Synthesis and Incorporation of Thienylene Vinylene Oligomers in Main-Chain Copolymers

1997 ◽  
Vol 488 ◽  
Author(s):  
L. G. Madrigal ◽  
E. H. Elandaloussi ◽  
C. W. Spangler
Keyword(s):  
Main Chain ◽  
Radical Cations ◽  
Synthetic Approach ◽  
Chemical Doping ◽  
Third Order ◽  
The Past ◽  
Growth Reaction ◽  
Oxidative Doping ◽  
Step Growth ◽  
Conductivity Behavior

AbstractPoly [2,5-thienylene vinylene] (PTV) has been studied extensively over the past decade for both its metallic conductivity behavior upon chemical doping, as well as its interesting third order nonlinear optical properties. PTV oligomers have been synthesized by our group 1, as well as others 2, and the formation of polaron-like radical-cations or bipolaron-like dications by oxidative doping has been demonstrated. In this paper we describe a general synthetic approach to PTV oligomers functionalized for copolymer formation by step-growth reaction.

Click Reactions in Chemistry of Triterpenes - Advances Towards Development of Potential Therapeutics

2018 ◽  
Vol 25 (5) ◽  
pp. 636-658 ◽  
Author(s):  
Jan Pokorny ◽  
Lucie Borkova ◽  
Milan Urban
Keyword(s):  
Biological Activities ◽  
Synthetic Approach ◽  
Clinical Use ◽  
New Approach ◽  
Click Reactions ◽  
Drug Candidates ◽  
The Past ◽  
Low Toxicity ◽  
New Compounds ◽  
Potential Therapeutics

Triterpenoids are natural compounds with a large variety of biological activities such as anticancer, antiviral, antibacterial, antifungal, antiparazitic, antiinflammatory and others. Despite their low toxicity and simple availability from the natural resources, their clinical use is still severely limited by their higher IC50 and worse pharmacological properties than in the currently used therapeutics. This fact encouraged a number of researchers to develop new terpenic derivatives more suitable for the potential clinical use. This review summarizes a new approach to improve both, the activity and ADME-Tox properties by connecting active terpenes to another modifying molecules using click reactions. Within the past few years, this synthetic approach was well explored yielding a lot of great improvements of the parent compounds along with some less successful attempts. A large quantity of the new compounds presented here are superior in both activity and ADME-Tox properties to their parents. This review should serve the researchers who need to promote their hit triterpenic structures towards their clinical use and it is intended as a guide for the chemical synthesis of better drug candidates.

scholarly journals The axion-baryon coupling in SU(3) heavy baryon chiral perturbation theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas Vonk ◽  
Feng-Kun Guo ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Power Counting ◽  
Flavor Symmetry ◽  
Chiral Perturbation ◽  
Third Order ◽  
Stellar Objects ◽  
The Past ◽  
Dense Nuclear Matter

Abstract In the past, the axion-nucleon coupling has been calculated in the framework of SU(2) heavy baryon chiral perturbation theory up to third order in the chiral power counting. Here, we extend these earlier studies to the case of heavy baryon chiral perturbation theory with SU(3) flavor symmetry and derive the axion coupling to the full SU(3) baryon octet, showing that the axion also significantly couples to hyperons. As studies on dense nuclear matter suggest the possible existence of hyperons in stellar objects such as neutron stars, our results should have phenomenological implications related to the so-called axion window.

scholarly journals Cation Doping Approach for Nanotubular Hydrosilicates Curvature Control and Related Applications

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 654
Author(s):  
Andrei A. Krasilin ◽  
Ekaterina K. Khrapova ◽  
Tatiana P. Maslennikova
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Morphological Changes ◽  
High Technology ◽  
Synthetic Approach ◽  
Cation Doping ◽  
The Past ◽  
Technology Applications ◽  
Curvature Control ◽  
Uptake And Release

The past two decades have been marked by an increased interest in the synthesis and the properties of geoinspired hydrosilicate nanoscrolls and nanotubes. The present review considers three main representatives of this group: halloysite, imogolite and chrysotile. These hydrosilicates have the ability of spontaneous curling (scrolling) due to a number of crystal structure features, including the size and chemical composition differences between the sheets, (or the void in the gibbsite sheet and SiO2 tetrahedron, in the case of imogolite). Mineral nanoscrolls and nanotubes consist of the most abundant elements, like magnesium, aluminium and silicon, accompanied by uncontrollable amounts of impurities (other elements and phases), which hinder their high technology applications. The development of a synthetic approach makes it possible to not only to overcome the purity issues, but also to enhance the chemical composition of the nanotubular particles by controllable cation doping. The first part of the review covers some principles of the cation doping approach and proposes joint criteria for the semiquantitative prediction of morphological changes that occur. The second part focuses on some doping-related properties and applications, such as morphological control, uptake and release, magnetic and mechanical properties, and catalysis.

Main-chain PPEGMEMA-b-PBTFVPP-b-PPEGMEMA perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymer: synthesis and self-assembly

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 77388-77398 ◽  
Author(s):  
Chun Feng ◽  
Wenqiang Yao ◽  
Guolin Lu ◽  
Yongjun Li ◽  
Xiaoyu Huang
Keyword(s):  
Self Assembly ◽  
Triblock Copolymer ◽  
Main Chain ◽  
Triblock Copolymers ◽  
Aryl Ether ◽  
Step Growth ◽  
Aba Triblock Copolymer ◽  
Transformation Strategy

A novel perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymers were synthesized via the site transformation strategy using sequential thermal [2π + 2π] step-growth cycloaddition polymerization and ATRP.

Synthesis Approaches For Improving the Nonlinear Optical Properties of Pbz Polymers

1987 ◽  
Vol 109 ◽  
Author(s):  
James F. Wolfe ◽  
Bock H. Loo ◽  
Robert A. Sanderson ◽  
Steven P. Bitler
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Main Chain ◽  
Second Order ◽  
Carboxyl Group ◽  
Amino Group ◽  
Flexible Polymers ◽  
Third Order ◽  
Guest Molecules ◽  
Dimethylamino Group

ABSTRACTThe synthesis of three types of functionalized benzazole structures is described. A centrosymmetric dihydroxy-benzobisthiazole has been synthesized for incorporation in flexible polymers having rigid, conjugated, third order nlo active units in the main chain. Benzazole structures terminated with an N,N-dimethylamino group and a carboxyl group have been synthesized for use as second order nlo pendants with flexible polymers. Benzazole structures terminated with an N,N-dimethylamino group and an amino group have been synthesized as precursors to second order nlo guest molecules.

scholarly journals Geometrias e posicionamento espacial de antigas cicatrizes de escorregamentos em encostas nas cabeceiras do rio Mãe Luzia, Treviso – Santa Catarina, Brasil

2020 ◽  
Vol 42 ◽  
pp. e104
Author(s):  
William De Oliveira Sant Ana ◽  
Álvaro José Back ◽  
Gean Paulo Michel ◽  
Nilzo Ivo Ladwig ◽  
Danrlei De Conto
Keyword(s):  
Second Order ◽  
Aerial Photographs ◽  
Geometric Correction ◽  
Negative Consequences ◽  
Third Order ◽  
Santa Catarina ◽  
The Third ◽  
The Past

The occurrence of landslides can result in negative consequences for the ecosystems and society. On the understanding of these events, aerial photographs constitute an important collection for multitemporal investigations, making it possible to obtain the accuracy of surface coordinates, since they are georeferenced and orthorectified. The main objective of this work is to georeferentiate and orthorectify aerial photographs and to make comparisons in the calibration of geometries and positioning of old scars of landslides on slopes. The study area is a detail of 94 ha (0.94 km²) of the headwaters of the Mãe Luzia River, municipality of Treviso (SC), site with landslide records in 1978. To reach the scope, the georeferencing and feature editions were performed with geoprocessing software and orthorectification with the Digital Photogrammetric Station of the E-Foto project. The total area of scars obtained in the first polynomial order was 5 hectares, in the second order 4.98, in the third order 5.14 and, after orthorectification, 5.51 hectares. The altimetric variation produced greater distortions between sites of depressed topography, after orthorectification, there was a geometric correction of the edited polygons, notably in the bottom of the valleys. It is concluded that it is important not only to georeferentiate, but also to orthorectify old photographs, which have a great amount of valuable information of the past landscape.

OTHER SHUKSHIN: NOTES ON CONTEMPORARY STUDIES OF SHUKSHIN’S WORKS

2020 ◽  
Vol 10 (2) ◽  
pp. 39-52
Author(s):  
A.I. Kulyapin ◽  
Keyword(s):  
Doctoral Degree ◽  
Synthetic Approach ◽  
Historical Time ◽  
Holistic Model ◽  
The Past ◽  
90Th Anniversary ◽  
Scientific Significance ◽  
Political Essays ◽  
Film Making ◽  
First Time

The article is devoted to the review of monographs on the work of V.M. Shukshin, published over the past five years. Researchers of the creative heritage of the writer and film director managed to offer new prospects in the study of his works. In the monograph by D.V. Maryin, “The non-artistic work of V.M. Shukshin,” for the first time, letters, documentary autobiographies, draft notes, and social and political essays of the writer were systematically studied. The scientific significance of the research by Altai philologists “Semiotics of the artistic space of V.M. Shukshin” and “Geopoetics of V.M. Shukshin” consists in attempts to describe a holistic model of the writer’s artistic world. A book by I.V. Shestakova, “The artistic and visual principles of cinema by V.M. Shukshin,” is distinguished by a synthetic approach to Shukshin’s creativity. According to the author of this work, Shukshin’s film making is a single space for the interaction of literary, pictorial, and musical forms of arts. In addition to film critics, historians, philosophers and sociologists actively joined in the work on Shukshin’s works. The textbook by Prof. S.I. Grigoriev, (Post-Doctoral degree in Sociology) has run through several editions. S.V. Tsyb, Barnaul historian, had published his book entitled “V.M. Shukshin and historical time” by the 90th anniversary of Shukshin.

Iterative step-growth synthesis and degradation of unimolecular polyviologens under mild conditions

2022 ◽  
Author(s):  
Abigail Delawder ◽  
Mark S. Palmquist ◽  
Jovelt M. Dorsainvil ◽  
Nathan D. Colley ◽  
Tiana M. Saak ◽  
...  
Keyword(s):  
Main Chain ◽  
Addition Method ◽  
Mild Conditions ◽  
Step Growth ◽  
Synthesis And Degradation

An iterative step-growth addition method was used to expedite the gram-scale synthesis of main-chain polyviologens by several days, while also producing the longest main-chain polyviologen (i.e., 26 viologen subunits) reported...

Design of New Copolymers for Photonics Applications: Incorporation of Nlo-Active Chromophores with Well-Defined Conjugation Lengths

1995 ◽  
Vol 413 ◽  
Author(s):  
Charles W. Spangler ◽  
Mingqian He
Keyword(s):  
Nonlinear Optical ◽  
Near Infrared ◽  
Phenylene Vinylene ◽  
Third Order ◽  
Conductive Materials ◽  
Oxidative Doping ◽  
Doped Polymers ◽  
Degree Of Control ◽  
Neutral Polymer ◽  
Absorption Characteristics

ABSTRACTElectroactive polymers such as poly [p-phenylene vinylene] (PPV) and poly [2,5-thienylene vinylene] (PTV) have been shown to yield highly conductive materials upon oxidative doping,1 and to display enhanced third order nonlinear optical response.2 Optical absorption spectra for either neutral or doped polymers, however, are quite broad, extending well into the visible for the neutral polymer and into the near infrared (NIR) for the doped polymers, with little evident fine structure. For certain nonlinear optical (NLO) applications, this can lead to undesirable absorption losses and resonance phenomena. We would like to describe how copolymers incorporating oligomeric dithienylpolyene segments may be designed so as to give some degree of control over the polymer absorption characteristics in either neutral or oxidized form.

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