Rational Design of Highly Active “Hybrid” Phosphine–Phosphinite Pincer Iridium Catalysts for Alkane Metathesis

ACS Catalysis ◽  
2013 ◽  
Vol 3 (11) ◽  
pp. 2505-2514 ◽  
Author(s):  
Agnieszka J. Nawara-Hultzsch ◽  
Jason D. Hackenberg ◽  
Benudhar Punji ◽  
Carolyn Supplee ◽  
Thomas J. Emge ◽  
...  
Keyword(s):  
Rational Design ◽  
Iridium Catalysts ◽  
Highly Active ◽  
Alkane Metathesis

Rational Design and Synthesis of Highly Active Pincer-Iridium Catalysts for Alkane Dehydrogenation

2009 ◽  
Vol 28 (18) ◽  
pp. 5432-5444 ◽  
Author(s):  
Sabuj Kundu ◽  
Yuriy Choliy ◽  
Gao Zhuo ◽  
Ritu Ahuja ◽  
Thomas J. Emge ◽  
...  
Keyword(s):  
Rational Design ◽  
Iridium Catalysts ◽  
Alkane Dehydrogenation ◽  
Design And Synthesis ◽  
Highly Active

scholarly journals Facet-Dependent Reactivity of Ceria Nanoparticles Exemplified by CeO2-Based Transition Metal Catalysts: A Critical Review

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 452
Author(s):  
Michalis Konsolakis ◽  
Maria Lykaki
Keyword(s):  
Transition Metal ◽  
Co Oxidation ◽  
Critical Review ◽  
Rational Design ◽  
Metal Catalysts ◽  
Co2 Hydrogenation ◽  
Transition Metal Catalysts ◽  
Fine Tuning ◽  
Ceria Nanoparticles ◽  
Highly Active

The rational design and fabrication of highly-active and cost-efficient catalytic materials constitutes the main research pillar in catalysis field. In this context, the fine-tuning of size and shape at the nanometer scale can exert an intense impact not only on the inherent reactivity of catalyst’s counterparts but also on their interfacial interactions; it can also opening up new horizons for the development of highly active and robust materials. The present critical review, focusing mainly on our recent advances on the topic, aims to highlight the pivotal role of shape engineering in catalysis, exemplified by noble metal-free, CeO2-based transition metal catalysts (TMs/CeO2). The underlying mechanism of facet-dependent reactivity is initially discussed. The main implications of ceria nanoparticles’ shape engineering (rods, cubes, and polyhedra) in catalysis are next discussed, on the ground of some of the most pertinent heterogeneous reactions, such as CO2 hydrogenation, CO oxidation, and N2O decomposition. It is clearly revealed that shape functionalization can remarkably affect the intrinsic features and in turn the reactivity of ceria nanoparticles. More importantly, by combining ceria nanoparticles (CeO2 NPs) of specific architecture with various transition metals (e.g., Cu, Fe, Co, and Ni) remarkably active multifunctional composites can be obtained due mainly to the synergistic metalceria interactions. From the practical point of view, novel catalyst formulations with similar or even superior reactivity to that of noble metals can be obtained by co-adjusting the shape and composition of mixed oxides, such as Cu/ceria nanorods for CO oxidation and Ni/ceria nanorods for CO2 hydrogenation. The conclusions derived could provide the design principles of earth-abundant metal oxide catalysts for various real-life environmental and energy applications.

Electrochemical oxidation of 5-hydroxymethylfurfural on ternary metal-organic frameworks nanoarrays: enhancement from electronic structure modulation

2021 ◽  
Author(s):  
Xiaojue Bai ◽  
Wenxiu He ◽  
Xingyu Lu ◽  
Yu Fu ◽  
Wei Qi
Keyword(s):  
Electronic Structure ◽  
Carboxylic Acid ◽  
Electrochemical Oxidation ◽  
Rational Design ◽  
Metal Organic Frameworks ◽  
Highly Active ◽  
Ternary Metal ◽  
Metal Organic ◽  
Structure Modulation

The rational design and exploitation of highly active and stable catalysts for the electrochemical oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to valuable chemical 2,5-furandi-carboxylic acid (FDCA), is of great significance. Herein,...

scholarly journals The role of side chains in the interaction of new antitumor pyrimidoacridinetriones with DNA: molecular dynamics simulations.

2000 ◽  
Vol 47 (1) ◽  
pp. 47-57 ◽  
Author(s):  
J Mazerski ◽  
I Antonini ◽  
S Martelli
Keyword(s):  
Molecular Dynamics ◽  
Rational Design ◽  
Md Simulations ◽  
Ring System ◽  
Side Chain ◽  
Side Chains ◽  
Intercalation Complex ◽  
Highly Active ◽  
Simulation Techniques ◽  
Dynamics Simulations

Pyrimidoacridinetriones (PATs) are a new group of highly active antitumor compounds. It seems reasonable to assume that, like for some other acridine derivatives, intercalation into DNA is a necessary, however not a sufficient condition for antitumor activity of these compounds. Rational design of new compounds of this chemotype requires knowledge about the structure of the intercalation complex, as well as about interactions responsible for its stability. Computer simulation techniques such as molecular dynamics (MD) may provide valuable information about these problems. The results of MD simulations performed for three rationally selected PATs are presented in this paper. The compounds differ in the number and position of side chains. Each of the compounds was simulated in two systems: i) in water, and ii) in the intercalation complex with the dodecamer duplex d(GCGCGCGCGCGC)2. The orientation of the side chain in relation to the ring system is determined by the position of its attachment. Orientation of the ring system inside the intercalation cavity depends on the number and position of side chain(s). The conformations of the side chain(s) of all PATs studied in the intercalation complex were found to be very similar to those observed in water.

Effective Monofunctional Azaphthalocyanine Photosensitizers for Photodynamic Therapy

2009 ◽  
Vol 62 (5) ◽  
pp. 425 ◽  
Author(s):  
Petr Zimcik ◽  
Miroslav Miletin ◽  
Veronika Novakova ◽  
Kamil Kopecky ◽  
Marcela Nejedla ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Carboxy Group ◽  
Rational Design ◽  
Photophysical Properties ◽  
Active Part ◽  
Third Generation ◽  
Highly Active ◽  
Low Degree ◽  
Band Absorption ◽  
Group B

In this work we present a rational design of the active part of third generation photosensitizers for photodynamic therapy based on phthalocyanine and an azaphthalocyanine core. The preferred zinc complexes of the AAAB type that contain bulky tert-butylsulfanyl substituents (A) and one carboxy group (B) have been synthesized by statistical condensation and fully characterized. The tetramerization was performed using magnesium(ii) butoxide followed by demetalation and insertion of ZnII. Compound 1 synthesized from 4,5-bis(tert-butylsulfanyl)phthalonitrile (A) and 2,3-dicyanoquinoxaline-6-carboxylic acid (B) exerted very promising photophysical properties (Q-band absorption at 726 nm, ϵ = 140000 M–1 cm–1), which allowed strong absorption of light at long wavelengths where the penetration of the light through human tissues is deeper. The very high singlet oxygen quantum yield of 1 (ΦΔ = 0.80) assures efficient photosensitization. As a result of bulky peripheral substituents, compound 1 shows good solubility in organic solvents with a low degree of aggregation, which makes it potentially viable for non-complicated modification. One carboxy group in the final structure of 1 allows simple binding to possible carriers. This compound is suitable for binding to targeting moieties to form the highly active part of a third-generation photosensitizer.

scholarly journals Reaction: Rational Design of Highly Active Photocatalysts for CO2 Conversion

Chem ◽  
2020 ◽  
Vol 6 (5) ◽  
pp. 1039-1040 ◽  
Author(s):  
Yang Xia ◽  
Jiaguo Yu
Keyword(s):  
Rational Design ◽  
Co2 Conversion ◽  
Highly Active

Rational design of ordered Pd–Pb nanocubes as highly active, selective and durable catalysts for solvent-free benzyl alcohol oxidation

Nanoscale ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 5145-5150 ◽  
Author(s):  
Chongyang Tang ◽  
Nan Zhang ◽  
Qi Shao ◽  
Xiaoqing Huang ◽  
Xiangheng Xiao
Keyword(s):  
Benzyl Alcohol ◽  
Rational Design ◽  
Alcohol Oxidation ◽  
Solvent Free ◽  
Benzyl Alcohol Oxidation ◽  
Highly Active ◽  
Better Than

Ordered Pd–Pb nanocubes (NCs) were adopted as efficient heterocatalysts for the selective benzyl alcohol oxidation. Due to the ordered phase and well-defined surface, the Pd–Pb NCs can achieve superior activity and selectivity, better than those of other catalysts as we prepared.

scholarly journals Rational design of highly active sgRNAs for CRISPR-Cas9–mediated gene inactivation

2014 ◽  
Vol 32 (12) ◽  
pp. 1262-1267 ◽  
Author(s):  
John G Doench ◽  
Ella Hartenian ◽  
Daniel B Graham ◽  
Zuzana Tothova ◽  
Mudra Hegde ◽  
...  
Keyword(s):  
Rational Design ◽  
Gene Inactivation ◽  
Highly Active

scholarly journals Direct interactions with commensal streptococci modify intercellular communication behaviors of Streptococcus mutans

2020 ◽  
Author(s):  
Justin R. Kaspar ◽  
Kyulim Lee ◽  
Brook Richard ◽  
Alejandro R. Walker ◽  
Robert A. Burne
Keyword(s):  
Gene Expression ◽  
Streptococcus Mutans ◽  
Rational Design ◽  
Tooth Enamel ◽  
Gene Expression Pattern ◽  
Cell Communication ◽  
Mutans Streptococci ◽  
Communication Behaviors ◽  
Peptide Signaling ◽  
Highly Active

Abstract The formation of dental caries is a complex process that ultimately leads to damage of the tooth enamel from acids produced by microbes in attached biofilms. The bacterial interactions occurring within these biofilms between cariogenic bacteria, such as the mutans streptococci, and health-associated commensal streptococci, are thought to be critical determinants of health and disease. To better understand these interactions, a Streptococcus mutans reporter strain that actively monitors cell–cell communication via peptide signaling was cocultured with different commensal streptococci. Signaling by S. mutans, normally highly active in monoculture, was completely inhibited by several species of commensals, but only when the bacteria were in direct contact with S. mutans. We identified a novel gene expression pattern that occurred in S. mutans when cultured directly with these commensals. Finally, mutant derivatives of commensals lacking previously shown antagonistic gene products displayed wild-type levels of signal inhibition in cocultures. Collectively, these results reveal a novel pathway(s) in multiple health-associated commensal streptococci that blocks peptide signaling and induces a common contact-dependent pattern of differential gene expression in S. mutans. Understanding the molecular basis for this inhibition will assist in the rational design of new risk assessments, diagnostics, and treatments for the most pervasive oral infectious diseases.

scholarly journals Improvement in Thermostability of an Achaetomium sp. Strain Xz8 Endopolygalacturonase via the Optimization of Charge-Charge Interactions

2015 ◽  
Vol 81 (19) ◽  
pp. 6938-6944 ◽  
Author(s):  
Tao Tu ◽  
Huiying Luo ◽  
Kun Meng ◽  
Yanli Cheng ◽  
Rui Ma ◽  
...  
Keyword(s):  
Rational Design ◽  
Residual Activity ◽  
Maximal Activity ◽  
Wild Type ◽  
Content Type ◽  
Highly Active ◽  
Wide Ph Range ◽  
Enzyme Thermal Stability ◽  
Ph Range ◽  
Charge Interactions

ABSTRACTImproving enzyme thermostability is of importance for widening the spectrum of application of enzymes. In this study, a structure-based rational design approach was used to improve the thermostability of a highly active, wide-pH-range-adaptable, and stable endopolygalacturonase (PG8fn) fromAchaetomiumsp. strain Xz8 via the optimization of charge-charge interactions. By using the enzyme thermal stability system (ETSS), two residues—D244 and D299—were inferred to be crucial contributors to thermostability. Single (D244A and D299R) and double (D244A/D299R) mutants were then generated and compared with the wild type. All mutants showed improved thermal properties, in the order D244A < D299R < D244A/D299R. In comparison with PG8fn, D244A/D299R showed the most pronounced shifts in temperature of maximum enzymatic activity (Tmax), temperature at which 50% of the maximal activity of an enzyme is retained (T50), and melting temperature (Tm), of about 10, 17, and 10.2°C upward, respectively, with the half-life (t1/2) extended by 8.4 h at 50°C and 45 min at 55°C. Another distinguishing characteristic of the D244A/D299R mutant was its catalytic activity, which was comparable to that of the wild type (23,000 ± 130 U/mg versus 28,000 ± 293 U/mg); on the other hand, it showed more residual activity (8,400 ± 83 U/mg versus 1,400 ± 57 U/mg) after the feed pelleting process (80°C and 30 min). Molecular dynamics (MD) simulation studies indicated that mutations at sites D244 and D299 lowered the overall root mean square deviation (RMSD) and consequently increased the protein rigidity. This study reveals the importance of charge-charge interactions in protein conformation and provides a viable strategy for enhancing protein stability.

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