Article
Chemistry, Multidisciplinary
Tingting Li, Gerald B. Hammond, Bo Xu
Summary: A widely applicable approach to synthesize ketones, esters, and amides via the oxidative C-C bond cleavage of readily available alkyl aldehydes has been developed using green and abundant molecular oxygen as the oxidant, and base metals (cobalt and copper) as catalysts. This strategy can be extended to the one-pot synthesis of ketones from primary alcohols and alpha-ketoamides from aldehydes.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Xiaotong Xu, Shuqi Dai, Shuai Xu, Qi Zhu, Yuliang Li
Summary: In this study, a polymeric carbon nitride/polyhedral oligomeric silsesquioxane PDI heterojunction photocatalyst was prepared to overcome the charge localization effect and strong intermolecular aggregation in PDI, leading to improved cleavage conversion efficiency and promising application prospects.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Xinnan Lu, Roxanne Clement, Yong Lu, Belen Albela, R. Tom Baker, Laurent Bonneviot
Summary: The development of selective and robust heterogeneous oxidation catalysts is crucial for converting biomass-derived platform chemicals. A microwave-assisted synthesis method was used to incorporate vanadium active sites into mesoporous silica, while Al/Ti/Zr/Ce anchoring ions were introduced to minimize vanadium leaching and improve substrate conversion selectivity. The catalysts showed 2D VOx layers stabilized on anchors, with Ti-IV ions proving to be the best for preventing V leaching and Al-III/Zr-IV ions for enhancing substrate conversion selectivity, in the presence of weakly polar solvents like toluene and ethyl acetate as suitable reaction solvents. The high selectivity for C-C bond cleavage suggests a heterogeneous catalytic pathway different from previously reported molecular oxovanadium (V) catalysts.
Article
Engineering, Environmental
Shibo Shao, Ke Wang, Jason B. Love, Jialin Yu, Shangfeng Du, Zongyang Yue, Xianfeng Fan
Summary: A sulfur-rich zinc indium sulfide photocatalyst was developed to promote the cleavage of C-beta-O linkages in lignin, using water as a hydrogen donor. The reaction selectivity for aromatic monomers increased and the conversion rate of lignin model compounds improved significantly. This study provides a new and effective strategy to promote the cleavage of C-beta-O linkages and is helpful for the future development of photocatalytic lignin valorization.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Hua Zhou, Zhenhua Li, Si-Min Xu, Lilin Lu, Ming Xu, Kaiyue Ji, Ruixiang Ge, Yifan Yan, Lina Ma, Xianggui Kong, Lirong Zheng, Haohong Duan
Summary: The study presents an efficient electrochemical strategy for upgrading lignin derivatives to carboxylates using MnCoOOH catalyst, with yields of 80-99% and operational stability up to 200 hours. A tandem oxidation mechanism is revealed, allowing for effective transformation of lignin derivatives into carboxylates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Tao Yi, Quan Liu, Yue Zhang, Jinhao Huang, Zhigang Zeng, Yunfeng Chen
Summary: A copper-catalyzed cascade reaction was reported for the selective oxidative cleavage of C-C bonds in β-alkyl nitroolefins, followed by oxidative amidation with amines or amides. The reaction showed high selectivity and yielded α-ketoamides with 66-88% yields. Mechanistic studies revealed that the reaction occurred on more electron-rich allylic nitro tautomers originating from the equilibrium of conjugated nitroalkenes.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Engineering, Environmental
Nan Shi, Yuanyuan Ding, Na Li, Fushan Wen, Dong Liu
Summary: Selective cleavage of C-C bond of lignin derivatives and models via oxidation is achieved using P2W17V/{001}-TiO2 heterogenous photocatalysts. The photocatalysts effectively transform lignin model compound to benzaldehyde and phenol, with a selectivity above 85%. This study provides a new approach to selectively break C-C bond in lignin under mild conditions.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Ying Chen, Chao Chen, Yonghong Liu, Lei Yu
Summary: Catalyzed by cerium ammonium nitrate (CAN), the oxidative cracking reaction of alkenes occurred to produce carbonyls in good yields under mild conditions. The reaction employed molecular oxygen (O2) as the safe and clean oxidant. The catalyst dosage was reduced to as low as 0.5 mol%, while no additive was required. Thus, it may afford a generally green synthetic approach for introducing oxygen into organic molecules as well as the biomass degradation and the resource recycling from the C=C bond-containing waste polymers. X-ray photoelectron spectroscopy (XPS) analysis and control experiments demonstrated that the process proceeded via a single electron transfer (SET) reaction-initiated free radical reaction mechanism. In the process, both Ce and NO3- acted as the oxygen carrier to promote the oxidation reaction. The application of the abundantly existed nitrate in CAN was found to be the key for reducing the catalyst loading.
CHINESE CHEMICAL LETTERS
(2023)
Article
Chemistry, Physical
Yuting Liu, Huifang Liu, Ning Li, Feng Wang
Summary: This study reports a novel photocatalytic strategy for the oxidative C-C cleavage of lignin and β-O-4 derivatives using photoredox organocatalysts. High yields of aromatic aldehydes and phenyl formate were obtained, and mixed binary organic solvents were shown to promote bond cleavage and inhibit over-oxidation side reactions. The absorbance, excitation, and interaction with the lignin model of the photocatalyst in different solvents were investigated, and a C-centered radical intermediate was captured, providing evidence for the direct Cα-Cβ bond cleavage mechanism.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Applied
Jintao Wu, Zehui Peng, Tong Shen, Zhong-Quan Liu
Summary: In this study, a new method for the oxidative cleavage of C(2)=C(3)/C(2)-N bonds of indoles using electrochemistry as the driving force is reported. Compared to previous strategies, this method avoids the use of heavy metals or stoichiometric chemical oxidants, and features metal-free conditions, air as the oxidant, and easy scalability.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Qingqing Zhang, Yi-Chun Chu, Zhulan Liu, Mei Hong, Weiwei Fang, Xin-Ping Wu, Xue-Qing Gong, Zupeng Chen
Summary: Photocatalytic lignin depolymerization is a sustainable and cost-competitive method to produce aromatic chemicals from renewable resources. In this study, a photocatalytic strategy utilizing triazine-heptazine-based carbon nitride heterojunctions was developed to achieve high-yield aromatic monomers by promoting C-C bond cleavage in lignin models. The improved photocatalytic performance was attributed to the accelerated charge carriers separation and migration induced by the built-in electric field at the heterojunction interface, and the facilitated C & beta;-radical generation.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Physical
Yang Sik Yun, Claudia E. Berdugo-Diaz, David W. Flaherty
Summary: Biomass has received considerable attention as an alternative to petrochemicals in the production of valuable chemicals and fuels. This Perspective discusses significant advancements in understanding the reaction networks and mechanisms, reactive intermediates, and active site motifs for selective production of desired compounds through hydrogenolysis over heterogeneous catalysts. Continuing research into hydrogenolysis reactions faces current challenges and provides opportunities for future exploration.
Article
Chemistry, Applied
Baoyu Wang, Peng Zhou, Ximing Yan, Hu Li, Hongguo Wu, Zehui Zhang
Summary: In this study, a dual-size MOF-derived Co catalyst was prepared for the conversion of lignin-derived o-methoxyphenols to cyclohexanols. The dual-size Co catalyst exhibited a cooperative effect in the selective demethoxylation process. The catalyst showed high recyclability and the cooperative catalytic strategy opens new avenues for biomass upgrading.
JOURNAL OF ENERGY CHEMISTRY
(2023)
Review
Chemistry, Physical
Christophe Coutanceau, Neha Neha, Thibault Rafaideen
Summary: Lignocellulosic biomass is a valuable carbon reservoir for the production of biofuels and chemicals. However, the low solubility and accessibility of the raw biopolymers hinder efficient conversion into useful compounds. Exploring alternative bio-sourced media and developing selective catalytic materials are important challenges for future biorefinery processes.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Nanoscience & Nanotechnology
Walace D. do Pim, Fernanda G. Mendonca, Gabriel Brunet, Glenn A. Facey, Floris Chevallier, Christophe Bucher, R. Tom Baker, Muralee Murugesu
Summary: The research systematically studied the modulation of catalytic performance of a cationic framework, finding that the catalytic activity is highly anion-dependent and significantly increases when different anionic species are incorporated. The incorporation of viologen moieties within the linker tunes the electrophilicity of the active copper(II) sites, resulting in stronger interactions with the substrate and enhanced catalytic performance.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Alexandra Rochon, Matthew R. Elsby, R. Tom Baker
Summary: The reactivity of Ni=CF2(dppe)[P(OMe)(3)] (1) with various fluorinated alkenes was investigated, leading to the formation of different metallacycles. Reacting 1 with perfluoro(methyl vinyl ether) and chlorotrifluoroethylene (CTFE) results in regiospecific formation of metallacyclobutanes, while reactions with trifluoroethylene (TrFE) and hexafluoropropene produce different unexpected products.
CANADIAN JOURNAL OF CHEMISTRY
(2021)
Article
Nanoscience & Nanotechnology
Walace D. do Pim, Fernanda G. Mendonca, Gabriel Brunet, Glenn A. Facey, Floris Chevallier, Christophe Bucher, R. Tom Baker, Muralee Murugesu
Summary: The research systematically studied the modulation of catalytic performance of a cationic framework, finding that the catalytic activity is highly anion-dependent and significantly increases when different anionic species are incorporated. The incorporation of viologen moieties within the linker tunes the electrophilicity of the active copper(II) sites, resulting in stronger interactions with the substrate and enhanced catalytic performance.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Inorganic & Nuclear
Yahya M. Albkuri, Jeffrey S. Ovens, Jessica Martin, R. Tom Baker
Summary: Nickel coordination chemistry with a biomimetic thiolate-imine-thioether SNSMe ligand exhibits diverse reactivity and multidentate ligand dynamics. Reactions of the ligands with nickel at different temperatures result in the formation of complexes with varying magnetic properties.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Matthew R. Elsby, Mina Son, Changjin Oh, Jessica Martin, Mu-Hyun Baik, R. Tom Baker
Summary: The study describes the chemoselective hydroboration of carbonyls using the paramagnetic bis-amido Mn[(SNSMe)-N-Me](2) complex (1). It was found that the bifunctional amido bis(thioether) ligand L plays a crucial role in the success of the reaction, while also ruling out the possibility of side reactions.
Article
Chemistry, Inorganic & Nuclear
Saeed Ataie, R. Tom Baker
Summary: Anionic ligands with multiple lone pairs of electrons cooperate with a metal center to achieve redox-neutral B-H bond activation. A series of NiIIX(NNN) complexes were synthesized, and it was found that the phenoxy derivative showed the highest activity, indicating that B-H bond activation occurs at the Ni-X bond. Stoichiometric reactions revealed that substrate insertion into the Ni-H bond is the first step in the catalytic cycle.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Alexandre J. Sicard, Behnaz Ghaffari, Bulat M. Gabidullin, Jeffrey S. Ovens, Russell P. Hughes, R. Tom Baker
Summary: In this study, bulky metal catalysts were used to react with vinylidene difluoride, resulting in the synthesis of a new type of HFO compound, with the reaction mechanism identified through calculations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Review
Chemistry, Multidisciplinary
Matthew R. Elsby, R. Tom Baker
Summary: Homogeneous catalysis plays a crucial role in the synthesis of fine chemicals and achieving carbon-neutrality. The development of first-row transition metal catalysts with simple and economical ligands composed of biomimetic donors is essential for sustainable catalysis. Metal-ligand cooperativity is an effective strategy to yield high-performing first-row metal molecular catalysts.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Luana L. T. N. Porto, Moutasem Seifi, Nicole Johnson, R. Tom Baker
Summary: Given the importance of fluorinated drugs and agrochemicals, researchers have been focusing on fluoroalkylation methods that can be performed at a late stage of chemical synthesis. One such method involves the insertion of fluoroalkenes into Cu-H bonds to obtain new fluoroalkyl groups. However, attempts to transfer -RF groups to aryl iodides result in aryl-aryl coupling products instead.
CANADIAN JOURNAL OF CHEMISTRY
(2023)
Article
Engineering, Chemical
Raheleh Zafari, Fernanda G. Mendonca, R. Tom Baker, Clemence Fauteux-Lefebvre
Summary: Adsorbents made from amine-functionalized cellulose were studied for SO2 capture, showing a significantly higher adsorption capacity compared to pristine nanocrystalline cellulose. The effects of functionalization time, temperature, and amount of amine were assessed, and the adsorption mechanism for SO2 capture was confirmed. The study also investigated the impact of different operating adsorption temperatures and flow rates on the capture capacity and breakthrough time of SO2.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Saeed Ataie, Maxwell Lohoar, Loic P. Mangin, R. Tom Baker
Summary: Three new IPr-Ag- and -Au-SNS amido and thiolate complexes were synthesized and compared to their previously reported Cu analogues as carbonyl hydroboration catalysts. Although these complexes showed no catalytic activity, treatment of the IPr-Ag-SNS amido complex with pinacolborane released N-borylated ligand, (SNSMe)-N-Me-S-Bpin, (L-1-Bpin). This finding led to reinvestigation of the IPr-Cu-SNS amido precatalyst, revealing immediate conversion of the catalyst system to [CuH(IPr)](2) upon loss of L-1-Bpin.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Matthew R. Elsby, Changjin Oh, Mina Son, Scott Y. H. Kim, Mu-Hyun Baik, R. Tom Baker
Summary: The role of S-donors in ligand-assisted catalysis using first-row metals has been investigated through experimental and computational mechanistic studies. The Mn(I) complex, Mn(kappa(3)-(SNS)-N-Me)(CO)(3), featuring thioether, imine, and thiolate donors, was found to require UV light for catalytic activity and showed evidence of CO ligand loss. Stoichiometric reactions revealed that the absence of nitriles led to the reduction of imine N=C in the ligand backbone, forming an inactive by-product. DFT calculations demonstrated the importance of the bifunctional thiolate donor, coordinative flexibility of the (SNS)-N-Me ligand, and access to an open-shell intermediate in achieving low-energy intermediates during catalysis.
Article
Chemistry, Multidisciplinary
Saeed Ataie, Jeffrey S. Ovens, R. Tom Baker
Summary: In this study, a new catalyst for esterification reaction was discovered, and the reaction mechanism was explored. The catalyst demonstrated high efficiency in converting nitrites to double hydroborated products.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Saeed Ataie, Seth Hogeterp, Jeffrey S. Ovens, R. Tom Baker
Summary: In this study, zinc complexes with different ligands were prepared and compared for their catalytic activity in carbonyl hydroboration. Mechanistic studies revealed two pathways for precatalyst activation, leading to an active zinc alkoxide catalyst. This work contributes to a better understanding of metal-ligand cooperation in first-row metal catalysis.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Matthew R. Elsby, Scott Y. H. Kim, Stephan N. Steinmann, R. Tom Baker
Summary: The bifunctional reactivity of three metal SNS (bis)amido complexes was computationally assessed by comparing the nucleophilicity of the M-N-amido donor (Mn, Fe, Co). Hirshfeld charges identified the Mn-N-amido donor as most nucleophilic and Fe as most electrophilic metal. The reaction energy profiles of a model bifunctional H-2 activation showed that Mn had the lowest reaction barrier, followed by Fe and Co.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Charles-Oneil L. Crites, Fernanda Gomes de Mendonca, Jose Carlos Netto-Ferreira, R. Tom Baker, Geniece L. Hallett-Tapley, Luc Tremblay
Summary: A new photocatalytic methodology was developed for the depolymerization of oxidized Kraft lignin to industrially relevant aromatic platform chemicals. The process involves oxidation of alcohol moieties using a gold nanoparticle/hydrotalcite composite, followed by UVA irradiation with TiO2 to decrease the molecular weight of lignin. Characterization of the products confirmed the depolymerization of lignin to smaller molecular weight products. This method offers both energetic and chemical advantages over thermochemical processing for lignin valorisation.
NEW JOURNAL OF CHEMISTRY
(2021)
