Carbon neutral hydrogen storage and release cycles based on dual-functional roles of formamides

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: June 22, 2023

The development of alternative clean energy carriers is a key challenge for our society. Carbon-based hydrogen storage materials are well-suited to undergo reversible (de)hydrogenation reactions and the catalysts individual process steps crucial. In current state, noble metal-based still dominate this field. Here, system partially carbon-neutral release reported. It based on dual-functional roles formamides uses small molecule Fe-pincer complex as catalyst, showing good stability reusability with high productivity. Starting from formamides, quantitative production CO-free achieved at selectivity ( > 99.9%). This works modest temperatures 90 °C, which can be easily supplied by waste heat e.g., proton-exchange membrane fuel cells. Employing such system, we achieve >70% H2 evolution efficiency >99% in 10 charge-discharge cycles, avoiding undesired carbon emission between cycles.

Language: Английский

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Reactivity umpolung (reversal) of ligands in transition metal complexes

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(6), P. 2808 - 2827

Published: Jan. 1, 2024

The power of transition metal ions and their ligands to reverse the native reactivity small molecules is highlighted by providing examples for 15 classes including types L, XL, X, X 2 , 3 .

Language: Английский

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Broadly Applicable Copper(I)-Catalyzed Alkyne Semihydrogenation and Hydrogenation of α,β-Unsaturated Amides Enabled by Bifunctional Iminopyridine Ligands

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: April 16, 2025

A highly active bifunctional catalyst consisting of a copper(I)/N-heterocyclic carbene complex and basic 2-iminopyridine subunit allows for copper hydride chemistry under low H2 pressure, achieving efficient catalysis reaching 1 bar (balloon pressure). The tolerates remarkable variety functional groups in catalytic alkyne semihydrogenations. Furthermore, this design gives rise to high reactivity that the hydrogenation α,β-unsaturated amides (a substrate class hitherto unreactive catalysis) at pressure first time. In manner, late-stage modification isotope labeling amides, common subunits biologically compounds, can be realized through using first-row transition metal based on abundant copper. Preliminary mechanistic experiments indicate operates via an iminopyridine-mediated proximity effect. We hypothesize coordination alcohol as proton source copper(I) facilitates overall reactions rapid proto-decupration step.

Language: Английский

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Balancing the Seesaw in Mn-Catalyzed N-Heteroarene Hydrogenation: Mechanism-Inspired Catalyst Design for Simultaneous Taming of Activation and Transfer of H₂

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(7), P. 4824 - 4834

Published: March 27, 2023

Recently, Mn-catalyzed hydrogenation reactions have gained significant interest due to their importance in various challenging transformations. Among several classes of organic substrates, including amides, ketones, carbamates, urea-derivatives, (cyclic) carbonates/polycarbonates, CO2, and CO2 derivatives, N-heteroarene using a Mn-based system is severely underdeveloped. Only handful reports are known the literature, which mainly use expensive phosphine-based ligand systems for designing effective Mn catalysts. Mechanistically, pincer catalysts, H2-activation step was facilitated by typical metal–ligand bifunctional mechanism through so-called "Mn-amino"/"Mn-amido" platform, while H2-transfer (in form hydride proton transfer) triggered judiciously designed stereoelectronically tuned P- and/or N-donor ligands attached at center. Interestingly, these two steps, i.e., H2-transfer, often counteract owing opposite stereoelectronic demands metal center, existing PNP-Mn NNP-Mn catalysts indeed suffer from disbalanced energetics case steps. With rationally analyzed approach, herein, we show how crucial steps can be simultaneously tamed balanced optimize kinetic thermodynamic demand. Thus, exchange both P N arms PNP/NNP framework with better σ-donor, moderate π-acceptor, sterically nonhindering planar such as N-heterocyclic carbenes (NHCs), keeping central amino/amido-based H2-activating motif intact, critical catalytic cycle reducing corresponding activation barriers balancing stability Mn-hydride species (ΔG# H2-cleavage: 19.2 kcal/mol; ΔG# H2 (hydride/proton)-transfer: 22.2 ΔG H2-cleavage step: −2.8 kcal/mol). Eventually, bis-NHC-armed CNC-Mn catalyst, mechanism-inspired proved apt efficient variety N-heteroarenes, under 10–60 bar pressure 60–120 °C temperature within 6–12 h reaction time.

Language: Английский

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Base-Free Reversible Hydrogen Storage Using a Tethered π-Coordinated-Phenoxy Ruthenium-Dimer Precatalyst

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(9), P. 5787 - 5794

Published: April 13, 2023

A dimeric tethered π-coordinated-phenoxy ruthenium precatalyst has been used for the base-free hydrogenation of CO2 in DMSO. The same was also efficient reverse dehydrogenation formic acid yet under conditions. An unprecedented cycle consisting hydrogen storage and release successfully implemented with precatalyst. latent property catalyst introduced concept storage/transportation/release.

Language: Английский

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NNN manganese complex-catalyzed α-alkylation of methyl ketones using alcohols: an experimental and computational study

Dalton Transactions, Journal Year: 2024, Volume and Issue: 53(7), P. 3236 - 3243

Published: Jan. 1, 2024

A quinoline-based pincer Mn catalyst for α-alkylation of methyl ketones using primary alcohols as alkyl surrogates is presented. The C–C bond formation reaction proceeds via a hydrogen auto-transfer protocol, generating water the only by-product.

Language: Английский

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Highly efficient hydrogenation of carbamates catalyzed by pincer ruthenium complexes

Journal of Catalysis, Journal Year: 2023, Volume and Issue: 428, P. 115165 - 115165

Published: Oct. 14, 2023

Language: Английский

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Ethanol as hydrogen donor: An efficient transfer hydrogenation of aldehydes, ketones, and nitroarenes with H-bonded Ru(II)-N-heterocyclic iminium complex

Journal of Catalysis, Journal Year: 2023, Volume and Issue: 429, P. 115207 - 115207

Published: Nov. 20, 2023

Language: Английский

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Utilising a Proton‐Responsive 1,8‐Naphthyridine Ligand for the Synthesis of Bimetallic Palladium and Platinum Complexes

Chemistry - An Asian Journal, Journal Year: 2024, Volume and Issue: 19(3)

Published: Jan. 1, 2024

Abstract We present four proton‐responsive palladium and platinum complexes, [MCl 2 ( R PONNHO)] (M=Pd, Pt; R= i Pr, t Bu) synthesised by complexation of PdCl or PtCl (COD) with the 1,8‐naphthyridine ligand PONNHO. Deprotonation tBu switches coordination from mono‐ to dinucleating, offering a synthetic pathway bimetallic Pd II Pt complexes [M Cl PONNO) ]. Two‐electron reduction gives planar M I −M ] Pt) containing metal‐metal bond. In contrast related nickel system that forms metallophosphorane [Ni PONNOPONNO)], an unusual phosphinite binding mode is observed in close phosphinite‐naphthyridinone P⋅⋅⋅O interactions, which investigated spectroscopically, crystallographically computationally. The presented structurally‐responsive PONNHO PONNO offer novel platform for future explorations metal‐ligand cooperativity platinum.

Language: Английский

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Nanoscale Ni–NiO–ZnO Heterojunctions for Switchable Dehydrogenation and Hydrogenation through Modulation of Active Sites

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(20), P. 24329 - 24345

Published: May 15, 2023

Catalysts consisting of metal-metal hydroxide/oxide interfaces are highly in demand for advanced catalytic applications as their multicomponent active sites will enable different reactions to occur close proximity through synergistic cooperation when a single component fails promote it. To address this, herein we disclosed simple, scalable, and affordable method synthesizing catalysts nanoscale nickel-nickel oxide-zinc oxide (Ni-NiO-ZnO) heterojunctions by combination complexation pyrolytic reduction. The modulation was achieved varying the reaction conditions pyrolysis, controlling growth, inhibiting interlayer interaction Ostwald ripening efficient use coordinated acetate amide moieties Zn-Ni materials (ZN-O), produced between hydrazine hydrate Zn-Ni-acetate complexes. We found that organic crucial forming superior activity. analyzed two antagonistic evaluate performance while heterostructure Ni-NiO-ZnO cooperative synergy were managing effectiveness selectivity catalyst dehydrogenation aryl alkanes/alkenes, they failed enhance hydrogenation nitro arenes. influenced shape, surface properties, hydroxide both zinc nickel, particularly accessible Ni(0). showed functional group tolerance, multiple reusabilities, broad substrate applicability, good activity reactions.

Language: Английский

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