Well-defined alternative polymer semiconductor using large size regioregular building blocks as monomers: electrical and electrochemical properties

2018 ◽  
Vol 6 (21) ◽  
pp. 5662-5670 ◽  
Author(s):  
Bogyu Lim ◽  
Dang Xuan Long ◽  
Song-Yi Han ◽  
Yoon-Chae Nah ◽  
Yong-Young Noh
Keyword(s):  
Molecular Weight ◽  
Conjugated Polymers ◽  
Electrochemical Properties ◽  
Building Blocks ◽  
Synthetic Strategy ◽  
Large Size ◽  
Large Molecular Weight ◽  
Polymer Semiconductor

We report an effective synthetic strategy to achieve well-defined regioregular alternative conjugated polymers using large molecular weight regioregular monomers.

The External Shape of Human γ GI Immunoglobulin from Crystal Sections

1971 ◽  
Vol 29 ◽  
pp. 428-429
Author(s):  
L. W. Labaw
Keyword(s):  
Molecular Weight ◽  
Sodium Phosphate ◽  
Osmium Tetroxide ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Large Molecular Weight ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Crystallographic Axes

Crystals of a human γGl immunoglobulin have the external morphology of diamond shaped prisms. X-ray studies have shown them to be monoclinic, space group C2, with 2 molecules per unit cell. The unit cell dimensions are a = 194.1, b = 91.7, c = 51.6Å, 8 = 102°. The relatively large molecular weight of 151,000 and these unit cell dimensions made this a promising crystal to study in the EM.Crystals similar to those used in the x-ray studies were fixed at 5°C for three weeks in a solution of mother liquor containing 5 x 10-5M sodium phosphate, pH 7.0, and 0.03% glutaraldehyde. They were postfixed with 1% osmium tetroxide for 15 min. and embedded in Maraglas the usual way. Sections were cut perpendicular to the three crystallographic axes. Such a section cut with its plane perpendicular to the z direction is shown in Fig. 1.This projection of the crystal in the z direction shows periodicities in at least four different directions but these are only seen clearly by sighting obliquely along the micrograph.

Application of Nitrogen Heterocyclic Carbenes in Organocatalysis

2020 ◽  
Vol 09 ◽  
Author(s):  
Minita Ojha ◽  
R. K. Bansal
Keyword(s):  
Asymmetric Catalysis ◽  
Building Blocks ◽  
Structural Features ◽  
Heterocyclic Carbenes ◽  
Stetter Reaction ◽  
Metal Pollutants ◽  
Synthetic Strategy ◽  
Wide Range ◽  
Benzoin Condensation ◽  
Nitrogen Heterocyclic

Background: During the last two decades, horizon of research in the field of Nitrogen Heterocyclic Carbenes (NHC) has widened remarkably. NHCs have emerged as ubiquitous species having applications in a broad range of fields, including organocatalysis and organometallic chemistry. The NHC-induced non-asymmetric catalysis has turned out to be a really fruitful area of research in recent years. Methods: By manipulating structural features and selecting appropriate substituent groups, it has been possible to control the kinetic and thermodynamic stability of a wide range of NHCs, which can be tolerant to a variety of functional groups and can be used under mild conditions. NHCs are produced by different methods, such as deprotonation of Nalkylhetrocyclic salt, transmetallation, decarboxylation and electrochemical reduction. Results: The NHCs have been used successfully as catalysts for a wide range of reactions making a large number of building blocks and other useful compounds accessible. Some of these reactions are: benzoin condensation, Stetter reaction, Michael reaction, esterification, activation of esters, activation of isocyanides, polymerization, different cycloaddition reactions, isomerization, etc. The present review includes all these examples published during the last 10 years, i.e. from 2010 till date. Conclusion: The NHCs have emerged as versatile and powerful organocatalysts in synthetic organic chemistry. They provide the synthetic strategy which does not burden the environment with metal pollutants and thus fit in the Green Chemistry.

scholarly journals Synthesis and characterization of an electron-deficient conjugated polymer based on pyridine-flanked diketopyrrolopyrrole

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12995-13003
Author(s):  
Jialin Yang ◽  
Li Yang ◽  
Qianqian Chen ◽  
Keke Guo ◽  
Ji-Min Han
Keyword(s):  
Conjugated Polymers ◽  
Electrochemical Properties ◽  
Conjugated Polymer ◽  
Synthesis And Characterization

We report a pyridine-flanked diketopyrrolopyrrole monomer and all-acceptor conjugated polymers synthesized therefrom. Photophysical, thermal and electrochemical properties of the polymers have been determined.

scholarly journals Synthesis of π-Conjugated Polymers Containing Benzotriazole Units via Palladium-Catalyzed Direct C-H Cross-Coupling Polycondensation for OLEDs Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 254
Author(s):  
Dong Han ◽  
Jingwen Li ◽  
Qiang Zhang ◽  
Zewang He ◽  
Zhiwei Wu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Quantum Efficiency ◽  
Cross Coupling ◽  
Building Blocks ◽  
Gravimetric Analysis ◽  
19F Nmr Spectra ◽  
Light Emitting ◽  
Molecular Weights ◽  
Palladium Catalyzed ◽  
Red Luminescence

Four D-π-A conjugated polymers, namely P1–P4, which contain benzotriazole building blocks in their backbone as acceptor, are synthesized via palladium-catalyzed direct C-H cross-coupling polycondensation of 5,6-difluorobenzotriazole with different thiophene derivatives, including 3-octylthiophene, 2,2’-bithiophene, thieno[3,4-b][1,4]dioxine, and 4,4-dioctyl-4H-silolo-[3,2-b:4,5-b’]dithiophene as donor units, respectively. Taking the polymer P1 as an example, the chemical structure of the polymer is demonstrated by 1H and 19F NMR spectra. The optical, electrochemical, and thermal properties of these polymers are assessed by UV–vis absorption and fluorescence spectroscopy, cyclic voltammetry (CV), and thermal gravimetric analysis (TGA), respectively. DFT simulations of all polymers are also performed to understand their physicochemical properties. Furthermore, P1 and P2, which have relatively higher molecular weights and better fluorescent quantum efficiency than those of P3 and P4, are utilized as lighting emitters for organic light-emitting diodes (OLEDs), affording promising green and red luminescence with 0.07% and 0.14% of maximum external quantum efficiency, respectively, based on a device with an architecture of ITO/PEDOT:PSS/PTAA/the polymer emitting layer/TPBi/LiF/Al.

scholarly journals Association of large molecular weight proteasome 7 gene polymorphism with ankylosing spondylitis

1998 ◽  
Vol 41 (3) ◽  
pp. 560-562 ◽  
Author(s):  
A. Fraile ◽  
A. Nieto ◽  
J. Vinasco ◽  
Y. Bera�n ◽  
J. Mart�n ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ankylosing Spondylitis ◽  
Gene Polymorphism ◽  
Large Molecular Weight
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