Single molecule study of samarium oxide nanoparticles as a purely heterogeneous catalyst for one-pot aldehyde chemistry

2016 ◽  
Vol 6 (19) ◽  
pp. 7113-7121 ◽  
Author(s):  
Gregory K. Hodgson ◽  
Stefania Impellizzeri ◽  
Juan C. Scaiano
Keyword(s):  
Heterogeneous Catalysis ◽  
Homogeneous Catalysis ◽  
Single Molecule ◽  
Metal Ion ◽  
Active Species ◽  
Oxide Nanoparticles ◽  
Samarium Oxide ◽  
One Pot ◽  
Catalytically Active

Heterogeneous catalysis holds distinct advantages over homogeneous catalysis; however, it is only truly advantageous if unaffected by metal ion leaching or in situ formation of a soluble catalytically active species.

scholarly journals Selective hydroboration of unsaturated bonds by an easily accessible heterotopic cobalt catalyst

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chuhan Li ◽  
Shuo Song ◽  
Yuling Li ◽  
Chang Xu ◽  
Qiquan Luo ◽  
...  
Keyword(s):  
Base Metal ◽  
Large Scale ◽  
Metal Cluster ◽  
Active Species ◽  
Cobalt Catalysts ◽  
Metal Salts ◽  
One Pot ◽  
Practical Utilization ◽  
Earth Abundant

AbstractHomogeneous earth-abundant metal catalysis based on well-defined molecular complexes has achieved great advance in synthetic methodologies. However, sophisticated ligand, hazardous activator and multistep synthesis starting from base metal salts are generally required for the generation of active molecular catalysts, which may hinder their broad application in large scale organic synthesis. Therefore, the development of metal cluster catalysts formed in situ from simple earth-abundant metal salts is of importance for the practical utilization of base metal resource, yet it is still in its infancy. Herein, a mixture of catalytic amounts of cobalt (II) iodide and potassium tert-butoxide is discovered to be highly active for selective hydroboration of vinylarenes and dihydroboration of nitriles, affording a good yield of diversified hydroboration products that without isolation can readily undergo further one pot transformations. It should be highlighted that the alkoxide-pinacolborane combination acts as an efficient activation strategy to activate cobalt (II) iodide for the generation of metastable heterotopic cobalt catalysts in situ, which is proposed to be catalytically active species.

scholarly journals A unified view on heterogeneous and homogeneous catalysts through a combination of spectroscopy and quantum chemistry

2016 ◽  
Vol 188 ◽  
pp. 181-197 ◽  
Author(s):  
Dimitrios Maganas ◽  
Annette Trunschke ◽  
Robert Schlögl ◽  
Frank Neese
Keyword(s):  
Heterogeneous Catalysis ◽  
Quantum Chemistry ◽  
Resonance Raman Spectroscopy ◽  
Electronic Spectroscopy ◽  
Open Shell ◽  
Active Species ◽  
Spectroscopic Techniques ◽  
Formidable Challenge ◽  
Catalytically Active ◽  
Unified View

Identifying catalytically active structures or intermediates in homogeneous and heterogeneous catalysis is a formidable challenge. However, obtaining experimentally verified insight into the active species in heterogeneous catalysis is a tremendously challenging problem. Many highly advanced spectroscopic and microscopic methods have been developed to probe surfaces. In this discussion we employ a combination of spectroscopic methods to study two closely related systems from the heterogeneous (the silica-supported vanadium oxide VOx/SBA-15) and homogeneous (the complex K[VO(O2)Hheida]) domains. Spectroscopic measurements were conducted strictly in parallel for both systems and consisted of oxygen K-edge and vanadium L-edge X-ray absorption measurements in conjunction with resonance Raman spectroscopy. It is shown that the full information content of the spectra can be developed through advanced quantum chemical calculations that directly address the sought after structure–spectra relationships. To this end we employ the recently developed restricted open shell configuration interaction theory together with the time-dependent theory of electronic spectroscopy to calculate XAS and rR spectra respectively. The results of the study demonstrate that: (a) a combination of several spectroscopic techniques is of paramount importance in identifying signature structural motifs and (b) quantum chemistry is an extremely powerful guide in cross connecting theory and experiment as well as the homogeneous and heterogeneous catalysis fields. It is emphasized that the calculation of spectroscopic observables provides an excellent way for the critical experimental validation of theoretical results.

Enzyme-based Biohybrid Foams Designed for Biodiesel Production and Continuous Flow Heterogeneous Catalysis

2013 ◽  
Vol 1492 ◽  
pp. 183-188
Author(s):  
Nicolas Brun ◽  
Hervé Deleuze ◽  
Rénal Backov
Keyword(s):  
Heterogeneous Catalysis ◽  
Enzymatic Activity ◽  
Steric Hindrance ◽  
Continuous Flow ◽  
Biodiesel Production ◽  
One Pot ◽  
Flow Device ◽  
The One ◽  
High Enzymatic Activity

ABSTRACTThe one pot-synthesis and use of monolithic biohybrid foams in a continuous flow device reported inhere presents the advantages of covalent stabilization of the enzymes, together with a low steric hindrance between proteins and substrates, an optimized mass transport due to the interconnected macroporous network and a rather simplicity in regard of the column in-situ synthetic path. Those features, concerning transesterification (biodiesel production) enzyme- based catalyzed reaction, provide high enzymatic activity addressed with bio-hybrid catalysts bearing unprecedented endurance of continuous catalysis for a two months period of time.

scholarly journals Pentacarbonylmethylmanganese(I) as a Synthon for Mn(I) Pincer Catalysts

2019 ◽  
Author(s):  
Karthika J. Kadassery ◽  
David Lacy
Keyword(s):  
Active Species ◽  
Substrate Activation ◽  
Catalytically Active ◽  
Metal Ligand

<p>Mn(I) complexes that enable metal-ligand cooperative substrate activation catalyze a range of transformations. Use of MeMn(CO)5 as a synthon in place of typical Mn(CO)5Br was explored and found to be quite versatile, generating catalytically active species in situ by activation of O–H, N–H, and even C–H bonds.<br></p>

scholarly journals Amsacta moorei Entomopoxvirus Expresses an Active Superoxide Dismutase

2004 ◽  
Vol 78 (19) ◽  
pp. 10265-10275 ◽  
Author(s):  
M. N. Becker ◽  
W. B. Greenleaf ◽  
D. A. Ostrov ◽  
R. W. Moyer
Keyword(s):  
Superoxide Dismutase ◽  
Metal Ion ◽  
Metal Ion Binding ◽  
In Situ Gel ◽  
Reading Frame ◽  
Catalytically Active ◽  
Infected Cells ◽  
Group B

ABSTRACT The entomopoxvirus from Amsacta moorei serves as the prototype of the group B entomopoxviruses. One of the interesting genes found in Amsacta moorei entomopoxvirus (AmEPV) is a superoxide dismutase (sod) (open reading frame AMV255). Superoxide dismutases (SODs) catalyze the conversion of superoxide radicals to hydrogen peroxide and oxygen. Many vertebrate poxviruses contain a sod gene, but to date, none have been demonstrated to be active. There are three families of SODs, characterized by their metal ion-binding partners, Fe, Mn, or Cu and Zn. Poxvirus enzymes belong to the Cu-Zn SOD family. Unlike inactive vertebrate poxvirus SODs, AMVSOD contains all the amino acids necessary for function. We expressed and purified a 6X-His-tagged version of the AMVSOD in Escherichia coli. The recombinant AMVSOD demonstrates superoxide dismutase activity both in an in situ gel assay and by stopped flow spectrophotometry. The k cat/K m for AMVSOD is 4 × 107 M−1s−1. In infected cells, the AMVSOD protein behaves as a dimer and is catalytically active; however, disruption of the gene in AMEPV has little or no effect on growth of the virus in cell culture. An analysis of mRNA expression indicates that AMVsod is expressed late during infection of Lymantria dispar (Ld652) cells and produces a discrete nonpolydisperse transcript. Characterization of protein expression with a monoclonal antibody generated against AMVSOD confirms that the AMVSOD protein can be classified as a late, postreplicative gene. Therefore, AMVSOD is the first example of an active poxvirus SOD.

scholarly journals Polymer-grafted gold nanoflowers with temperature-controlled catalytic features by in situ particle growth and polymerization

2019 ◽  
Vol 3 (7) ◽  
pp. 1449-1453 ◽  
Author(s):  
Chaojian Chen ◽  
David Yuen Wah Ng ◽  
Tanja Weil
Keyword(s):  
Particle Growth ◽  
Metal Reduction ◽  
One Pot ◽  
Gold Nanoflowers ◽  
Catalytically Active ◽  
Arget Atrp ◽  
Temperature Controlled

Catalytically active polymer-grafted gold nanoflowers are prepared by combining ARGET ATRP and metal reduction in a one pot reaction.

scholarly journals Pentacarbonylmethylmanganese(I) as a Synthon for Mn(I) Pincer Catalysts

2019 ◽  
Author(s):  
Karthika J. Kadassery ◽  
David Lacy
Keyword(s):  
Active Species ◽  
Substrate Activation ◽  
Catalytically Active ◽  
Metal Ligand

<p>Mn(I) complexes that enable metal-ligand cooperative substrate activation catalyze a range of transformations. Use of MeMn(CO)5 as a synthon in place of typical Mn(CO)5Br was explored and found to be quite versatile, generating catalytically active species in situ by activation of O–H, N–H, and even C–H bonds.<br></p>

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