Frustrated Radical Pairs: From Fleeting Intermediates to Isolable Species DOI Creative Commons
Lars J. C. van der Zee, J. Hofman, Simon Mathew

et al.

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 8, 2024

Abstract We present the design and comprehensive investigation of stable para ‐substituted triarylamine–2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) radical ion pairs (RIPs) generated via single‐electron transfer (SET). quantified degree SET in both solution solid phases, utilising a suite spectroscopic techniques including IR, EPR, NMR, single‐crystal X‐ray diffraction (SC–XRD). Our findings reveal that extent is significantly influenced by nature substituents (MeO > t Bu Br) polarity solvent (MeCN DCM toluene). The pair [( p MeOPh) 3 N]⋅ + [DDQ]⋅ − was unambiguously identified using EPR UV–vis spectroscopy, its structure confirmed SC–XRD. Detailed analysis indicates an open‐shell singlet ground state with thermally accessible triplet state, as corroborated magnetic susceptibility measurements, DFT calculations. This study offers crucial insights into mechanistic pathways RIP formation tuning states, laying groundwork for future exploration their reactivity potential applications.

Language: Английский

Synthesis of Graphene Nanosheets from Coconut and Candlenut Shells: Large-Scale Production and Application in Fe Ion Adsorption and Electrochemical Properties DOI Creative Commons
Yosia Gopas Oetama Manik, Boon Tong Goh, Rikson Siburian

et al.

ACS Omega, Journal Year: 2025, Volume and Issue: 10(4), P. 3338 - 3350

Published: Jan. 17, 2025

Graphene nanosheets (GNS) have garnered significant attention due to their exceptional properties and wide-ranging applications. This research aims synthesize GNS from coconut shells candlenut compare performance in Fe ion adsorption electrochemical properties. Both were used as raw materials, the pyrolysis method was chosen produce large-scale GNS. The characterized using Raman spectroscopy, X-ray diffraction, FTIR, FESEM-EDX, AAS, measurements, including CV EIS on modified electrodes. New findings this study reveal that derived exhibit thinner layers fewer defects compared with those shells. structural advantage contributes superior efficiency better performance, making more suitable for applications flexible electronics devices. Furthermore, synthesis effectively reduces amount of oxides associated GNS, enhancing material's potential high-performance produced showed an effectiveness 0.33 ± 0.012 mg/g, a charge transfer resistance 0.78 kΩ, capacitance 108.8 F/g, indicating promising role future technological

Language: Английский

Citations

1
Covalent Organic Framework-Derived B/N Co-Doped Carbon FLPs Metal-Free Catalysts for the Selective Hydrogenation of α,β-Unsaturated Aldehydes to Unsaturated Alcohols DOI
Linhao Zhong,

Xiaoqing Liao,

Haishuai Cui

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(20), P. 15799 - 15810

Published: Oct. 10, 2024

An ongoing challenge is to precisely tailor the frustrated Lewis pairs (FLPs) sites construct all-solid-state FLPs metal-free catalysts that are as effective or even more than homogeneous/metal in H2 activation. In this study, B/N codoped carbon (SNW-BCN) were prepared by tailoring targeted doping of B atoms nitrogen-rich covalent organic framework (SNW-1) using ligand-exchange strategy and self-templated carbonization. The then applied selective hydrogenation α,β-unsaturated aldehydes unsaturated alcohols. It was found a significant amount pyridinic-N could be obtained from SNW-1. Moreover, can accomplished introducing ligands (4-formylphenylboronic acid) with acid heteroatoms pre-empt ligand site Additionally, B–N bond, which preferentially forms between neighboring N at high temperature, function site. DFT calculations situ characterizations show electron-rich electron-deficient form B–N/pyridinic-N sites, effectively activate C═O aldehydes, only 0.36 eV H–H bond dissociation energy. This work encourages environmentally friendly synthesis alcohols offers fresh concepts for development catalysts. experiments on catalyst scale-up also investigated because they might shed light production large scale.

Language: Английский

Citations

4
Structural Snapshots of Reversible Carbon Dioxide Capture and (De)oxygenation at Group 14 Diradicaloids DOI
Falk Ebeler,

Beate Neumann,

Hans‐Georg Stammler

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 8, 2024

Although diradicals should exhibit a rather small reaction barrier as compared to closed-shell species for activating kinetically inert molecules, the activation and functionalization of carbon dioxide with stable main-group remain virtually unexplored. In this work, we present thorough study on CO2 activation, reversible capture, (de)oxygenation mediated by Group 14 singlet (i.e., diradicaloids) [(ADC)E]2 (E = Si, Ge, Sn) based an anionic dicarbene (ADC) framework (ADC PhC{N(Dipp)C}2; Dipp 2,6-iPr2C6H3). readily undergo [4 + 2]-cycloadditions result in barrelene-type bis-metallylenes [(ADC)E]2(OC═O). The addition is E Ge; thus, detaches under vacuum or at elevated temperature regenerates [(ADC)Ge]2. [(ADC)Sn]2(OC═O) isolable but deoxygenates additional form [(ADC)Sn]2(O2CO) CO. [(ADC)Si]2(OC═O) extremely reactive could not be isolated detected it spontaneously reacts further yield elusive monomeric Si(IV) oxides [(ADC)Si(O)]2(COn) carbonates [(ADC)Si(CO3)]2(COn) (n 1 2) via CO2. molecular structures all compounds have been established X-ray diffraction, mechanistic insight their formation has suggested DFT calculations.

Language: Английский

Citations

3
On the role of thermally activated EDA complexes in decarboxylative cross-coupling DOI

Nathan Dao,

Ryan A. Shenvi

Tetrahedron, Journal Year: 2024, Volume and Issue: 166, P. 134204 - 134204

Published: Aug. 17, 2024

Language: Английский

Citations

0
Frustrated Radical Pairs: From Fleeting Intermediates to Isolable Species DOI Creative Commons
Lars J. C. van der Zee, J. Hofman, Simon Mathew

et al.

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 8, 2024

Abstract We present the design and comprehensive investigation of stable para ‐substituted triarylamine–2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) radical ion pairs (RIPs) generated via single‐electron transfer (SET). quantified degree SET in both solution solid phases, utilising a suite spectroscopic techniques including IR, EPR, NMR, single‐crystal X‐ray diffraction (SC–XRD). Our findings reveal that extent is significantly influenced by nature substituents (MeO > t Bu Br) polarity solvent (MeCN DCM toluene). The pair [( p MeOPh) 3 N]⋅ + [DDQ]⋅ − was unambiguously identified using EPR UV–vis spectroscopy, its structure confirmed SC–XRD. Detailed analysis indicates an open‐shell singlet ground state with thermally accessible triplet state, as corroborated magnetic susceptibility measurements, DFT calculations. This study offers crucial insights into mechanistic pathways RIP formation tuning states, laying groundwork for future exploration their reactivity potential applications.

Language: Английский

Citations

0