scholarly journals Dye-stimulated control of conducting polypyrrole morphology

RSC Advances ◽  
2017 ◽  
Vol 7 (81) ◽  
pp. 51495-51505 ◽  
Author(s):  
Stanislav Valtera ◽  
Jan Prokeš ◽  
Jitka Kopecká ◽  
Martin Vrňata ◽  
Miroslava Trchová ◽  
...  
Keyword(s):  
Functional Groups ◽  
Azo Dyes ◽  
Aqueous Media ◽  
Supramolecular Structures ◽  
Conducting Polypyrrole

Three azo dyes bearing hydrophilic functional groups at different positions on a hydrophobic naphthylphenyldiazene skeleton were used as structure-guiding agents in the synthesis of highly organised supramolecular structures of PPy in aqueous media.

scholarly journals Non-Enzymatic Desymmetrization Reactions in Aqueous Media

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 720
Author(s):  
Satomi Niwayama
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Functional Groups ◽  
Organic Compounds ◽  
Recent Progress ◽  
Aqueous Media ◽  
Building Blocks ◽  
Organic Reactions ◽  
Environmentally Benign ◽  
Enzymatic Desymmetrization

Symmetric organic compounds are generally obtained inexpensively, and therefore they can be attractive building blocks for the total synthesis of various pharmaceuticals and natural products. The drawback is that discriminating the identical functional groups in the symmetric compounds is difficult. Water is the most environmentally benign and inexpensive solvent. However, successful organic reactions in water are rather limited due to the hydrophobicity of organic compounds in general. Therefore, desymmetrization reactions in aqueous media are expected to offer versatile strategies for the synthesis of a variety of significant organic compounds. This review focuses on the recent progress of desymmetrization reactions of symmetric organic compounds in aqueous media without utilizing enzymes.

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

ELECTRIC-FIELD DEPENDENCE OF MOLECULAR CONFORMATIONS OBSERVED BY USING SCANNING TUNNELING MICROSCOPY

NANO ◽  
2008 ◽  
Vol 03 (02) ◽  
pp. 83-94
Author(s):  
XIAO JING MA ◽  
RUI ZHANG ◽  
YONG TAO SHEN ◽  
XIAO HUI QIU ◽  
YAN LIAN YANG ◽  
...  
Keyword(s):  
Electric Field ◽  
Scanning Tunneling Microscopy ◽  
Functional Groups ◽  
Field Dependence ◽  
Conformational Changes ◽  
Supramolecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Molecular Conformations ◽  
Electric Field Dependence

We review the progress in observation of electrically induced conformational changes of a range of single molecules and molecular assemblies using scanning tunneling microscopy (STM). Recent results using species with optical active functional groups and supramolecular structures confirmed the previously observed effects that the cholesterol molecules with soft linkers have the conformational bistability when switching the bias polarity, while no discernable changes were observed for the mesogen molecules, containing rigid linking units. In addition, it was also observed that the linker units could have appreciable impacts on the assembling characteristics.

scholarly journals Visualization of the Stimuli-responsive Surface Behavior of Functionalized Wood Material by Chemical Force Microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Claudia Gusenbauer ◽  
Etienne Cabane ◽  
Notburga Gierlinger ◽  
Jérôme Colson ◽  
Johannes Konnerth
Keyword(s):  
Functional Groups ◽  
Cross Sections ◽  
Adhesion Force ◽  
Aqueous Media ◽  
Surface Characteristics ◽  
Solution Temperature ◽  
Characterization Methods ◽  
Force Microscopy ◽  
Chemical Force Microscopy ◽  
Chemical Force

AbstractThe hierarchical and porous wood structure provides a stable scaffold to design functionalized lignocellulosic materials with extended properties by chemical modification techniques. However, proper nanoscale characterization methods for these novel materials are needed to confirm the presence of the added functionality and to locate the introduced functional groups with high spatial resolution. Chemical force microscopy is a suitable characterization method to distinguish chemical surface characteristics by scanning the samples surface with a functionalized tip. We report the application of this nanotechnology method on both, unmodified and functionalized wood samples to confirm the thermo-responsive behavior of poly(N-isopropylacrylamide) (PNIPAM) modified spruce wood. By performing force measurements on ultra-microtomed surfaces, adhesion force differences on the analysed structure are monitored and reveal the location and functionality of introduced functional groups. The modified samples are scanned below and above their lower critical solution temperature with a hydrophobic tip in aqueous media to observe adhesion changes. Additionally, confocal Raman microscopy support the chemical force microscopy measurements by revealing the success of the modification and the distribution of PNIPAM across the sample cross-sections. The results show that PNIPAM is mainly located in wood cell wall areas close to the lumen in early- and transitionwood.

Deciphering effects of functional groups and electron density on azo dyes degradation by graphene loaded TiO2

2015 ◽  
Vol 357 ◽  
pp. 1064-1071 ◽  
Author(s):  
Qian Zhang ◽  
Xiao Liang ◽  
Bor-Yann Chen ◽  
Chang-Tang Chang
Keyword(s):  
Electron Density ◽  
Functional Groups ◽  
Azo Dyes ◽  
Dyes Degradation

A structural study of seven salt forms of sulfonated azo dyes containing nitrile functional groups

2013 ◽  
Vol 97 (1) ◽  
pp. 100-104 ◽  
Author(s):  
Catherine Astbury ◽  
Linda K. Conway ◽  
Cheska Gillespie ◽  
Kirsty Hodge ◽  
Elaine Innes ◽  
...  
Keyword(s):  
Functional Groups ◽  
Structural Study ◽  
Azo Dyes ◽  
Salt Forms ◽  
Sulfonated Azo Dyes

Original disymmetric bolaforms bearing at least one sulfobetaine head; synthesis and surface properties

2001 ◽  
Vol 79 (7) ◽  
pp. 1153-1158 ◽  
Author(s):  
Souad Souirti ◽  
Michel Baboulène
Keyword(s):  
Surface Properties ◽  
Functional Groups ◽  
Efficient Method ◽  
Aqueous Media ◽  
Critical Micellar Concentration ◽  
Excellent Yield ◽  
Wide Range ◽  
Self Aggregation ◽  
Cationic Amphiphile

We describe a simple and efficient method for the synthesis of disymmetric bolaforms bearing at least one sulfobetaine head. In this process, we could introduce successively on α, ω-bis(dialkylamino) alkane a sulfobetaine head and a cationic, a sulfobetaine, or a carboxybetaine head, in excellent yield. This is the first synthesis of disymmetric sulfobetaine bolaforms. The method is easily generalized to various types of head functional groups. The wide range of bolaforms produced by this method has been exploited to study their surface properties and to determine the respective roles of the polar heads and the lengths of the spacers (n) on self-aggregation in aqueous media. A critical micellar concentration (cmc) was observed with the compounds with a spacer of 12 carbon atoms (n = 12). Micellization appeared to be consistent with a "wicket-like" conformation, which did not appear to form with the n = 8 compounds.Key words: disymmetric bolaform, sulfobetaine, carboxybetaine, cationic amphiphile, synthesis, surface properties.

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