scholarly journals Carbon-boron clathrates as a new class of sp3-bonded framework materials

2020 ◽  
Vol 6 (2) ◽  
pp. eaay8361 ◽  
Author(s):  
Li Zhu ◽  
Gustav M. Borstad ◽  
Hanyu Liu ◽  
Piotr A. Guńka ◽  
Michael Guerette ◽  
...  
Keyword(s):  
Design Principle ◽  
Three Dimensional ◽  
Structure Type ◽  
Framework Materials ◽  
New Class ◽  
Tunable Properties ◽  
Chemical Design ◽  
Boron Substitution ◽  
Carbon Based

Carbon-based frameworks composed of sp3 bonding represent a class of extremely lightweight strong materials, but only diamond and a handful of other compounds exist despite numerous predictions. Thus, there remains a large gap between the number of plausible structures predicted and those synthesized. We used a chemical design principle based on boron substitution to predict and synthesize a three-dimensional carbon-boron framework in a host/guest clathrate structure. The clathrate, with composition 2Sr@B6C6, exhibits the cubic bipartite sodalite structure (type VII clathrate) composed of sp3-bonded truncated octahedral C12B12 host cages that trap Sr2+ guest cations. The clathrate not only maintains the robust nature of diamond-like sp3 bonding but also offers potential for a broad range of compounds with tunable properties through substitution of guest atoms within the cages.

Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22

2000 ◽  
Vol 626 ◽  
Author(s):  
Antje Mrotzek ◽  
Kyoung-Shin Choi ◽  
Duck-Young Chung ◽  
Melissa A. Lane ◽  
John R. Ireland ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystal ◽  
Thermoelectric Properties ◽  
Three Dimensional ◽  
Structure Type ◽  
Narrow Gap ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Metal Atoms ◽  
Anionic Framework

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.

A Peptoid with Extended Shape in Water

2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Biomolecular Recognition ◽  
Biological Application ◽  
New Class ◽  
Proteolytic Resistance ◽  
Pharmacokinetic Properties ◽  
Optically Pure ◽  
Three Dimensional Space

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>

A three-dimensional hierarchical Fe2O3@NiO core/shell nanorod array on carbon cloth: a new class of anode for high-performance lithium-ion batteries

Nanoscale ◽  
2013 ◽  
Vol 5 (17) ◽  
pp. 7906 ◽  
Author(s):  
Qin-qin Xiong ◽  
Jiang-ping Tu ◽  
Xin-hui Xia ◽  
Xu-yang Zhao ◽  
Chang-dong Gu ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
High Performance ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Nanorod Array ◽  
Core Shell ◽  
Carbon Cloth ◽  
New Class

Carbon-Based Sorbents with Three-Dimensional Architectures for Water Remediation

Small ◽  
2015 ◽  
Vol 11 (27) ◽  
pp. 3319-3336 ◽  
Author(s):  
Bo Chen ◽  
Qinglang Ma ◽  
Chaoliang Tan ◽  
Teik-Thye Lim ◽  
Ling Huang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Water Remediation ◽  
Carbon Based

A hydrostable and twofold interpenetrating three-dimensional zinc–organic framework with rob topology based on 4,4′-oxydibenzoate and 3,3′-dimethyl-4,4′-bipyridine ligands

2016 ◽  
Vol 72 (5) ◽  
pp. 373-378 ◽  
Author(s):  
Feng-Lan Liang ◽  
De-Yun Ma ◽  
Liang Qin
Keyword(s):  
Title Compound ◽  
Three Dimensional ◽  
New Class ◽  
Pyramidal Geometry ◽  
Potential Applications ◽  
Metal Organic ◽  
Ph Range ◽  
Square Pyramidal Geometry ◽  
Bright Blue Fluorescence ◽  
Bright Blue

Metal–organic frameworks (MOFs) are a new class of porous materials that have received widespread attention due to their potential applications in gas storage and/or separation, catalysis, luminescence, and so on. The title compound, poly[[(μ2-3,3′-dimethyl-4,4′-bipyridine-κ2N:N′)bis(μ4-4,4′-oxydibenzoato-κ4O:O′:O′′:O′′′)dizinc] tetrahydrate], {[Zn2(C14H8O5)2(C12H12N2)]·4H2O}n, has been prepared by the solvothermal assembly of Zn(NO3)2·6H2O, 4,4′-oxydi(benzoic acid) and 3,3′-dimethyl-4,4′-bipyridine. The two ZnIIatoms adopt the same five-coordinated distorted square-pyramidal geometry (i.e.ZnO4N), bonding to four O atoms from four different 4,4′-oxydibenzoate (oba) ligands and one N atom from a 3,3′-dimethyl-4,4′-bipyridine (dmbpy) ligand. The supramolecular secondary building unit (SBU) is a paddle-wheel [Zn2(COO)4] unit and these units are linked by oba ligands within the layer to form a two-dimensional net parallel to thebaxis, with the dmbpy ligands pointing alternately up and down, which is further extended by dmbpy ligands to form a three-dimensional framework withrobtopology. The single net leaves voids that are filled by mutual interpenetration of an independent equivalent framework in a twofold interpenetrating architecture. The title compound shows thermal stability up to 673 K and is stable in aqueous solutions in the pH range 5–9. Excitation and luminescence data observed at room temperature show that it emits a bright-blue fluorescence.

scholarly journals A Note on the Properties of Generalised Separable Spatial Autoregressive Process

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Mahendran Shitan ◽  
Shelton Peiris
Keyword(s):  
Three Dimensional ◽  
Real Data ◽  
Autoregressive Process ◽  
Spatial Modelling ◽  
Spectral Density Function ◽  
Data Sets ◽  
Additional Parameter ◽  
New Class ◽  
Spatial Autoregressive ◽  
Modelling And Forecasting

Spatial modelling has its applications in many fields like geology, agriculture, meteorology, geography, and so forth. In time series a class of models known as Generalised Autoregressive (GAR) has been introduced by Peiris (2003) that includes an index parameterδ. It has been shown that the inclusion of this additional parameter aids in modelling and forecasting many real data sets. This paper studies the properties of a new class of spatial autoregressive process of order 1 with an index. We will call this aGeneralised Separable Spatial Autoregressive(GENSSAR) Model. The spectral density function (SDF), the autocovariance function (ACVF), and the autocorrelation function (ACF) are derived. The theoretical ACF and SDF plots are presented as three-dimensional figures.

A NEW CHAOTIC SYSTEM AND BEYOND: THE GENERALIZED LORENZ-LIKE SYSTEM

2004 ◽  
Vol 14 (05) ◽  
pp. 1507-1537 ◽  
Author(s):  
JINHU LÜ ◽  
GUANRONG CHEN ◽  
DAIZHAN CHENG
Keyword(s):  
Chaotic System ◽  
Chaotic Attractor ◽  
Three Dimensional ◽  
Chaotic Attractors ◽  
Compound Structure ◽  
Constant Input ◽  
New Class ◽  
Dynamical Behaviors ◽  
Generalized Lorenz System ◽  
New Chaotic System

This article introduces a new chaotic system of three-dimensional quadratic autonomous ordinary differential equations, which can display (i) two 1-scroll chaotic attractors simultaneously, with only three equilibria, and (ii) two 2-scroll chaotic attractors simultaneously, with five equilibria. Several issues such as some basic dynamical behaviors, routes to chaos, bifurcations, periodic windows, and the compound structure of the new chaotic system are then investigated, either analytically or numerically. Of particular interest is the fact that this chaotic system can generate a complex 4-scroll chaotic attractor or confine two attractors to a 2-scroll chaotic attractor under the control of a simple constant input. Furthermore, the concept of generalized Lorenz system is extended to a new class of generalized Lorenz-like systems in a canonical form. Finally, the important problems of classification and normal form of three-dimensional quadratic autonomous chaotic systems are formulated and discussed.

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