TERRACE INDUCED HOMOCHIRAL SELF-ASSEMBLY OF ZINC PHTHALOCYANINEON COPPER (111) SURFACE

2016 ◽  
Vol 23 (06) ◽  
pp. 1650047
Author(s):  
XIN SONG ◽  
HUIHUI KONG ◽  
LACHENG LIU ◽  
XIAOQING LIU ◽  
MINGDONG DONG ◽  
...  
Keyword(s):  
Self Assembly ◽  
Growth Process ◽  
Room Temperature ◽  
Organic Molecules ◽  
The Self ◽  
Step Edge ◽  
Suitable Method ◽  
Large Area ◽  
Molecular Assemblies ◽  
Lower Terrace

It is still a challenge to find a suitable method to fabricate a well-defined homochiral surface from achiral molecules, and one of the possible methods is to modify surfaces with organic molecular assemblies. Large-area chiral self-assembly nanostructures have been observed at room temperature by depositing ZnPc molecules on a Cu(111) surface. The growth process has been investigated. ZnPc molecules get adsorbed first at the terrace steps, and then extend over the lower terrace until the whole terrace is covered with ZnPc molecules; such growth process would be stopped when the self-assembly nanostructure run into a decorated upper terrace step edge. We found that the terrace steps with specific directions with respect to the close-packed directions of the substrate can induce homochiral self-assembly on the lower terraces. So we can propose a possible way to fabricate a well-defined homochiral surface from achiral organic molecules.

Electron Microscopy Study of Submicron Size Antiferromagnetic KMnF3 Nanoparticles and Their Self-assembly

2003 ◽  
Vol 775 ◽  
Author(s):  
Jeffrey Anderson ◽  
Rubi Garcia ◽  
Weilie L. Zhou
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Submicron Particles ◽  
Spherical Particles ◽  
Large Area ◽  
Homogeneous Crystal ◽  
Field Emission Electron Microscopy

AbstractSubmicron KMnF3 cubic and spherical nanoparticles were synthesized using the reverse micelle method. The nanostructures of the nanocrystals were studied by field emission electron microscopy and transmission electron microscopy. KMnF3 nanocrystals synthesized at room temperature started with cubic submicron particles (∼100 nm) and consisted of KMnF3 nanocrystallites (10-15 nm). As the reaction continued, the nanocrystals fused together and transformed into perfect cubic nanocrystals. Spherical beads composed of KMnF3 nanocrystallites were observed at low temperature synthesis. As the reaction continued, the spherical particles grew larger, however, no characteristic cubic shape of KMnF3 nanoparticles were observed. Even as they grew larger, there was no evidence of homogeneous crystal morphology as seen in the room temperature samples. Cubic shape KMnF3 nanocrystals were self-assembled into large area self-assembling patterns.

Hydrothermal Syntheses, Crystal Structures, and Luminescent Properties of Two MnII Coordination Polymers: From Two-Fold Interpenetrated pcu Topological Net to Polycatenated 2D+2D→3D Framework

2015 ◽  
Vol 68 (2) ◽  
pp. 322 ◽  
Author(s):  
Wenlong Liu ◽  
Mengqiang Wu ◽  
Xueying Wang ◽  
Wei Wang ◽  
Dayu Liu ◽  
...  
Keyword(s):  
Dicarboxylic Acid ◽  
Coordination Polymers ◽  
Self Assembly ◽  
Room Temperature ◽  
Luminescent Properties ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
3D Framework ◽  
Dimethyl Benzene

Using a hydrothermal synthesis, the self-assembly of MnII ions and 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene with two dicarboxylate ligands, 2-nitrobenzene-1,4-dicarboxylic acid (2-H2ata) and 5-methylbenzene-1,3-dicarboxylic acid (5-CH3-H2ip) constructed two interesting coordination polymers: [Mn(2-ata)(bimb)]n (1) and {[Mn(5-CH3-ip)(bimb)1.5]·2H2O}n (2), where bimb refers to 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene. Their structures were determined by single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy. Complex 1 exhibits a 2-fold interpenetrated pcu net. Complex 2 shows an unusual polycatenated 2D+2D→3D framework. In addition, the solid-state photoluminescent properties of 1 and 2 were investigated at room temperature.

scholarly journals Fabrication of C60Fullerene Nanofibers by Volatile Diffusion Method

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Bingzhe Wang ◽  
Xin Gao ◽  
Guangzhe Piao
Keyword(s):  
Crystal Growth ◽  
Self Assembly ◽  
Growth Process ◽  
Room Temperature ◽  
Isopropyl Alcohol ◽  
Diffusion Method ◽  
Short Fibers ◽  
Aspect Ratios ◽  
Crystal Growth Process ◽  
First Time

C60fullerene nanofibers (FNFs) were for the first time prepared by a volatile diffusion method using toluene as solvent and isopropyl alcohol as precipitation agent in room temperature, 25°C. FNFs with different lengths, aspect ratios, and morphologies could be fabricated by changing incubation time. Meanwhile, as for a crystal growth process, a possible mechanism of the formation of the crystal of FNFs was proposed in which the short and thin FNFs are the result of crystal growth, and self-assembly happens between the short fibers and thus leads to the formation of thick and long bundles of the FNFs.

How Did It All Begin?: The Self-Assembly of Organic Molecules and the Origin of Cellular Life

2002 ◽  
Vol 11 ◽  
pp. 179-194
Author(s):  
David W. Deamer
Keyword(s):  
Origin Of Life ◽  
20Th Century ◽  
Self Assembly ◽  
Organic Molecules ◽  
Western Culture ◽  
The Self ◽  
Late 20Th Century ◽  
Cellular Life ◽  
The Earth ◽  
The Origin Of Life

Movies are the myths of late-20th century western culture. Because of the power of films likeETto capture our imagination, we are more likely than past generations to accept the possibility that life exists elsewhere in our galaxy. Such a myth can be used to sketch the main themes of this chapter, which concern the origin of life on the Earth.

Bis-naphthalimides bridged by electron acceptors: optical and self-assembly characteristics

RSC Advances ◽  
2016 ◽  
Vol 6 (75) ◽  
pp. 71638-71651 ◽  
Author(s):  
Ankita Saini ◽  
K. R. Justin Thomas
Keyword(s):  
Self Assembly ◽  
Organic Molecules ◽  
Vital Role ◽  
Electron Acceptors ◽  
Supramolecular Structures ◽  
The Self ◽  
Small Organic Molecules

The self-assembly of small organic molecules into molecular stacks plays a vital role in the construction of stable supramolecular structures.

scholarly journals Adjacent functional group effects on the assembly of columnar liquid crystals

2020 ◽  
Vol 98 (7) ◽  
pp. 379-385
Author(s):  
Carson O. Zellman ◽  
Danielle Vu ◽  
Vance E. Williams
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Self Assembly ◽  
Room Temperature ◽  
Functional Group ◽  
The Self ◽  
Clearing Temperature ◽  
Crystal Phases ◽  
Potential Strategy ◽  
The Impact

Although the impact of individual functional groups on the self-assembly of columnar liquid crystal phases has been widely studied, the effect of varying multiple substituents has received much less attention. Herein, we report a series of dibenzo[a,c]phenazines containing an alcohol or ether adjacent to an electron-withdrawing ester or acid. With one exception, these difunctional mesogens form columnar phases. The phase behavior appeared to be dominated by the electron-withdrawing substituent; transition temperatures were similar to derivatives with these groups in isolation. In most instances, the addition of an electron-donating group ortho to an ester or acid suppressed the melting temperature and elevated the clearing temperature, leading to broader liquid crystal thermal ranges. This effect was more pronounced for derivatives functionalized with longer chain hexyloxy groups. These results suggest a potential strategy for controlling the phase ranges of columnar liquid crystals and achieving room temperature mesophases.

Self-assembly study of ammonium oleanolate and generation of gel– gold nanoparticle hybrid material

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Braja Gopal Bag ◽  
Subhajit Das
Keyword(s):  
Hybrid Material ◽  
Self Assembly ◽  
Room Temperature ◽  
Aqueous Ammonia ◽  
The Self ◽  
Solvent Mixtures ◽  
Optical Birefringence ◽  
Aqueous Solvent Mixtures ◽  
Aqueous Solvent ◽  
The Stability

A solution of oleanolic acid, a renewable nano-sized monohydroxy triterpenic acid in tetrahydrofuran, transformed into a gel instantly at room temperature on treatment with aqueous ammonia. Study of the self-assembly properties of ammonium oleanolate in water and aqueous solvent mixtures indicated that it self-assembles in the aqueous solvent mixtures forming gels in DMSO-water and DMF-water. Fibrillar networks with optical birefringence properties were observed by polarized optical microscopy. Scanning electron microscopy of the dried gel samples indicated fibrillar networks with fibers of nano to micrometer diameters. The thermodynamic parameters calculated from the gel to sol transition temperatures indicated the stability of the gels. A gel-gold nanoparticles hybrid material has also been prepared and characterized by HRTEM, EDX, SAED and surface Plasmon resonance studies.

Organic chemistry under hydrothermal conditions

2012 ◽  
Vol 85 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Sabine Avola ◽  
Marie Guillot ◽  
Denilson da Silva-Perez ◽  
Stephane Pellet-Rostaing ◽  
Werner Kunz ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Room Temperature ◽  
Organic Molecules ◽  
The Self ◽  
Organic Reactions ◽  
Superheated Water ◽  
Hydrothermal Conditions ◽  
Daily Experience ◽  
Catalyzed Reactions ◽  
Temperature Water

At elevated temperature, several properties of water are strongly altered compared to what our daily experience tells us: the dielectric constant of water, for example, is reduced, so that water can more easily solubilize organic molecules. In addition, the self-dissociation constant of water is increased (by three orders of magnitude at 250 °C), thus favoring H+- and OH–-catalyzed reactions. Surprisingly, while room-temperature water and supercritical water (SCW) are well known for promoting organic reactions, the middle temperature range still remains largely unexplored. Therefore, this contribution aims at giving an overview of organic reactions that may be promoted by superheated water.

Porphyrin self-assembly as template for RNA?

2001 ◽  
Vol 05 (09) ◽  
pp. 691-701 ◽  
Author(s):  
GERLINDE BISCHOFF ◽  
ROBERT BISCHOFF ◽  
SIEGFRIED HOFFMANN
Keyword(s):  
Self Assembly ◽  
Electrostatic Interactions ◽  
Room Temperature ◽  
Helical Structure ◽  
Scanning Force Microscopy ◽  
The Self ◽  
Scanning Calorimetry ◽  
Low Salt ◽  
Aqueous Conditions ◽  
Increasing Temperature

The self-assembly of chiral porphyrin molecules HpD (hematoporphyrin IX derivative) has been shown to form helical fibers in low salt aqueous conditions. The spectroscopic (UV and circular dichroism (CD)), thermodynamic (Tm, differential scanning calorimetry (DSC)) and microscopic (light and scanning force microscopy (SFM)) examinations of the HpD properties were performed individually and in the presence of nucleic acid double strands (15–60 °C, 0–50 mM NaCl ). The asymmetric HpD molecules themselves at room temperature show sharp positive or negative CD signals, which increase enormously with HpD concentration. The data show strong evidence for the external self-stacking interaction of HpD , pure and in the presence of polynucleotides. At low salt concentration (<40 mM NaCl , pH 7) the spectra change completely by increasing the temperature. At 35 to 40 °C RNA-similar spectra of the pure HpD self-assemblies (without nucleic acids) occur. At higher temperatures the aggregates become unstable and break off. At room temperature the helical structure of the fibers could be visualized by SFM investigations. Molecular modeling analysis offers dynamic arrangements of the self-assemblies from stacks to spiral-like superstructures with increasing temperature. Hydrogen bonding, electron transferring and electrostatic interactions determine the shape of the proposed highly flexible arrangements. Moreover, the interrelation between the HpD stacks and the helix of the polynucleotides was studied. The calculated low transition energies indicate the importance of these structures as a crossing link. All data are discussed in favor of a hypothetical evolutionary matrix role in porphyrin self-assembly for RNA.

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