A New Synergic-Assembly Strategy Towards Three-Dimensional (3D) Hollow Nanoarchitectures

2008 ◽  
Vol 8 (12) ◽  
pp. 6208-6222 ◽  
Author(s):  
Changzheng Wu ◽  
Yi Xie
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Building Blocks ◽  
Growth Direction ◽  
The Self ◽  
Assembly Process ◽  
Next Generation ◽  
One Pot ◽  
Assembly Strategy

Large-scale synthesis and assembly of meso-, micro- and nanostructured building blocks with the desired orientations are of great interest for the next-generation nanoarchitecture design. On the consideration that the traditional synthetic methodologies for nanostructures often produce tangled nanounits, how to align the nanounits into the ordered orientation at high production yield is a great challenge to current methods. The present review describes a facile and controllable way to grow and assemble the 3D hollow nanoarchitectures, with the utilization of the synergic effects of hollowing process from the self-produced templates and the highly anisotropic growth of nanounits of the target materials in one-pot reaction. In this process, the building block nanounits spontaneously in-situ form owing to their highly anisotropic internal structure, while the self-produced templates act as the supporter and growth-direction guidance for the in-situ formed nanounits. Therefore, the whole assembly process is simple, controllable and without the complicated manipulations. Herein, in the light of the different kinds of self-produced templates involved in the assembly process, recent developments based on the new synergic-assembly strategy are reviewed according to the classifications: (1) self-produced gas bubble template strategy; (2) self-produced homogeneous solid template strategy; (3) self-produced heterogeneous solid template strategy. Notably, the synergic-assembly methodology described in this review provides a newly essential way to construct and assemble nanoarchitectures facilely and controllably, and is also a crucial step for the next-generation of nanoarchitecture design in the near future. In conclusion, the challenges and prospects for the future are discussed.

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.

Controllable Synthesis of Cobalt Porphyrin Nanocrystals through Micelle Confinement Self-Assembly

MRS Advances ◽  
2020 ◽  
Vol 5 (42) ◽  
pp. 2147-2155
Author(s):  
Sudi Chen ◽  
Xitong Ren ◽  
Shufang Tian ◽  
Jiajie Sun ◽  
Feng Bai
Keyword(s):  
Self Assembly ◽  
Water Oxidation ◽  
Separation Efficiency ◽  
Noncovalent Interactions ◽  
Building Blocks ◽  
The Self ◽  
Hexagonal Prism ◽  
Assembly Process ◽  
Surfactant Micelles ◽  
Cobalt Porphyrin

AbstractThe self-assembly of optically active building blocks into functional nanocrystals as high-activity photocatalysts is a key in the field of photocatalysis. Cobalt porphyrin with abundant catalytic properties is extensively studied in photocatalytic water oxidation and CO2 reduction. Here, we present the fabrication of cobalt porphyrin nanocrystals through a surfactant-assisted interfacial self-assembly process using Co-tetra(4-pyridyl) porphyrin as building block. The self-assembly process relies on the combined noncovalent interactions such as π-π stacking and axial Co-N coordination between individual porphyrin molecules within surfactant micelles. Tuning different reaction conditions (temperature, the ratio of co-solvent DMF) and types of surfactant, various nanocrystals with well-defined 1D to 3D morphologies such as nanowires, nanorods and nano hexagonal prism were obtained. Due to the ordered accumulation of molecules, the nanocrystals exhibit the properties of the enhanced capability of visible light capture and can conduce to improve the transport and separation efficiency of the photogenerated carriers, which is important for photocatalysis. Further studies of photocatalytic CO2 reduction are being performed to address the relationship between the size and shape of the nanocrystals with the photocatalytic activity.

Symmetrical tetra-β″-sulfoleno-meso-aryl-porphyrins — synthesis, spectroscopy and structural characterization

2014 ◽  
Vol 18 (01n02) ◽  
pp. 115-122 ◽  
Author(s):  
Srinivas Banala ◽  
Klaus Wurst ◽  
Bernhard Kräutler
Keyword(s):  
Metal Complexes ◽  
Crystal Structures ◽  
Structural Characterization ◽  
Building Blocks ◽  
Cycloaddition Reactions ◽  
One Pot

We report here the preparation (in "one-pot") of a tetra-β″-sulfoleno-meso-aryl-porphyrin in about 80% yield by using an optimized modification of Lindsey's variant of the Adler–Longo approach. The Zn ( II )-, Cu ( II )- and Ni ( II )-complexes of the symmetrical porphyrin were prepared and characterized spectroscopically. Crystal structures of the fluorescent Zn ( II )- and of the non-fluorescent Ni ( II )-tetra-β″-sulfoleno-meso-aryl-porphyrinates showed the highly substituted porphyrin ligands to be nearly perfectly planar. The Zn ( II )-complex of this porphyrin has been used as a thermal precursor of a reactive diene, and — formally — of lateral and diagonal bis-dienes, of a tris-diene and of a tetra-diene, which all underwent [4 + 2]-cycloaddition reactions in situ with a range of dienophiles. Thus, the tetra-β″-sulfoleno-meso-aryl-porphyrin and its metal complexes represent reactive building blocks, "programmed" for the syntheses of symmetrical and highly functionalized porphyrins.

scholarly journals Modification of a Single Atom Affects the Physical Properties of Double Fluorinated Fmoc-Phe Derivatives

2021 ◽  
Vol 22 (17) ◽  
pp. 9634
Author(s):  
Moran Aviv ◽  
Dana Cohen-Gerassi ◽  
Asuka A. Orr ◽  
Rajkumar Misra ◽  
Zohar A. Arnon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physical Properties ◽  
Self Assembly ◽  
Deep Understanding ◽  
Building Blocks ◽  
The Self ◽  
Single Atom ◽  
Supramolecular Organization ◽  
Assembly Process ◽  
Wide Range

Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.

One-pot three-component polymerization for in situ generation of AIE-active poly(tetraarylethene)s using Grignard reagents as building blocks

2020 ◽  
Vol 11 (35) ◽  
pp. 5601-5609
Author(s):  
Zijie Qiu ◽  
Qingqing Gao ◽  
Ting Han ◽  
Xiaolin Liu ◽  
Jacky W. Y. Lam ◽  
...  
Keyword(s):  
Building Blocks ◽  
Grignard Reagents ◽  
One Pot ◽  
Aggregation Induced Emission ◽  
In Situ Generation

A facile polymerization route for in situ generation of polymers with aggregation-induced emission (AIE) characteristics has been developed.

Design and chance in the self-assembly of macromolecules

2007 ◽  
Vol 35 (3) ◽  
pp. 502-507 ◽  
Author(s):  
J.A.R. Worrall ◽  
M. Górna ◽  
X.Y. Pei ◽  
D.R. Spring ◽  
R.L. Nicholson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Self Assembly ◽  
Synthetic Detergent ◽  
Stable Equilibrium ◽  
Three Dimensional ◽  
The Self ◽  
Biological Molecules ◽  
Assembly Process ◽  
Naturally Occurring ◽  
Polymeric Assemblies

The principles of self-assembly are described for naturally occurring macromolecules and for complex assemblies formed from simple synthetic constituents. Many biological molecules owe their function and specificity to their three-dimensional folds, and, in many cases, these folds are specified entirely by the sequence of the constituent amino acids or nucleic acids, and without the requirement for additional machinery to guide the formation of the structure. Thus sequence may often be sufficient to guide the assembly process, starting from denatured components having little or no folds, to the completion state with the stable, equilibrium fold that encompasses functional activity. Self-assembly of homopolymeric structures does not necessarily preserve symmetry, and some polymeric assemblies are organized so that their chemically identical subunits pack stably in geometrically non-equivalent ways. Self-assembly can also involve scaffolds that lack structure, as seen in the multi-enzyme assembly, the degradosome. The stable self-assembly of lipids into dynamic membraneous sheets is also described, and an example is shown in which a synthetic detergent can assemble into membrane layers.

The MLT distribution and detailed structure of ring current:  MMS observations

2021 ◽  
Author(s):  
Xin Tan ◽  
Malcolm Dunlop ◽  
Xiangcheng Dong ◽  
Yanyan Yang ◽  
Christopher Russell
Keyword(s):  
Current Density ◽  
Large Scale ◽  
Ring Current ◽  
Current System ◽  
Radial Profile ◽  
Three Dimensional ◽  
Current Density Distribution ◽  
Magnetic Storms ◽  
In Situ Data

<p>The ring current is an important part of the large-scale magnetosphere-ionosphere current system; mainly concentrated in the equatorial plane, between 2-7 R<sub>E</sub>, and strongly ordered between ± 30 ° latitude. The morphology of ring current directly affects the geomagnetic field at low to middle latitudes. Rapid changes in ring current densities can occur during magnetic storms/sub-storms. Traditionally, the Dst index is used to characterize the intensity of magnetic storms and to reflect the variation of ring current intensity, but this index does not reflect the MLT distribution of ring current. In fact, the ring current has significant variations with MLT, depending on geomagnetic activity, due to the influence of multiple factors; such as, the partial ring current, region 1/region 2 field-aligned currents, the magnetopause current and sub-storm cycle (magnetotail current). The form of the ring current has been inferred from the three-dimensional distribution of ion differential fluxes from neutral atom imaging; however, this technique can not directly obtain the current density distribution (as can be obtained using multi-spacecraft in situ data). Previous in situ estimates of current density have used: Cluster, THEMIS and other spacecraft groups to study the distribution of the ring current for limited ranges of either radial profile, or MLT and MLAT variations. Here, we report on an extension to these studies using FGM data from MMS obtained during the period September 1, 2015 to December 31, 2016, when the MMS orbit and configuration provided good coverage. We employ the curlometer method to calculate the current density, statistically, to analysis the MLT distribution according to different geomagnetic conditions. Our results show the clear asymmetry of the ring current and its different characteristics under different geomagnetic conditions.</p>

Sonochemical synthesis of large-scale single-crystal PbS nanorods

2003 ◽  
Vol 18 (5) ◽  
pp. 1188-1191 ◽  
Author(s):  
S. M. Zhou ◽  
Y. S. Feng ◽  
L. D. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Large Scale ◽  
Three Dimensional ◽  
Ultrasound Irradiation ◽  
Building Blocks ◽  
Uniform Structure ◽  
X Ray ◽  
Transmission Electron

Large-scale single-crystal cubic PbS nanorods were successfully achieved by using ultrasound irradiation in certain ethylenediamine tetraacetic acid (EDTA) solutions, particularly in the solution of Pb:EDTA = 1:1. The obtained PbS nanorods were characterized using x-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersed x-ray spectrometry, selected area electronic diffraction, and high-resolution transmission electron microscopy. The results reveal that the PbS nanorods with straight and uniform structure have a diameter of about 70–80 nm and length of about 1000 nm, where the growth mechanism is tentatively discussed. The successful synthesis of these cubic structure semiconductor PbS nanorods may open up new possibilities for using these materials as building blocks to create functional two-dimensional or three-dimensional nanostructured materials.

Soluble salt self-assembly-assisted synthesis of three-dimensional hierarchical porous carbon networks for supercapacitors

2015 ◽  
Vol 3 (44) ◽  
pp. 22266-22273 ◽  
Author(s):  
Shan Zhu ◽  
Jiajun Li ◽  
Chunnian He ◽  
Naiqin Zhao ◽  
Enzuo Liu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Water Soluble ◽  
The Self ◽  
Soluble Salts ◽  
Hierarchical Porous Carbon ◽  
One Pot ◽  
Hierarchical Porous ◽  
Hierarchical Porous Carbons ◽  
Carbon Networks

Three-dimensional hierarchical porous carbons are synthesized via a simple one-pot method using the self-assembly of various water-soluble salts as structure-directing templates, which exhibit excellent capacitive performance.

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