Tuning metal–metal interactions for cooperative small molecule activation

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(23), P. 2839 - 2853

Published: Jan. 1, 2021

This Feature Article describes recent advances in the design of multinucleating ligands that support small molecule activation chemistry.

Language: Английский

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Cooperative approaches in catalytic hydrogenation and dehydrogenation

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(6), P. 1881 - 1898

Published: Jan. 1, 2022

This review uses catalytic hydrogenation and dehydrogenation processes as a platform to compare metal–ligand cooperativity metal–metal strategies in catalysis.

Language: Английский

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Small molecule activation with bimetallic systems: a landscape of cooperative reactivity

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(80), P. 11220 - 11235

Published: Jan. 1, 2022

This Feature Article highlights our group's efforts to investigate the structure, bonding, and reactivity of singly multiply bonded bimetallic complexes.

Language: Английский

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Electrocatalysis with Molecular Transition-Metal Complexes for Reductive Organic Synthesis

JACS Au, Journal Year: 2022, Volume and Issue: 2(6), P. 1266 - 1289

Published: May 31, 2022

Electrocatalysis enables the formation or cleavage of chemical bonds by a genuine use electrons holes from an electrical energy input. As such, electrocatalysis offers resource-economical alternative pathways that bypass sacrificial, waste-generating reagents often required in classical thermal redox reactions. In this Perspective, we showcase exploitation molecular electrocatalysts for electrosynthesis, particular reductive conversion organic substrates. Selected case studies illustrate efficient not only are appropriate shuttles but also embrace features organometallic catalysis to facilitate and control steps. From these examples, guidelines proposed design suited reduction We finally expose opportunities brought catalyzed electrosynthesis functionalize backbones, namely using sustainable building blocks.

Language: Английский

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Cooperative Bond Activation and Facile Intramolecular Aryl Transfer of Nickel–Aluminum Pincer‐type Complexes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(27), P. 15087 - 15094

Published: April 19, 2021

Abstract Pincer‐type nickel–aluminum complexes were synthesized using two equivalents of the phosphinoamide, [PhNCH 2 P i Pr ] − . The Ni 0 –Al III complexes, {( Mes PAlP)Ni} (μ‐N ) and (μ‐COD), where PAlP is (Mes)Al(NPhCH , structurally characterized. (PAlP)Ni system exhibited cooperative bond cleavage mediated by two‐site Ni–Al unit, including oxidative addition aryl halides, H activation, ortho‐directed C−H activation pyridine N‐oxide. One intriguing reaction reversible intramolecular transfer mesityl ring from Al to site, which evocative transmetalation step during cross‐coupling catalysis. aryl‐transfer product,(THF)Al(NPhCH Ni(Mes), first example a first‐row transition metal–aluminyl pincer complex. judicious donor enables metalloligand convert reversibly between alane aluminyl forms via group Ni, respectively. Theoretical calculations support zwitterionic δ− δ+ electronic structure in nickel–aluminyl

Language: Английский

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Cobalt-Catalyzed Hydrosilylation of Carbon Dioxide to the Formic Acid, Formaldehyde, and Methanol Level─How to Control the Catalytic Network?

JACS Au, Journal Year: 2021, Volume and Issue: 1(11), P. 2058 - 2069

Published: Oct. 4, 2021

The selective hydrosilylation of carbon dioxide (CO2) to either the formic acid, formaldehyde, or methanol level using a molecular cobalt(II) triazine complex can be controlled based on reaction parameters such as temperature, CO2 pressure, and concentration. Here, we rationalize catalytic mechanism that enables arrival at each product platform. Key reactive intermediates were prepared spectroscopically characterized, while energy profile analyzed with density functional theory (DFT) methods microkinetic modeling. It transpired stepwise reduction involves three consecutive cycles, including same cobalt(I) hydride active species. increasing kinetic barriers associated step competing transfer steps in cycles corroborate strong influence catalyst environment selectivity. fundamental mechanistic insights provide consistent description system rationalize, particular, experimentally verified opportunity steer toward formaldehyde chemically most challenging level.

Language: Английский

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Cooperative C–H Bond Activation by a Low-Spin d⁶ Iron–Aluminum Complex

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(19), P. 8770 - 8777

Published: May 5, 2022

The reactions of transition metal complexes underpin numerous synthetic processes and catalytic transformations. Typically, this reactivity involves the participation empty filled molecular orbitals centered on metal. Kinetically stabilized species, such as octahedral low-spin d6 complexes, are not expected to participate directly in these reactions. However, novel approaches that exploit metal–ligand cooperativity offer an opportunity challenge preconceptions. Here, we show inclusion aluminum-based ligand into coordination sphere neutral iron complex leads unexpected reactivity. Complexes featuring unsupported Fe–Al bond capable intermolecular C–H activation pyridines. Mechanistic analysis suggests proceeds through a reductive deprotonation which two centers (Fe Al) act like frustrated Lewis pair. key behavior is ground state destabilization complex, brought about by electropositive ligand. These findings have immediate implications for design reagents catalysts based first-row metals.

Language: Английский

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The Rise of Manganese-Catalyzed Reduction Reactions

Synthesis, Journal Year: 2021, Volume and Issue: 54(03), P. 517 - 534

Published: Sept. 29, 2021

Abstract Recent developments in manganese-catalyzed reducing transformations—hydrosilylation, hydroboration, hydrogenation, and transfer hydrogenation—are reviewed herein. Over the past half a decade (i.e., 2016 to present), more than 115 research publications have been reported these fields. Novel organometallic compounds new reduction transformations discovered further developed. Significant challenges that had historically acted as barriers for use of manganese catalysts reactions are slowly being broken down. This review will hopefully assist developing this area, by presenting clear concise overview catalyst structures substrate published so far. 1 Introduction 2 Hydrosilylation 3 Hydroboration 4 Hydrogenation 5 Transfer 6 Conclusion Perspective

Language: Английский

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Alcohol-Assisted Hydrogenation of Carbon Monoxide to Methanol Using Molecular Manganese Catalysts

JACS Au, Journal Year: 2021, Volume and Issue: 1(2), P. 130 - 136

Published: Jan. 25, 2021

Alcohol-assisted hydrogenation of carbon monoxide (CO) to methanol was achieved using homogeneous molecular complexes. The manganese complex [Mn(CO)2Br[HN(C2H4P i Pr2)2]] ([HN(C2H4P Pr2)2] = MACHO- Pr) revealed the best performance, reaching up turnover number 4023 and frequency 857 h-1 in EtOH/toluene as solvent under optimized conditions (T 150 °C, p(CO/H2) 5/50 bar, t 8-12 h). Control experiments affirmed that reaction proceeds via formate ester intermediate, whereby a catalytic amount base found be sufficient mediate its formation from CO alcohol situ. Selectivity for reached >99% with no accumulation ester. demonstrated work component, resulting reactive system allows "breeding" without any coreagents.

Language: Английский

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A Proton‐Responsive Pyridyl(benzamide)‐Functionalized NHC Ligand on Ir Complex for Alkylation of Ketones and Secondary Alcohols

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 27(41), P. 10737 - 10748

Published: May 17, 2021

Abstract A Cp*Ir(III) complex ( 1 ) of a newly designed ligand L featuring proton‐responsive pyridyl(benzamide) appended on N ‐ heterocyclic carbene (NHC) has been synthesized. The molecular structure reveals dearomatized form the ligand. protonation with HBF 4 in tetrahydrofuran gives corresponding aromatized [Cp*Ir(L H)Cl]BF 2 ). Both compounds are characterized spectroscopically and by X‐ray crystallography. acid is examined H NMR UV‐vis spectra. character exploited for catalyzing α ‐alkylation ketones β secondary alcohols using primary as alkylating agents through hydrogen‐borrowing methodology. Compound an effective catalyst these reactions exhibits superior activity comparison to structurally similar iridium )Cl]PF 6 3 lacking pendant amide moiety. catalytic alkylation wide substrate scope, low base loadings, short reaction time. efficacy also demonstrated syntheses quinoline lactone derivatives via acceptorless dehydrogenation, selective two steroids, pregnenolone testosterone. Detailed mechanistic investigations DFT calculations substantiate role process.

Language: Английский

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