86-81-7Relevant articles and documents
Highly dispersed cobalt oxide nanoparticles on manganese oxide nanotubes for aerobic oxidation of benzyl alcohol
Reddy, Velma Ganga,Jampaiah, Deshetti,Chalkidis, Anastasios,Sabri, Ylias M.,Mayes, Edwin L.H.,Bhargava, Suresh K.
, (2019)
Hybrid Co3O4/MnO2 nanotube-based catalysts were prepared by a simple hydrothermal synthesis method. The physico-chemical properties of Co3O4/MnO2 catalyst were then studied by different characterization techniques, namely, SEM, TEM and HR-TEM, XRD, BET surface area, XPS and H2-TPR. The hybrid catalyst showed superior catalytic performance toward benzyl alcohol oxidation than pure MnO2 nanotubes and Co3O4 nanoparticles. The uniform dispersion of Co3O4 nanoparticles, good redox behaviour, the variable oxidation states of manganese and cobalt (Mn3+/4+ or Co3+/2+) as well as the abundance of active surface oxygen species were responsible for such a high catalytic activity.
Aerobic oxidation of alcohols catalyzed by rhodium(iii) porphyrin complexes in water: Reactivity and mechanistic studies
Liu, Lianghui,Yu, Mengmeng,Wayland, Bradford B.,Fu, Xuefeng
, p. 6353 - 6355 (2010)
Selective oxidation of alcohol in water using molecular oxygen as the terminal oxidant is mediated by rhodium porphyrin complexes. Addition of methanol to an aqueous solution of (TSPP)Rh(iii) resulted in observation of the key intermediate porphyrin rhodium(iii) methoxide species. The activation parameters for βC-H elimination of Rh-alkoxide were evaluated.
Reversible Redox Activity in Multicomponent Metal-Organic Frameworks Constructed from Trinuclear Copper Pyrazolate Building Blocks
Tu, Binbin,Pang, Qingqing,Xu, Huoshu,Li, Xiaomin,Wang, Yulin,Ma, Zhen,Weng, Linhong,Li, Qiaowei
, p. 7998 - 8007 (2017)
Inorganic functionalization of metal-organic frameworks (MOFs), such as incorporation of multiple inorganic building blocks with distinct metals into one structure and further modulation of the metal charges, endows the porous materials with significant properties toward their applications in catalysis. In this work, by an exploration of the role of 4-pyrazolecarboxylic acid (H2PyC) in the formation of trinuclear copper pyrazolate as a metalloligand in situ, four new MOFs with multiple components in order were constructed through one-pot synthesis. This metalloligand strategy provides multicomponent MOFs with new topologies (tub for FDM-4 and tap for FDM-5) and is also compatible with a second organic linker for cooperative construction of complex MOFs (1,4-benzenedicarboxylic acid for FDM-6 and 2,6-naphthalenedicarboxylic acid for FDM-7). The component multiplicity of these MOFs originates from PyC's ability to separate Cu and Zn on the basis of their differentiated binding affinities toward pyrazolate and carboxylate. These MOFs feature reversible and facile redox transformations between CuI3(PyC)3 and CuII3(μ-OH)(PyC)3(OH)3 without altering the connecting geometries of the units, thus further contributing to the significant catalytic activities in the oxidation of CO and aromatic alcohols and the decomposition of H2O2. This study on programming multiple inorganic components into one framework and modulating their electronic structures is an example of functionalizing the inorganic units of MOFs with a high degree of control.
Insight into highly selective photocatalytic oxidation of alcohols by a new trinuclear ruthenium complex with visible light
Chao, Duobin,Fu, Wen-Fu
, p. 306 - 310 (2014)
A new ligand bearing two tpy moieties and one bpy unit (tpy = 2,2′:6′,2′′-terpyridine; bpy = 2,2′-bipyridine) linked by carbon-carbon single bonds and its corresponding trinuclear ruthenium complex were readily synthesized in high yield, and characterized by 1H NMR spectroscopy, high-resolution electrospray ionization mass spectrometry (HR-ESI/MS) and elemental analysis. The ruthenium complex exhibited moderate catalytic activity towards selective oxidation of alcohols in water with visible light under an air atmosphere. Investigations of UV/vis spectra, electrochemistry and ESI/MS suggested that the catalytic cycle involves two processes, RucII-OH2/Ruc III-OH and RucIII-OH/Ruc IVO. The effective electron transfer from the excited state *[Ru(tpy)2]2+ to [Co(NH3) 5Cl]Cl2 is proposed to be responsible for the good activities of this visible-light-driven system under an air atmosphere.
Polyaniline supported vanadium catalyzed aerobic oxidation of alcohols to aldehydes and ketones
Reddy, Sabbasani Rajasekhara,Das, Subhabrata,Punniyamurthy
, p. 3561 - 3564 (2004)
Polyaniline supported vanadium complex 1 catalyzes efficiently the oxidation of alcohols to aldehydes and ketones in high yields under molecular oxygen in toluene at ca. 100°C. The catalyst 1 can be recycled without loss of activity.
Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
supporting information, p. 2048 - 2053 (2022/03/31)
A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
One-Pot Biocatalytic In Vivo Methylation-Hydroamination of Bioderived Lignin Monomers to Generate a Key Precursor to L-DOPA
Birmingham, William R.,Galman, James L.,Parmeggiani, Fabio,Seibt, Lisa,Turner, Nicholas J.
, (2022/01/13)
Electron-rich phenolic substrates can be derived from the depolymerisation of lignin feedstocks. Direct biotransformations of the hydroxycinnamic acid monomers obtained can be exploited to produce high-value chemicals, such as α-amino acids, however the reaction is often hampered by the chemical autooxidation in alkaline or harsh reaction media. Regioselective O-methyltransferases (OMTs) are ubiquitous enzymes in natural secondary metabolic pathways utilising an expensive co-substrate S-adenosyl-l-methionine (SAM) as the methylating reagent altering the physicochemical properties of the hydroxycinnamic acids. In this study, we engineered an OMT to accept a variety of electron-rich phenolic substrates, modified a commercial E. coli strain BL21 (DE3) to regenerate SAM in vivo, and combined it with an engineered ammonia lyase to partake in a one-pot, two whole cell enzyme cascade to produce the l-DOPA precursor l-veratrylglycine from lignin-derived ferulic acid.
Visible-Light-Induced Selective C-C Bond Cleavage Reactions of Dimeric β-O-4 and β-1 Lignin Model Substrates Utilizing Amine-Functionalized Fullerene
Cho, Dae Won,Jang, Hannara,Kim, Min-Ji,Kim, Young-Il,Lim, Dong Hyun,Lim, Suk Hyun,Wee, Kyung-Ryang
, p. 2289 - 2300 (2022/02/07)
Finding a selective and efficient fragmentation process under ambient conditions is pivotal for the generation of fuels and chemical feedstocks from lignoceullosic biomass. In the present study, visible-light and amine-functionalized fullerene-based photocatalyst-promoted photodegradation reactions of dimeric β-O-4 and β-1 lignin model compounds, containing varying numbers of methoxy substituents on the arene ring, were explored to find and develop mild, eco-friendly photochemical techniques for efficient delignification. The results showed that, in contrast to well-known organic photoredox catalysts, amine-functionalized fullerene photocatalyst promoted photochemical reactions of lignin model compounds could lead to more efficient lignin fragmentation reactions through a pathway involving a selective Cα-Cβ bond cleavage process, and in addition, Cα-hydroxyl moiety in lignin model compounds played a significant role in the success of the Cα-Cβ bond cleavage reaction of lignin model substrates.
Atomically Dispersed Pt-N3C1Sites Enabling Efficient and Selective Electrocatalytic C-C Bond Cleavage in Lignin Models under Ambient Conditions
Cui, Tingting,Ma, Lina,Wang, Shibin,Ye, Chenliang,Liang, Xiao,Zhang, Zedong,Meng, Ge,Zheng, Lirong,Hu, Han-Shi,Zhang, Jiangwei,Duan, Haohong,Wang, Dingsheng,Li, Yadong
supporting information, p. 9429 - 9439 (2021/07/19)
Selective cleavage of C-C linkages is the key and a challenge for lignin degradation to harvest value-added aromatic compounds. To this end, electrocatalytic oxidation presents a promising technique by virtue of mild reaction conditions and strong sustainability. However, the existing electrocatalysts (traditional bulk metal and metal oxides) for C-C bond oxidative cleavage suffer from poor selectivity and low product yields. We show for the first time that atomically dispersed Pt-N3C1sites planted on nitrogen-doped carbon nanotubes (Pt1/N-CNTs), constructed via a stepwise polymerization-carbonization-electrostatic adsorption strategy, are highly active and selective toward Cα-Cβbond cleavage in β-O-4 model compounds under ambient conditions. Pt1/N-CNTs exhibits 99% substrate conversion with 81% yield of benzaldehyde, which is exceptional and unprecedented compared with previously reported electrocatalysts. Moreover, Pt1/N-CNTs using only 0.41 wt % Pt achieved a much higher benzaldehyde yield than those of the state-of-the-art bulk Pt electrode (100 wt % Pt) and commercial Pt/C catalyst (20 wt % Pt). Systematic experimental investigation together with density functional theory (DFT) calculation suggests that the superior performance of Pt1/N-CNTs arises from the atomically dispersed Pt-N3C1sites facilitating the formation of a key Cβradical intermediate, further inducing a radical/radical cross-coupling path to break the Cα-Cβbond. This work opens up opportunities in lignin valorization via a green and sustainable electrochemical route with ultralow noble metal usage.
Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
supporting information, p. 6148 - 6152 (2021/08/03)
A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
