123-30-8Relevant articles and documents
A New Class of 1-Aryl-5,6-dihydropyrrolo[2,1-a]isoquinoline Derivatives as Reversers of P-Glycoprotein-Mediated Multidrug Resistance in Tumor Cells
Nevskaya, Alisa A.,Matveeva, Maria D.,Borisova, Tatiana N.,Niso, Mauro,Colabufo, Nicola A.,Boccarelli, Angelina,Purgatorio, Rosa,de Candia, Modesto,Cellamare, Saverio,Voskressensky, Leonid G.,Altomare, Cosimo D.
, p. 1588 - 1596 (2018)
A number of aza-heterocyclic compounds, which share the 5,6-dihydropyrrolo[2,1-a]isoquinoline (DHPIQ) scaffold with members of the lamellarin alkaloid family, were synthesized and evaluated for their ability to reverse in vitro multidrug resistance in cancer cells through inhibition of P-glycoprotein (P-gp) and/or multidrug-resistance-associated protein 1. Most of the investigated DHPIQ compounds proved to be selective P-gp modulators, and the most potent modulator, 8,9-diethoxy-1-(3,4-diethoxyphenyl)-3-(furan-2-yl)-5,6-dihydropyrrolo[2,1-a]isoquinoline-2-carbaldehyde, attained sub-micromolar inhibitory potency (IC50: 0.19 μm). Schiff bases prepared by the condensation of some 1-aryl-DHPIQ aldehydes with p-aminophenol also proved to be of some interest, and one of them, 4-((1-(4-fluorophenyl)-5,6-dihydro-8,9-dimethoxypyrrolo[2,1-a]isoquinolin-2-yl)methyleneamino)phenol, had an IC50 value of 1.01 μm. In drug combination assays in multidrug-resistant cells, some DHPIQ compounds, at nontoxic concentrations, significantly increased the cytotoxicity of doxorubicin in a concentration-dependent manner. Studies of structure–activity relationships and investigation of the chemical stability of Schiff bases provided physicochemical information useful for molecular optimization of lamellarin-like cytotoxic drugs active toward chemoresistant tumors as well as nontoxic reversers of P-gp-mediated multidrug resistance in tumor cells.
Green synthesis of the Ag/HZSM-5 nanocomposite by using Euphorbia heterophylla leaf extract: A recoverable catalyst for reduction of organic dyes
Tajbakhsh, Mahmood,Alinezhad, Heshmatollah,Nasrollahzadeh, Mahmoud,Kamali, Taghi A.
, p. 258 - 265 (2016)
During this paper, the Ag/HZSM-5 nanocomposite has been successfully synthesized by using an aqueous extract of Euphorbia heterophylla leaves as a stabilizing and reducing agent. The green synthesized Ag/HZSM-5 nanocomposite was characterized by FT-IR (Fourier transform infrared spectroscopy), FESEM (field emission scanning electron microscopy), EDS (energy dispersion X-ray spectroscopy), UV-vis, XRD (X-ray powder diffraction) and elemental mapping. The Ag/HZSM-5 nanocomposite was found to be efficient nanocatalyst for the reduction of organic dyes such as Methylene blue (MB), Congo red (CR), Rhodamine B (RhB) and 4-nitrophenol (4-NP) in water at room temperature. The catalytic activities of the nanocatalyst in reactions were monitored by using UV-vis spectroscopy. Interestingly, the Ag/HZSM-5 catalyst can be easily recovered and reused several times without any significant loss of catalytic efficiency.
Monooxygenase-like activity of methemoglobin with sodium sulfite as an efficient reductant
Song, Yonghong,Yang, Chi-Ming,Kluger, Ronald
, p. 4365 - 4366 (1993)
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Synthesis of a superparamagnetic ultrathin FeCO3 nanorods-enzyme bionanohybrid as a novel heterogeneous catalyst
Benavente, Rocio,Lopez-Tejedor, David,Palomo, Jose M.
, p. 6256 - 6259 (2018)
Herein we report a straightforward synthesis of an ultrathin protein-iron(ii) carbonate nanorods (FeCO3-NRs) heterogeneous bionanohybrid at room temperature and in aqueous media. The enzyme induced the in situ formation of well-dispersed FeCO3 NRs on a protein network. The addition of NaBH4 as a reducing agent allowed us to obtain nanorods (5 × 40 nm) with superparamagnetic properties. This bionanohybrid showed excellent catalytic results in reduction, oxidation and C-C bond reactions.
Green Route for the Preparation of p-Aminophenol from Nitrobenzene by Catalytic Hydrogenation in Pressurized CO2/H2O System
Zhang, Tingting,Jiang, Jingyang,Wang, Yanhua
, p. 2050 - 2054 (2015)
The preparation of p-aminophenol from nitrobenzene by one-pot catalytic hydrogenation and in situ acid-catalyzed Bamberger rearrangement was first realized in a pressurized CO2/H2O system. By employing Pt-Sn/Al2O3 as catalyst, nitrobenzene could be converted to p-aminophenol with selectivity as high as 85% when the reaction was carried out at 140°C under 5.5 MPa CO2 and 0.2 MPa H2. This new protocol is environmentally benign because it is fully rid of the use of mineral acid by the application of self-neutralizable carbonic acid.
Nickel nanoparticle/carbon catalysts derived from a novel aqueous-synthesized metal-organic framework for nitroarene reduction
Martín-Jimeno, F. Julian,Martínez-Alonso, Amelia,Paredes, Juan I.,Suárez-García, Fabián,Tascón, Juan M. D.
, (2021)
Carbon-supported, non-noble metal-based catalysts derived from metal-organic frameworks (MOFs) are attractive alternatives to noble metal-based systems, but typical syntheses of the starting MOFs are not desirable from an environmental and practical perspective (e.g., they rely on non-innocuous organic solvents and long reaction times). Here, we report the preparation of a Ni-based MOF in aqueous medium, at moderate temperature (95 °C) and in a short reaction time (2 g?1 depending on the carbonization temperature applied to the MOF, as well as high Ni contents (between ～36 and 57 wt%). Notwithstanding the latter, the metal was homogeneously distributed throughout the carbon matrix in the hybrid and was quite resistant to extensive agglomeration and sintering, even at temperatures as high as 1000 °C. With increasing carbonization temperature, the Ni component was seen to go through different crystal phases, i.e., Ni3C phase → Ni hexagonal close-packed phase → Ni face-centered cubic phase. The results of the catalytic tests suggested the former and latter phases to be the most active towards the reduction of 4-NP, with catalytic activity values as high as 0.039 mol4-NP molNi?1 min?1.
Magnetic rod-based metal-organic framework metal composite as multifunctional nanostirrer with adsorptive, peroxidase-like and catalytic properties
Meteku, Benjamin Edem,Huang, Jiankun,Zeng, Jingbin,Aslam, Sobia,Zhang, Yu,Zhang, Xue,Cui, Bingwen,Wen, Cong-ying,Yan, Zifeng
, p. 3245 - 3251 (2021)
Although magnetic stirring is frequently used to enhance the kinetics for adsorption, chemical and biochemical reactions, the introduction of stirrers inevitably leads to the adsorption of analytes and thus interferes with the efficiency of the chemical process or reaction. In this work, magnetic Fe3O4 nanorods with tunable length-to-diameter ratio were synthesized via a hydrothermal method and used as templates for the in-situ depositing of MIL-100(Fe) and gold nanoparticles. Such nanorod-based material can not only function as an adsorbent, nanozyme, and a heterogeneous catalyst for corresponding applications but also serve as a magnetic nanostirrer to enhance kinetics. As a proof-of-concept, the capture of bacteria pathogen, mimic-peroxidase-based colorimetric detection of hydrogen peroxide, and the catalytic reduction of selected organic pollutants were conducted using the as-synthesized Fe3O4@MIL-100(Fe)-Au nanostirrer with and without magnetic field. The results show that the rates of bacteria capture, mimetic enzyme reaction and catalysis were tremendously expedited. We believe this magnetic field-assisted approach holds great promise for future applications, because, not only does it eliminate the use of external magnetic stirrers and thereby decrease the risk of foreign pollution but also, is adaptable for nanoscale reaction systems where conventional stirring is not applicable due to size limitations.
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Matsumura,Sone
, p. 1406 (1931)
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Spectrophotometric determination of paracetamol with microwave assisted alkaline hydrolysis
Xu, Chunli,Li, Baoxin
, p. 1861 - 1864 (2004)
A novel and rapid spectrophotometric method for the determination of paracetamol is proposed in this paper. The proposed method is based on the microwave assisted alkaline hydrolysis of paracetamol to p-aminophenol that reacts with S2- in the presence of Fe3+ as oxidant to produce a methylene blue-like dye having an absorptivity maximum at 540nm. The experiment showed that paracetamol could be hydrolysed quantitatively to p-aminophenol in only 1.5min under radiation power 640W using a microwave in NaOH medium. The system obeys Beer's law in the range of 0-3.0×10 -4moll-1 paracetamol. The molar absorptivity and Sandell's sensitivity were found to be 3.2×103lmol-1cm -1 and 0.047μgcm-2, respectively. The relative standard deviation (n=11) was 1.7% for 8.0×10-5moll-1 paracetamol. The method has been applied successfully to analysis of paracetamol in pharmaceutical preparation.
Highly efficient Au/TiO2 catalyst for one-pot conversion of nitrobenzene to p-aminophenol in water media
Zou, Luyao,Cui, Yuanyuan,Dai, Weilin
, p. 257 - 262 (2014)
Au/TiO2 catalyst is firstly reported to be efficient in the hydrogenation of nitrobenzene to produce p-aminophenol with a high PAP selectivity of 81% and overall yield more than 63%. The catalyst is also quite stable and can be reused for at least 4 times with only slight decrease in activity.
Carbonization of Co-BDC MOF results in magnetic C@Co nanoparticles that catalyze the reduction of methyl orange and 4-nitrophenol in water
Ahsan, Md. Ariful,Fernandez-Delgado, Olivia,Deemer, Eva,Wang, Huiyao,El-Gendy, Ahmed A.,Curry, Michael L.,Noveron, Juan C.
, (2019)
Herein we report a simple, facile and green technique for the preparation of magnetic cobalt nanoparticles (NPs) embedded on porous carbon (C@Co) nanocatalyst using MOFs template and explored for the catalytic reduction of Methyl orange (MO) and 4-Nitroph
Ir/C and Brφnsted acid functionalized ionic liquids an efficient catalytic system for hydrogenation of nitrobenzene to: P -aminophenol
Wang, Hong,Jiang, Taotao,Ma, Lei,Wang, Hanbing,Xu, Xiaoliang,Lu, Chunshan,Li, Xiaonian
, p. 31663 - 31670 (2017)
In this study, we found that the phenylhydroxylamine intermediate could desorb more easily from an Ir surface than from a Pt surface, which is beneficial for inhibiting the over-hydrogenation of phenylhydroxylamine to aniline. On the other hand, the Brφnsted acid functionalized ionic liquids with sulfonic acid and bisulfate anions were acidic enough to catalyze the Bamberger rearrangement to form p-aminophenol from phenylhydroxylamine. On this basis, a new catalytic system constructed by Ir/C and Brφnsted acid functionalized ionic liquid was applied, for the first time, to the one-pot hydrogenation of nitrobenzene to p-aminophenol. Our results indicate that the PAP selectivity of Ir/C and [SO3H-bmim][HSO4] Brφnsted functionalized ionic liquid was far more than that of the traditional Pt/C and sulfuric acid catalyst system. Furthermore, the dually functionalized ionic liquid ([HSO3-b-N-Bu3][HSO4]) can be used simultaneously as an acid catalyst and also as a surfactant, due to its higher lipophilicity. Therefore, our new catalytic system has unique advantages in the hydrogenation of nitrobenzene to p-aminophenol.
Adsorption driven formate reforming into hydride and tandem hydrogenation of nitrophenol to amine over PdO: Xcatalysts
Zhu, Xiaohui,Liang, Shipan,Chen, Shuang,Liu, Xiangdong,Li, Renhong
, p. 8332 - 8338 (2020)
Due to their high toxicity and non-biodegradability, efficient reduction of nitroarenes to amines is of great practical importance, yet it still remains a significant challenge. Herein, we report PdO/PdO2 nanoparticles uniformly supported on titanate nanotubes (PdOx/TiNTs) for catalyzing the tandem dehydrogenation of sodium formate (SF) and hydrogenation of p-nitrophenol (PNP) to p-aminophenol (PAmP) under mild conditions. Notably, SF adsorption is mainly driven by the hydrogen bonding interactions between the H atom in SF and surface Pd sites, which factually makes the interface of PdOx/TiNT-SF an effective platform for C-H activation. Meanwhile, it is also found that the efficiency of the hydrogenation reaction depends on the reduction rate of the nitro group to nitroso group, and the O atoms adjacent to Pd are considered as the essential sites that facilitate this process. On the basis of the above two effects, the PdOx/TiNT catalyst shows unprecedented catalytic activity (turnover frequency, TOF, is 45.6 h-1) and good selectivity (～100%) during PNP reduction at room temperature. This work deepens our understanding on tandem catalytic (de)hydrogenation systems, and will benefit the design of heterogeneous catalysts for the production of industrially important chemicals.
Kinetic rotating droplet electrochemistry: A simple and versatile method for reaction progress kinetic analysis in microliter volumes
Challier, Lylian,Miranda-Castro, Rebeca,Marchal, Damien,Noel, Vincent,Mavre, Francois,Limoges, Benoiit
, p. 14215 - 14228 (2013)
Here, we demonstrate a new generic, affordable, simple, versatile, sensitive, and easy-to-implement electrochemical kinetic method for monitoring, in real time, the progress of a chemical or biological reaction in a microdrop of a few tens of microliters, with a kinetic time resolution of ca. 1 s. The methodology is based on a fast injection and mixing of a reactant solution (1-10 μL) in a reaction droplet (15-50 μL) rapidly rotated over the surface of a nonmoving working electrode and on the recording of the ensuing transient faradaic current associated with the transformation of one of the components. Rapid rotation of the droplet was ensured mechanically by a rotating rod brought in contact atop the droplet. This simple setup makes it possible to mix reactants efficiently and rotate the droplet at a high spin rate, hence generating a well-defined hydrodynamic steady-state convection layer at the underlying stationary electrode. The features afforded by this new kinetic method were investigated for three different reaction schemes: (i) the chemical oxidative deprotection of a boronic ester by H2O2, (ii) a biomolecular binding recognition between a small target and an aptamer, and (iii) the inhibition of the redox-mediated catalytic cycle of horseradish peroxidase (HRP) by its substrate H2O2. For the small target/aptamer binding reaction, the kinetic and thermodynamic parameters were recovered from rational analysis of the kinetic plots, whereas for the HRP catalytic/inhibition reaction, the experimental amperometric kinetic plots were reproduced from numerical simulations. From the best fits of simulations to the experimental data, the kinetics rate constants primarily associated with the inactivation/reactivation pathways of the enzyme were retrieved. The ability to perform kinetics in microliter-size samples makes this methodology particularly attractive for reactions involving low-abundance or expensive reagents.
Synthesis of glucose-mediated Ag-γ-Fe2O3 multifunctional nanocomposites in aqueous medium - a kinetic analysis of their catalytic activity for 4-nitrophenol reduction
Kaloti, Mandeep,Kumar, Anil,Navani, Naveen K.
, p. 4786 - 4799 (2015)
This paper reports the synthesis of γ-Fe2O3 supported Ag nanoparticles (NPs) in aqueous medium by following a green approach. The presence of Fe2O3 in the gamma phase and silver in the nanocomposite has been confirmed by Raman spectroscopy, EDAX and XPS analyses. The presence of Ag in the nanocomposite is also indicated by UV spectroscopy. In the process of in situ generation of glucose mediated Ag NPs on the γ-Fe2O3 matrix, the size of γ-Fe2O3 nanoclusters reduced from 11.6 ± 1.6 to 9 ± 1 nm as was estimated from HRTEM analysis. Glucose served as an effective stabilizer for both Ag and γ-Fe2O3 in the nanocomposite. At lower concentrations of Ag (0.15-1.2 μM) the reduction of 4-nitrophenol (4-Nip) follows pseudo-first-order kinetics and the second order rate constant for this process was found to be 5.28 × 103 dm3 mol-1 s-1. Whereas, at higher concentrations (3.2-28.9 μM), it follows zero-order kinetics and occurred with a rate constant of 1 × 10-2 mol dm-3 s-1. The amount of silver in the nanocomposite is found to influence the kinetics of the catalytic reduction in a complex scheme following the Langmuir-Hinshelwood mechanism. The recyclability of the as-synthesized nanocomposite up to 7 cycles and the catalytic effect even at a very low silver concentration (0.15 μM) associated with high surface area and superparamagnetism suggest it to be a cost effective and environmentally friendly potential catalytic system.
Magnetic Fe3O4/graphene oxide/copper-based nanocomposite as a reusable catalyst for the reduction of 4-nitrophenol
Zabihzadeh, Mehdi,Shirini, Farhad,Tajik, Hassan,Shokri, Zahra,Karami, Shiva
, p. 121 - 127 (2020)
In the present investigation, Fe3O4/Graphene oxide/Pr–NH2–CuII was reported as a novel magnetically recoverable nanocomposite and characterized using various analytical techniques such as FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and inductively coupled plasma (ICP). The catalytic performance of the synthesized catalyst was evaluated in the reduction of 4-nitrophenol to 4-aminophenol by an excess amount of sodium borohydride as the source of hydrogen in aqueous solution. The reaction was monitored by UV-vis spectroscopy at ambient temperature. Magnetic nature of the catalyst led to its simple recovery by a permanent magnet and excellent recyclability without appreciable loss of the catalytic activity.
Gold-Catalyzed Dearomative Spirocyclization of N-Aryl Alkynamides for the Synthesis of Spirolactams
Vacala, Taylor L.,Carlson, Paul R.,Arreola-Hester, Asa,Williams, Chloé G.,Makhoul, Evana W.,Vadola, Paul A.
, p. 1493 - 1501 (2018)
A catalytic redox-neutral method for the synthesis of spirolactams proceeding through the dearomative spirocyclization of N-aryl alkynamides is reported. In contrast to stoichiometric activating agents employed for related transformations, we show that the use of 5 mol % of Au(PPh3)Cl and AgOTf in dichloroethane at 50-80 °C leads to selective spirocyclization, furnishing the products in yields of 35-87%. The substrate scope of the reaction is good, with both electron-donating and electron-withdrawing groups being tolerated around the arene ring, as well as substitution at the amide nitrogen. The identity of the para-alkoxy group on the arene ring is key to achieving selectivity for spirocyclization over alternative mechanistic pathways. While the presence of a para-methoxy group leads to trace amounts of the desired spirolactams, the para-tert-butoxy or para-hydroxy substrate analogues furnish the spirolactams in good yield with high selectivity.
Preparation of bimetallic metal-organic framework microflowers by spray method
Zhang, Liying,Li, Linlin,Bai, Xiaojue,Xia, Mingjian,Shao, Lei,Wang, Tieqiang,Zhang, Xuemin,Li, Yunong,Qi, Xuan,Fu, Yu
, p. 175 - 177 (2019)
The NiCo-MOF microflowers are fabricated by a rapid spray method, which are assembled by 2D NiCo-MOF nanosheets with uniform crystal morphology and homogeneous dispersion of Ni and Co. Because of their large exposed active sites and nanoscale thickness, the NiCo-MOF microflowers exhibit good catalytic performance for the reduction of 4-nitrophenol.
Transfer Hydrogenation of Nitroarenes Catalyzed by CoCu Anchored on Nitrogen-doped Porous Carbon
Liu, Xiaotong,Zhang, Longkang,Wang, Junmin,Shang, Ningzhao,Gao, Shutao,Wang, Chun,Gao, Yongjun
, (2020)
The non-precious metal catalysts with high catalytic activity is extremely desirable but still full of challenges. In this paper, CoCu bimetal immobilized on nitrogen-doped porous carbon (CoCu-N-C) was prepared by an effective ligand-stabilized pyrolysis strategy. CoCu-N-C exhibited excellent catalytic efficiency for the transfer hydrogenation of nitroarenes with ammonia borane as hydrogen source, which can be ascribed to the well dispersed metal nanoparticles, the synergetic interaction of CoCu bimetal and nitrogen-doped carbon. The durability and recyclability experiments of the recycled CoCu-N-C catalyst indicated that no obvious change in catalytic performance was observed after five consecutive cycles. To gain insight into the catalytic mechanism of CoCu-N-C for the hydrogenation reaction, density functional theory calculations was also conducted. This work provides an universal approach for constructing highly efficient non-precious metal heterogeneous catalysts and which may find diverse high performance applications.
Flavhemoglobin: A Semisyntheic Hydroxylase Acting in the Absence of Reductase
Kokubo, Toshio,Sassa, Shigeru,Kaiser, E. T.
, p. 606 - 607 (1987)
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Synthesis of p-aminophenol by catalytic hydrogenation of nitrobenzene
Rode,Vaidya,Chaudhari
, p. 465 - 470 (1999)
The present work describes the preparation of p-aminophenol via single-step catalytic hydrogenation of nitrobenzene in acid medium. A conventional method of synthesis of p-aminophenol is a two-step reaction involving iron-acid reduction of p-nitrophenol. This method causes serious effluent disposal problems due to the stoichiometric use of iron-acid, which leads to the formation of Fe-FeO sludge (?2 kg/kg of product) in the process, which cannot be recycled. The single-step hydrogenation of nitrobenzene was carried out using platinum catalyst, and the process conditions were optimized. Complete conversion of nitrobenzene was achieved with selectivity to p-aminophenol as high as 75% under the best set of conditions. Furthermore, the catalyst can be easily recovered and efficiently recycled giving the TON as high as 1.38 κ' 10.5 This paper presents studies on the effect of various process parameters such as temperature, hydrogen pressure, and substrate and acid concentration on the rate of reaction and selectivity to p-aminophenol.
Contrasting effect of isoflurane on drug metabolism: Decreased type I and increased type II substrate metabolism in guinea pig liver microsomes
Mustafizur Rahman,Fujii, Kohyu,Kawamoto, Masashi,Yuge, Osafumi
, p. 331 - 337 (1996)
Inhalation anaesthetics might affect perioperative drug elimination by altering drug distribution, hepatic blood flow or drug metabolism. The in vitro effects of isoflurane on aniline hydroxylation and aminopyrine N-demethylation were investigated with guinea pig liver microsomes to assess the role of isoflurane on oxidative drug metabolism through the hepatic mixed-function oxidase system, p-Aminophenol and formaldehyde were measured spectrophotometrically as metabolic products of aniline hydroxylation and aminopyrine N-demethylation, respectively, where the reaction mixture consisted of a microsomal suspension, NADPH, aminopyrine or aniline, with or without isoflurane. The rate of cytochrome P-450 reduction by NADPH affected in the presence of isoflurane was investigated by spectrometric measurement of the CO-cytochrome P-450 complex formation at various times. Due to the addition of isoflurane, the V(max) values for aniline hydroxylation evidently increased except in high isoflurane concentration (3.33 mM) and for aminopyrine N-demethylation the value was significantly low only in the presence of a high isoflurane concentration, whereas the K(m) values significantly decreased in aniline hydroxylation and increased in aminopyrine N-demethylation, and isoflurane also accelerated the rate of cytochrome P-450 reduction by NADPH. These results reflect the inhibition of aminopyrine N-demethylation and activation of aniline hydroxylation in the presence of isoflurane as a consequence of isoflurane-accelerated cytochrome P-450 reduction by NADPH and/or drug-enzyme binding properties, and may have implications on the metabolism of perioperatively administered drugs during isoflurane anaesthesia.
Designed Meso-macroporous Silica Framework Impregnated with Copper Oxide Nanoparticles for Enhanced Catalytic Performance
Kanwar, Rohini,Bhar, Rekha,Mehta, Surinder Kumar
, p. 2087 - 2095 (2018)
The template efficacy of solid lipid nanoparticles for generating porous silica materials with the amalgamation of Cu-functionalized cetylpyridinium chloride (CPC; as a co-emulsifier and as a metal source for generation of CuO oxide nanoparticles) has bee
Catalytically Active Bimetallic Nanoparticles Supported on Porous Carbon Capsules Derived from Metal-Organic Framework Composites
Yang, Hui,Bradley, Siobhan J.,Chan, Andrew,Waterhouse, Geoffrey I. N.,Nann, Thomas,Kruger, Paul E.,Telfer, Shane G.
, p. 11872 - 11881 (2016)
We report a new methodology for producing monometallic or bimetallic nanoparticles confined within hollow nitrogen-doped porous carbon capsules. The capsules are derived from metal-organic framework (MOF) crystals that are coated with a shell of a secondary material comprising either a metal-tannic acid coordination polymer or a resorcinol-formaldehyde polymer. Platinum nanoparticles are optionally sandwiched between the MOF core and the shell. Pyrolysis of the MOF-shell composites produces hollow capsules of porous nitrogen-doped carbon that bear either monometallic (Pt, Co, and Ni) or alloyed (PtCo and PtNi) metal nanoparticles. The Co and Ni components of the bimetallic nanoparticles are derived from the shell surrounding the MOF crystals. The hollow capsules prevent sintering and detachment of the nanoparticles, and their porous walls allow for efficient mass transport. Alloyed PtCo nanoparticles embedded in the capsule walls are highly active, selective, and recyclable catalysts for the hydrogenation of nitroarenes to anilines.
High amplification rates from the association of two enzymes confined within a nanometric layer immobilized on an electrode: Modeling and illustrating example
Limoges, Benoit,Marchal, Damien,Mavre, Francois,Saveant, Jean-Michel
, p. 6014 - 6015 (2006)
Electrochemical responses (e.g., chronoamperometric) obtained with an immobilized enzyme that produces an electroactive species may be used to quantitate the amount of enzyme or the concentration of its substrate. It is shown, on theoretical and experimental bases, that product-to-substrate coupling with a second enzyme co-immobilized with the first within one or within a small number of monolayers, allows high amplification rates (higher than 1000), avoids membrane transport limitations, and lends itself to precise kinetic analyses that provide guidelines for optimization of the analytical sensitivity. Very large amplification factors, as large as several thousands, can be reached experimentally, in agreement with appropriately derived theoretical predictions, thus opening the route to the rational design of high-performance substrate sensing or affinity assays applications. Copyright
Nickel Boride Catalyzed Reductions of Nitro Compounds and Azides: Nanocellulose-Supported Catalysts in Tandem Reactions
Proietti, Giampiero,Prathap, Kaniraj Jeya,Ye, Xinchen,Olsson, Richard T.,Dinér, Peter
supporting information, p. 133 - 146 (2021/11/04)
Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of organic azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced, and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.
Surface Roughness Effects of Pd-loaded Magnetic Microspheres on Reduction Kinetics of Nitroaromatics
An, Seonghwi,Manivannan, Shanmugam,Viji, Mayavan,Shim, Min Suk,Hwang, Byeong Hee,Kim, Kyuwon
supporting information, p. 894 - 899 (2021/05/06)
Metal nanoparticles decoration on magnetically active semiconductor materials is a common strategy to improve the colloidal stability, catalyst harvesting, and reuse. In this study, a surfactant-free solvothermal method followed by a heat treatment to pre
