scholarly journals Mechanistic Insight into the Precursor Chemistry of ZrO2 and HfO2 Nanocrystals; towards Size-Tunable Syntheses

2021 ◽  
Author(s):  
Rohan Pokratath ◽  
Dietger Van den Eynden ◽  
Susan Rudd Cooper ◽  
Jette Katja Mathiesen ◽  
Valérie Waser ◽  
...  
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Gain Control ◽  
Complex Oxide ◽  
Precursor Chemistry ◽  
Lewis Base ◽  
Reaction Yield ◽  
Resonance Spectroscopy ◽  
Mechanistic Insight ◽  
Insight Into

One can nowadays readily generate monodisperse colloidal nanocrystals, but a retrosynthetic analysis is still not possible since the underlying chemistry is often poorly understood. Here, we provide insight into the reaction mechanism of colloidal zirconia and hafnia nanocrystals synthesized from metal chloride and metal isopropoxide. We identify the active precursor species in the reaction mixture through a combination of nuclear magnetic resonance spectroscopy (NMR), density functional theory (DFT) calculations, and pair distribution function (PDF) analysis. We gain insight into the interaction of the surfactant, tri-n-octylphosphine oxide (TOPO), and the different precursors. Interestingly, we identify a peculiar X-type ligand redistribution mechanism that can be steered by the relative amount of Lewis base (L-type). We further monitor how the reaction mixture decomposes using solution NMR and gas chromatography, and we find that ZrCl4 is formed as a by-product of the reaction, limiting the reaction yield. The reaction proceeds via two competing mechanisms: E1 elimination (dominating) and SN1 substitution (minor). Using this new mechanistic insight, we adapted the synthesis to optimize the yield and gain control over nanocrystal size. These insights will allow the rational design and synthesis of complex oxide nanocrystals.

Mechanistic Insight into Construction of Axially Chiral Biaryls via Palladium/Chiral Norbornene Cooperative Catalysis: a DFT-Based Computational Study

2021 ◽  
Author(s):  
Xuexiang Ma ◽  
Aili Feng ◽  
Chengbu Liu ◽  
Dongju Zhang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Cooperative Catalysis ◽  
Mechanistic Insight ◽  
Aryl Bromides ◽  
Axially Chiral ◽  
Insight Into

Density functional theory calculations were performed on a prototype of three-component reactions involving aryl iodides, 2,6-substituted aryl bromides, and acrylates to understand the construction of axially chiral biaryls through the...

scholarly journals Designing multivalent probes for tunable superselective targeting

2015 ◽  
Vol 112 (18) ◽  
pp. 5579-5584 ◽  
Author(s):  
Galina V. Dubacheva ◽  
Tine Curk ◽  
Rachel Auzély-Velty ◽  
Daan Frenkel ◽  
Ralf P. Richter
Keyword(s):  
Binding Sites ◽  
Rational Design ◽  
Cell Surface Receptor ◽  
Molecular Characteristics ◽  
Surface Binding ◽  
Binding Properties ◽  
Practical Applications ◽  
Mechanistic Insight ◽  
Surface Receptor ◽  
Insight Into

Specific targeting is common in biology and is a key challenge in nanomedicine. It was recently demonstrated that multivalent probes can selectively target surfaces with a defined density of surface binding sites. Here we show, using a combination of experiments and simulations on multivalent polymers, that such “superselective” binding can be tuned through the design of the multivalent probe, to target a desired density of binding sites. We develop an analytical model that provides simple yet quantitative predictions to tune the polymer’s superselective binding properties by its molecular characteristics such as size, valency, and affinity. This work opens up a route toward the rational design of multivalent probes with defined superselective targeting properties for practical applications, and provides mechanistic insight into the regulation of multivalent interactions in biology. To illustrate this, we show how the superselective targeting of the extracellular matrix polysaccharide hyaluronan to its main cell surface receptor CD44 is controlled by the affinity of individual CD44–hyaluronan interactions.

Mechanistic Insight into H2S Adsorption and Dissociation on MoP(010): A Density Functional Investigation

2017 ◽  
Vol 1142 ◽  
pp. 300-305
Author(s):  
Gui Xia Li ◽  
Hou Yu Zhu ◽  
Lian Ming Zhao ◽  
Wen Yue Guo ◽  
Xiao Qing Lu ◽  
...  
Keyword(s):  
Density Functional ◽  
Co Adsorption ◽  
Adsorbed Species ◽  
Functional Theory ◽  
Mechanistic Insight ◽  
Structure Sensitive ◽  
Bond Scission ◽  
Functional Investigation ◽  
Adsorption And Dissociation ◽  
Insight Into

H2S adsorption and dissociation on MoP(010) were investigated using density functional theory (DFT) together with periodic slab models. Several different possibilities for H2S, SH, S and H adsorption were considered. Our results show that the H2S, SH and H prefer to adsorb at bridge site, while S adsorbs preferentially at hcp and bridge sites. Additionally, the optimum co-adsorption configurations for SH/H and S/H were determined. The results indicate that the co-adsorbed species repel each other slightly on MoP(010) surface. Finally, the potential energy profile of H2S dissociation on MoP(010) surface was given out. The dissociation energy barriers of the S–H bond scission exhibit that H2S prefers to dissociate on MoP(010) surface. When compared with MoP(001) surface, the obvious differences in H2S decomposition arise demonstrate that the MoP-based catalysts are structure-sensitive.

Kinetic and mechanistic insight into Lewis base and acid-mediated phenylselenoetherification of 2,6-dimethyl-hept-5-en-2-ol

2015 ◽  
Vol 26 (4) ◽  
pp. 915-922 ◽  
Author(s):  
Marina D. Kostić ◽  
Vera M. Divac ◽  
Ralph Puchta ◽  
Zorica M. Bugarčić
Keyword(s):  
Lewis Base ◽  
Mechanistic Insight ◽  
Insight Into

Mechanistic insight into Cu/Ag-cocatalyzed C–H activation of arenes with oxygen as the terminal oxidant

RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 35855-35858 ◽  
Author(s):  
Gui-Yu Ruan ◽  
Zheng-Hang Qi ◽  
Ye Zhang ◽  
Wei Liu ◽  
Yong Wang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition States ◽  
Functional Theory ◽  
Mechanistic Insight ◽  
Insight Into

The possible transition states of C–H activation on the dehydrogenate coupling of arenes with alcohols employing Ag(i) additives were investigated using B3LYP density functional theory.

Mechanistic insight into the aerobic oxidation of benzyl alcohol catalyzed by the CuII–TEMPO catalyst in alkaline water solution

RSC Advances ◽  
2015 ◽  
Vol 5 (102) ◽  
pp. 83976-83984 ◽  
Author(s):  
R. F. Duan ◽  
L. Cheng ◽  
Q. C. Zhang ◽  
L. S. Ma ◽  
H. Y. Ma ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Density Functional ◽  
Water Solution ◽  
Aerobic Oxidation ◽  
Density Functional Method ◽  
Alcohol Oxidation ◽  
Functional Method ◽  
Alkaline Water ◽  
Mechanistic Insight ◽  
Insight Into

The benzyl alcohol oxidation to benzaldehyde in the alkaline water solution catalyzed by CuII/L–TEMPO catalyst is investigated by density functional method. The favorable mechanisms and the role for the water ​have also been predicted.

DFT Studies Provide Mechanistic Insight into Nickel-Catalyzed Cross-Coupling Involving Organoaluminum-Mediated C–O Bond Cleavage

Synlett ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 2565-2568 ◽  
Author(s):  
Chao Wang ◽  
Masanobu Uchiyama ◽  
Ze-Kun Yang
Keyword(s):  
Density Functional ◽  
Reaction Pathway ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Lewis Acidity ◽  
Functional Theory ◽  
Mechanistic Insight ◽  
Insight Into ◽  
Strong Lewis Acidity

Density functional theory (DFT) calculations were performed to examine the reaction pathway of Ni-catalyzed cross-coupling with organoaluminum through C–O bond cleavage. The results indicate that the strong Lewis acidity of organoaluminums significantly facilitates the transmetalation step, but not the oxidative addition or reductive elimination step.

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