scholarly journals Insight into the template effect of vesicles on the laccase-catalyzed oligomerization of N-phenyl-1,4-phenylenediamine from Raman spectroscopy and cyclic voltammetry measurements

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Aleksandra Janoševic Ležaić ◽  
Sandra Luginbühl ◽  
Danica Bajuk-Bogdanović ◽  
Igor Pašti ◽  
Reinhard Kissner ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Redox Activity ◽  
Salt Form ◽  
Template Effect ◽  
Structural Units ◽  
Redox Active ◽  
First Time ◽  
Insight Into

Abstract We report about the first Raman spectroscopy study of a vesicle-assisted enzyme-catalyzed oligomerization reaction. The aniline dimer N-phenyl-1,4-phenylenediamine (= p-aminodiphenylamine, PADPA) was oxidized and oligomerized with Trametes versicolor laccase and dissolved O2 in the presence of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) vesicles (80–100 nm diameter) as templates. The conversion of PADPA into oligomeric products, poly(PADPA), was monitored during the reaction by in situ Raman spectroscopy. The results obtained are compared with UV/vis/NIR and EPR measurements. All three complementary methods indicate that at least some of the poly(PADPA) products, formed in the presence of AOT vesicles, resemble the conductive emeraldine salt form of polyaniline (PANI-ES). The Raman measurements also show that structural units different from those of “ordinary” PANI-ES are present too. Without vesicles PANI-ES-like products are not obtained. For the first time, the as-prepared stable poly(PADPA)-AOT vesicle suspension was used directly to coat electrodes (without product isolation) for investigating redox activities of poly(PADPA) by cyclic voltammetry (CV). CV showed that poly(PADPA) produced with vesicles is redox active not only at pH 1.1–as expected for PANI-ES–but also at pH 6.0, unlike PANI-ES and poly(PADPA) synthesized without vesicles. This extended pH range of the redox activity of poly(PADPA) is important for applications.

scholarly journals Erratum: Insight into the template effect of vesicles on the laccase-catalyzed oligomerization of N-phenyl-1,4-phenylenediamine from Raman spectroscopy and cyclic voltammetry measurements

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Aleksandra Janoševic Ležaić ◽  
Sandra Luginbühl ◽  
Danica Bajuk-Bogdanović ◽  
Igor Pašti ◽  
Reinhard Kissner ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Template Effect ◽  
Insight Into

In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy

Nanoscale ◽  
2015 ◽  
Vol 7 (40) ◽  
pp. 16952-16959 ◽  
Author(s):  
Kaige Zhang ◽  
Gongke Li ◽  
Yuling Hu
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Catalytic Reactions ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Nanocrystalline Magnesium Oxide ◽  
Insight Into

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water.

Combined synchrotron x-ray diffraction and micro-Raman for following in situ the growth of solution-deposited YBa2Cu3O7 thin films

2005 ◽  
Vol 20 (12) ◽  
pp. 3270-3273 ◽  
Author(s):  
F. Berberich ◽  
H. Graafsma ◽  
B. Rousseau ◽  
A. Canizares ◽  
R. Ramy Ratiarison ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Additional Information ◽  
Micro Raman Spectroscopy ◽  
High Temperature Process ◽  
Structural Growth ◽  
Metal Organic ◽  
Insight Into

A unique combination of in situ synchrotron x-ray diffraction and in situ micro-Raman spectroscopy was used to study the growth process of YBa2Cu3O6+x films obtained by metal organic decomposition using trifluoroacetate precursor on LaAlO3 substrates. The techniques give complementary information: x-ray diffraction gives insight into the structural growth, whereas micro-Raman spectroscopy gives information of the chemical composition with additional information on the texture. To perform both experiments in situ, a special high-temperature process chamber was designed.

scholarly journals Electrochemistry and surface-enhanced Raman spectroscopy of CTAB modulated interactions of magnetic nanoparticles with biomolecules

RSC Advances ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 3628-3634 ◽  
Author(s):  
Delina Joseph ◽  
Raul D. Rodriguez ◽  
Akash Verma ◽  
Elaheh Pousaneh ◽  
Dietrich R. T. Zahn ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Magnetic Nanoparticles ◽  
Electrochemical Behavior ◽  
Surface Enhanced Raman Spectroscopy ◽  
Molecular Associations ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Insight Into

In this study, cyclic voltammetry was used to unearth the electrochemical behavior of MNPs/CTAB and their interaction with biomolecules whereas SERS provided an insight into the mode of interaction in these molecular associations.

scholarly journals Fatigue failure analysis of three-layer Zr–Ti/Zr–Steel composite plates: an insight into the evolution of cracks initiated at the interfaces

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Aleksander Karolczuk ◽  
Andrea Carpinteri ◽  
Grzegorz Robak ◽  
Szymon Derda ◽  
Mariusz Prażmowski
Keyword(s):  
Mechanical Property ◽  
Fatigue Failure ◽  
Adiabatic Shear Band ◽  
Fatigue Cracks ◽  
Composite Plates ◽  
Adiabatic Shear ◽  
Steel Composite ◽  
First Time ◽  
Insight Into

Abstract Initiation and evolution of fatigue cracks at the interfaces in three-layer Zr–Ti/Zr–Steel composites is herein examined by in situ optical microscopy for the first time. Specimens cut out from three composite plates comprising Zr 700, Ti Gr. 1, and P265GH steel layers have been subjected to uniaxial fatigue cyclic loading. It is found that mechanical property mismatch between layers and defects at the interfaces can reduce the fatigue life of composite plates. An insight into the evolution of cracks initiated at the interfaces reveals that (1) most of the cracks grow into adjacent layers along two distinct planes, and (2) these cracks could lead to the fatigue failure of composites. One of these planes coincides with the adiabatic shear band orientation found in Ti Gr. 1 and Zr 700 layers. The interfaces in multilayer metallic composite could have excellent fatigue strength depending on their structural properties.

Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-ray Diffraction, Part II: Natural Ageing

2020 ◽  
Vol 41 (4) ◽  
pp. 177-203
Author(s):  
Lynn B. Brostoff ◽  
Cynthia Connelly Ryan ◽  
Isabella Black
Keyword(s):  
Raman Spectroscopy ◽  
Amorphous Material ◽  
Aqueous Media ◽  
Gum Arabic ◽  
Artificial Ageing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Paint Films ◽  
First Time

AbstractThis study explores the natural alteration of verdigris, both in the form of neutral verdigris (Cu(II) (CH3COO)2⋅H2O) and basic verdigris (Cu(II)x(CH3COO)y(OH)z ⋅nH2O), through combined Raman spectroscopy and X-ray diffraction investigation of samples created seven to eleven years prior to analysis. The naturally aged paint films of neutral or basic verdigris in gum arabic on paper and parchment provide insight into the pigment’s well-known instability relevant to historical works in aqueous media on maps, prints, books and manuscript materials. The latter historical application is an area that has received far less attention than alteration of verdigris in oil-based paint films. Findings shed new light on alternate pathways for conversion of neutral verdigris to basic verdigris, including the formation of a previously unknown form of verdigris and amorphous material on alkaline paper substrates. Additionally, we demonstrate for the first time that copper hydroxyl chlorides can form in situ from neutral verdigris, in this case on parchment that has a chlorine-rich surface. These results advance our understanding of neutral verdigris alteration, and complement results from our prior artificial ageing study. Both studies point to neutral verdigris as the historically more important form throughout its heyday. Improved understanding of neutral verdigris instability and its alteration pathways are critical for confident identification of the pigment in historical works, leading to better risk assessment of collections of verdigris-containing heritage, such as maps.

scholarly journals Electrochemical Nozaki–Hiyama–Kishi Coupling: Scope, Applications, and Mechanism

2021 ◽  
Author(s):  
Yang Gao ◽  
david hill ◽  
wei hao ◽  
Brendon J. McNicholas ◽  
julien Vantourout ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Bond Formation ◽  
Active Esters ◽  
Vinyl Halides ◽  
Redox Active ◽  
Chemical Techniques ◽  
Detailed Kinetics ◽  
Limited Scope

One of the most oft-employed methods for C–C bond formation involving the coupling of vinyl-halides with aldehydes catalyzed by Ni and Cr (Nozaki–Hiyama–Kishi, NHK) has been rendered more practical using an electroreductive manifold. Although early studies pointed to the feasibility of such a process those precedents were never applied by others due to cumbersome setups and limited scope. Here we show that a carefully optimized electroreductive procedure can enable a more sustainable approach to NHK, even in an asymmetric fashion on highly complex medicinally relevant systems. The e-NHK can even enable non-canonical substrate classes, such as redox-active esters, to participate with low loadings of Cr when conventional chemical techniques fail. A combination of detailed kinetics, cyclic voltammetry, and in situ UV-vis spectroelectrochemistry of these processes illuminates the subtle features of this mechanistically intricate process.

scholarly journals Persistent and Reversible Solid Iodine Electrodeposition in Nanoporous Carbons

2020 ◽  
Author(s):  
Christian Prehal ◽  
Harald Fitzek ◽  
Gerald Kothleitner ◽  
Volker Presser ◽  
Bernhard Gollas ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Volume Fraction ◽  
Stochastic Modelling ◽  
Redox Activity ◽  
Potential Candidate ◽  
Nanoporous Carbons ◽  
In Situ Raman Spectroscopy ◽  
Hybrid Supercapacitors ◽  
In Situ Raman

Aqueous iodine based electrochemical energy storage is considered a potential candidate to improve sustainability and electrochemical performance of current battery and supercapacitor technology. It harnesses the redox activity of iodide, iodine and polyiodide species in the confined geometry of nanoporous carbon electrodes. However, current descriptions of the electrochemical reaction mechanism to interconvert these species are elusive. Here we show that in nanoporous carbons electrochemical oxidation of iodide forms persistent solid iodine deposits. Confinement slows down dissolution into triiodide and pentaiodide, responsible for otherwise significant self-discharge via shuttling. The main tools for these insights are in situ Raman spectroscopy and in situ small and wide angle X-ray scattering (in situ SAXS/WAXS). In-situ Raman spectroscopy confirms the formation of triiodide and pentaiodide during iodide oxidation. Besides polyiodides, remarkable amounts of solid iodine are deposited in the carbon nanopores, as detected by in situ SAXS/WAXS. Combined with stochastic modelling, in situ SAXS allows quantifying the solid iodine volume fraction and visualizing the iodine structure on 3D lattice models at the sub-nanometer scale. Based on the derived mechanism we demonstrate strategies for improved iodine pore filling capacity and prevention of self-discharge, applicable to hybrid supercapacitors and batteries.<br>

Sign in / Sign up

Export Citation Format

Share Document