.
View Article and Find Full Text PDFRuthenium-Catalyzed Carbocycle-Selective Hydrogenation of Fused Heteroarenes.
J Am Chem Soc
December 2024
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
The homogeneous catalytic hydrogenation of benzo-fused heteroarenes generally provides partially hydrogenated products wherein the heteroaryl ring is preferentially reduced, such as quinoline hydrogenation, leading to 1,2,3,4-tetrahydroquinoline. Herein, we report a carbocycle-selective hydrogenation of fused -heteroarenes (quinoline, isoquinoline, quinoxaline, etc.) using the Ru complex of a chiral spiroketal-based diphosphine (SKP) as the catalyst, affording the corresponding 5,6,7,8-tetrahydro products in high chemoselectivities.
View Article and Find Full Text PDFCyclometalated -Difluoromethylbenzimidazolylidene Platinum(II) Complexes with Built-in Secondary Coordination Spheres: Photophysical Properties and Bioimaging.
Inorg Chem
December 2024
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, China.
Bidentate Pt(II) complexes with cyclometalated -heteroarene or -heterocyclic carbene (NHC) ligands have been extensively studied as phosphorescent emitters over the past two decades. Herein, we introduce a difluoromethyl group (CFH) into the wingtip of NHCs, where CFH acts as a lipophilic hydrogen bond (HB) donor. Their cyclometalated Pt(II) complexes show excellent PLQYs (up to 93%) and phosphorescence lifetimes mainly due to the rigid structure with hydrogen bonding between the CFH group and the adjacent O atom at the β-diketonate ligand.
View Article and Find Full Text PDFDual Ce@g-CN-Photoredox/Chlorine Catalysis: Cross-Dehydrogenative Coupling of -Heteroarenes and Alkanes/Ethers with H Evolution.
Org Lett
November 2024
School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
With Ce@g-CN as a heterogeneous semiconductor photocatalyst, BuNCl as both a redox catalyst and a hydrogen atom transfer catalyst, the first example of semiheterogeneous photocatalytic cross-dehydrogenative coupling of -heteroarenes and alkanes/ethers with H evolution was developed. Both a diverse array of high-value alkylated -heteroarenes and clean H can be efficiently coproduced under sacrificial reagent- and chemical oxidant/reductant-free conditions. Combining both the reversible Ce/Ce redox pair and the reversible Cl̅/Cl ̇ redox pair can considerably improve the photocatalytic efficiency.
View Article and Find Full Text PDFLate-Stage Halogenation of Complex Substrates with Readily Available Halogenating Reagents.
Acc Chem Res
November 2024
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Xue Yuan Road 38, Beijing 100191, China.
ConspectusLate-stage halogenation, targeting specific positions in complex substrates, has gained significant attention due to its potential for diversifying and functionalizing complex molecules such as natural products and pharmaceutical intermediates. Utilizing readily available halogenating reagents, such as hydrogen halides (HX), N-halosuccinimides (NXS), and dichloroethane (DCE) reagents for late-stage halogenation shows great promise for expanding the toolbox of synthetic chemists. However, the reactivity of haleniums (X, X = Cl, Br, I) can be significantly hindered by the presence of various functional groups such as hydroxyl, amine, amide, or carboxylic acid groups.
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!