Plutonium and transplutonium element trioxides: molecular structures, chemical bonding, and isomers

2015 ◽  
Vol 17 (38) ◽  
pp. 24831-24836 ◽  
Author(s):  
Andréi Zaitsevskii
Keyword(s):  
Chemical Bonding ◽  
Molecular Structures ◽  
Transplutonium Element ◽  
The Stability

The stability of the An·3O (An = Pu through Cf) lowest-energy isomers should decrease in the series Pu(vi)O3 > Am(v)O3 ≈ Bk(v)O3 > Cm(iii)O(O2) > Cf(iii)O(O2).

scholarly journals Uranium(iv) cyclobutadienyl sandwich compounds: synthesis, structure and chemical bonding

2020 ◽  
Vol 56 (6) ◽  
pp. 944-947 ◽  
Author(s):  
Nikolaos Tsoureas ◽  
Akseli Mansikkamäki ◽  
Richard A. Layfield
Keyword(s):  
Chemical Bonding ◽  
Molecular Structures ◽  
Sandwich Complexes ◽  
Sandwich Complex ◽  
Sandwich Compounds ◽  
Bonding Properties ◽  
Half Sandwich

The synthesis, molecular structures and bonding properties of two uranium(iv) cyclobutadienyl half-sandwich complexes and a doubly activated cyclobutadienyl sandwich complex are described.

Carbon-13 studies of sulphur-terminated carbon chains: chemical bonding, molecular structures, and formation pathways

2021 ◽  
Author(s):  
Michael C. McCarthy ◽  
Kin Long Kelvin Lee ◽  
Jessica P. Porterfield ◽  
P. Bryan Changala ◽  
André K. Eckhardt
Keyword(s):  
Chemical Bonding ◽  
Molecular Structures ◽  
Carbon Chains

scholarly journals Hydrosilylation of Reactive Quantum Dots and Siloxanes for Stable Quantum Dot Films

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 905
Author(s):  
Changmin Lee ◽  
Eunhee Nam ◽  
Woosuk Lee ◽  
Heeyeop Chae
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Nucleophilic Addition ◽  
Addition Reaction ◽  
Light Emitting Diode ◽  
Molecular Structures ◽  
One Pot ◽  
Nucleophilic Addition Reaction ◽  
The Stability ◽  
Photo Stability

The reactive acrylate-terminated CdZnSeS/ZnS quantum dots (QDs) were designed and prepared by the effective synthetic route to bond with a siloxane matrix via hydrosilylation. The conventional QD with oleic acid ligands does not have any reactivity, so the QDs were functionalized to assign reactivity for the QDs by the ligand modification of two step reactions. The oleic acid of the QDs was exchanged for hydroxyl-terminated ligands as an intermediate product by one-pot reaction. The hydroxyl-terminated QDs and acrylate-containing isocyanates were combined by nucleophilic addition reaction with forming urethane bonds and terminal acrylate groups. No degradation in quantum yield was observed after ligand exchange, nor following the nucleophilic addition reaction. The modification reactions of ligands were quantitatively controlled and their molecular structures were precisely confirmed by FT-IR and 1H-NMR. The QDs with acrylate ligands were then reacted with hydride-terminated polydimethylsiloxane (H-PDMS) to form a QD-siloxane matrix by thermal curing via hydro-silylation for the first time. The covalent bonding between the QDs and the siloxane matrix led to improvements in the stability against oxygen and moisture. Stability at 85 °C and 85% relative humidity (RH) were both improved by 22% for the QD-connected siloxane QD films compared with the corresponding values for conventional QD-embedded poly(methylmethacrylate) (PMMA) films. The photo-stability of the QD film after 26 h under a blue light-emitting diode (LED) was also improved by 45% in comparison with those of conventional QD-embedded PMMA films.

Complex cubic metallides AM~6 (A=Ca, Sr; M=Zn, Cd, Hg). Synthesis, crystal chemistry and chemical bonding

2017 ◽  
Vol 232 (7-9) ◽  
Author(s):  
Michael Schwarz ◽  
Marco Wendorff ◽  
Caroline Röhr
Keyword(s):  
Crystal Chemistry ◽  
Chemical Bonding ◽  
Theoretical Study ◽  
The Stability ◽  
Stability Ranges

AbstractIn a systematic synthetic, crystallographic and bond theoretical study, the stability ranges as well as the distribution of the isoelectronic late

scholarly journals Effects of Doped Elements (Si, Cr, W and Nb) on the Stability, Mechanical Properties and Electronic Structures of MoAlB Phase by the First-Principles Calculation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4221
Author(s):  
Yongxin Jian ◽  
Zhifu Huang ◽  
Yu Wang ◽  
Jiandong Xing
Keyword(s):  
Mechanical Properties ◽  
Chemical Bonding ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Elemental Doping ◽  
The Stability ◽  
W Doping

First-principles calculations based on density functional theory (DFT) have been performed to explore the effects of Si, Cr, W, and Nb elements on the stability, mechanical properties, and electronic structures of MoAlB ternary boride. The five crystals, with the formulas of Mo4Al4B4, Mo4Al3SiB4, Mo3CrAl4B4, Mo3WAl4B4, and Mo3NbAl4B4, have been respectively established. All the calculated crystals are thermodynamically stable, according to the negative cohesive energy and formation enthalpy. By the calculation of elastic constants, the mechanical moduli and ductility evolutions of MoAlB with elemental doping can be further estimated, with the aid of B/G and Poisson’s ratios. Si and W doping cannot only enhance the Young’s modulus of MoAlB, but also improve the ductility to some degree. Simultaneously, the elastic moduli of MoAlB are supposed to become more isotropic after Si and W addition. However, Cr and Nb doping plays a negative role in ameliorating the mechanical properties. Through the analysis of electronic structures and chemical bonding, the evolutions of chemical bondings can be disclosed with the addition of dopant. The enhancement of B-B, Al/Si-B, and Al/Si-Mo bondings takes place after Si substitution, and W addition apparently intensifies the bonding with B and Al. In this case, the strengthening of chemical bonding after Si and W doping exactly accounts for the improvement of mechanical properties of MoAlB. Additionally, Si doping can also improve the Debye temperature and melting point of the MoAlB crystal. Overall, Si element is predicted to be the optimized dopant to ameliorate the mechanical properties of MoAlB.

scholarly journals Structure and Physical Properties of Cardamonin: A Spectroscopic and Computational Approach

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4070 ◽  
Author(s):  
Iwona Budziak ◽  
Marta Arczewska ◽  
Daniel M. Kamiński
Keyword(s):  
Crystal Structure ◽  
Crystal Lattice ◽  
Density Functional ◽  
Xrd Analysis ◽  
Biological Properties ◽  
Molecular Structures ◽  
Functional Theory ◽  
Water Fractions ◽  
The Stability ◽  
Single Crystal Xrd Analysis

This is the first study of the crystal structure of cardamonin (CA) confirmed using single-crystal XRD analysis. In the crystal lattice of CA, two symmetry independent molecules are linked by hydrogen bonds within the layers and by the π···π stacking interactions in the columns which lead to the occurrence of two types of conformations among the CA molecules in the crystal structure. To better understand the stability of these arrangements in both crystals and the gaseous phase, seven different CA dimers were theoretically calculated. The molecular structures were optimized using density functional theory (DFT) at the B3LYP/6–311G+(d,p) level and the spectroscopic results were compared. It was found that the calculated configurations of dimer I and III were almost identical to the ones found in the CA crystal lattice. The calculated UV-Vis spectra for the CA monomer and dimer I were perfectly consistent with the experimental spectroscopic data. Furthermore, enhanced emissions induced by aggregated CA molecules were registered in the aqueous solution with the increase of water fractions. The obtained results will help to further understand the relation between a variety of conformations and the biological properties of CA, and the results are also promising in terms of the applicability of CA as a bioimaging probe to monitor biological processes.

Characterization of HF Treated (100) Si Surfaces by Surface Charge Analysis (SCA)

1992 ◽  
Vol 259 ◽  
Author(s):  
Jon T. Fitch
Keyword(s):  
Electrical Properties ◽  
Surface Charge ◽  
Chemical Bonding ◽  
Oxide Thickness ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Charge Analysis ◽  
The Stability ◽  
Over Time

ABSTRACTSurface Charge Analysis (SCA), and ellipsometry have been used to study the stability over time of HF treated (100) silicon surfaces as a function of the post-HF rinse time. Using SCA, the electrical properties of the chemical terminating layer of these silicon surfaces were measured. The surfaces which remained native oxide free the longest (−10 hours) had very low Qox and Dit values on the order of 1.0 × 1011/cm2 and 5.0 × 1010 eV−lcm−2, respectively. A good correlation was found between Dit and the native oxide thickness measured by ellipsometry. This and other results are discussed in terms of the chemical bonding on the silicon surfaces.

The Isolation and Structural Analysis of Compound Emulsifier

2011 ◽  
Vol 317-319 ◽  
pp. 703-707
Author(s):  
Shan Shan Han ◽  
Jin Yun Xu ◽  
Guo Zheng ◽  
Hua Ying Liang ◽  
Yu Sun
Keyword(s):  
Fourier Transform ◽  
Structural Analysis ◽  
Silica Gel ◽  
1H Nmr ◽  
Fourier Transform Infrared ◽  
Molecular Structures ◽  
Oil Products ◽  
Mixed Solution ◽  
The Stability

Nowadays, the stability of the mixed solution usually is improved by adding appropriate amount of emulsifier needed in many oil products, in order to reach the better effect of solution mulsification. In this paper, using silica gel column seperation to isolate pure ingredient of the emulsifier component, and all molecular structures prepared on silica gel were characterized by Fourier transform infrared (FTIR) spectum and silid-state 1H NMR experimental observations.

scholarly journals Isotopic studies of trans- and cis-HOCO using rotational spectroscopy: Formation, chemical bonding, and molecular structures

2016 ◽  
Vol 144 (12) ◽  
pp. 124304 ◽  
Author(s):  
Michael C. McCarthy ◽  
Oscar Martinez ◽  
Brett A. McGuire ◽  
Kyle N. Crabtree ◽  
Marie-Aline Martin-Drumel ◽  
...  
Keyword(s):  
Chemical Bonding ◽  
Molecular Structures ◽  
Rotational Spectroscopy ◽  
Isotopic Studies

Abstract 286: Structural Determinants Of Thermodynamic Stability And Actin-binding Function Of Dystrophin And Utrophin

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Krishna Mallela ◽  
Swati Bandi ◽  
Surinder Singh
Keyword(s):  
Three Dimensional ◽  
Molecular Structures ◽  
Actin Binding ◽  
Protein Drug ◽  
Structural Determinants ◽  
Folding Rate ◽  
Incurable Disease ◽  
Binding Function ◽  
The Stability ◽  
And Function

Muscular dystrophy (MD) is an incurable disease, and affects all types of muscles. The decreased function of heart muscles causes heart problems such as cardiomyopathy and congestive heart failure. A deficiency in functional dystrophin protein in muscle cells triggers the onset of Duchenne MD and Becker MD. Utrophin is the closest homologue of dystrophin and is being tested as a protein drug to replace the loss of functional dystrophin in human patients. However, utrophin is less stable and binds to actin through a different mode of contact when compared with dystrophin. To optimize utrophin as the protein drug, we first need to understand how its molecular structure controls its stability and function. Utrophin and dystrophin bind to actin using tandem calponin-homology (CH) domains at their N-terminus. Individual CH domains of utrophin and dystrophin are very similar in amino acid sequence and their three dimensional structures. The major difference is in their relative orientation around the linker region that connects the two CH domains. To determine the role of the linker, we designed constructs with linkers switched between utrophin and dystrophin. Our results indicate that the tandem CH domain of utrophin with dystrophin linker (UDL) is more stable than that of utrophin but less stable than that of dystrophin. Similarly, tandem CH domain of dystrophin with utrophin linker (DUL) is less stable than that of dystrophin but more stable than that of utrophin. Kinetic folding and unfolding studies suggest that the linker predominantly affects the folding rate rather than the unfolding rate. In addition to stability and folding, the linker also controls protein aggregation. UDL is more prone to aggregation when compared with that of utrophin, whereas DUL is less prone to aggregation when compared with that of dystrophin. These results indicate that the linker plays a major role in controlling the stability and function of tandem CH domains, and further suggests that it is possible to engineer utrophin to behave precisely like dystrophin based on their molecular structures.

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