bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 1,5-Diaminonaphthalene Via Electrochemical C,H-Amination of Naphthalene
Authors: Möhle Sabine , Herold Sebastian , Richter Frank , Nefzger Hartmut , Waldvogel Siegfried R. 
Published: February 2020

Since their invention in 1937, polyurethanes (PUR) have found numerous applications in our daily life.[1] A key building block for high performance polyurethanes (Vulkollan®) is 1,5-naphthalene diisocyanate, made from 1,5-diamino naphthalene. The latter is currently made by a rather laborious multistep process. Therefore, a direct and sustainable access to 1,5-naphthalene diisocyanate or the precursor diamine would be of interest. In 2013 Yoshida et al. reported a promising process for the electrochemical C,H amination of electron-rich arenes.[2,3] Through anodic pyridination at a carbon felt anode (graphite) N-arylpyridinium ions are obtained. Aminolysis with piperidine yields the corresponding primary amines. Overoxidation and the introduction of a second amino moiety are suppressed because of the positive charge of the pyridinium intermediates.
We successfully demonstrated the twofold, electrochemical C,H amination of naphthalene by employing boron-doped diamond anodes. This innovative electrode material shows a higher performance at more positive potentials.[4] The second amino functionality is, due to electrostatics, regioselectively introduced at position 5. Upon work-up 1,5-diaminonaphthalene and 1-aminonaphthalene are obtained. Currently, the reaction is optimized regarding e.g. current density and electrolyte. It is envisioned, that the positive charge of 1-pyridiniumnaphthalene can be effectively shielded through an appropriate choice of supporting electrolyte (-concentration). Thus, the second oxidation should be facilitated. Furthermore, the scope of the reaction is expanded to other polycyclic aromatic hydrocarbons, as well as other nitrogen-based nucleophiles.
References:
[1] a) O. Bayer, W. Siefken, H. Rinke, L. Orthner, H. Schild (IG Farben), DRP 728981, 1937; b) H.W. Engels, H. G. Pirkl, R. Albers, R. W. Albach, J. Krause, A. Hoffmann, H. Casselmann, J. Dormish, Angew. Chem. Int. Ed.
2013; 52, 9422–9441, Angew. Chem. 2013, 125, 9596–9616.
[2] T. Morofuji, A. Shimizu, J. I. Yoshida, J. Am. Chem. Soc. 2013, 135, 5000–5003
[3] S. R. Waldvogel, S. Möhle, Angew.
Chem. Int. Ed.
2015, 54, 6398–6399; Angew. Chem. 2015, 127, 6496–6497.
[4] B. Elsler, D. Schollmeyer, K. M. Dyballa, R. Franke, S. R. Waldvogel, Angew.
Chem. Int. Ed. 2014, 53, 5210─5213; Angew.
Chem.
2014, 126, 5311─5314.

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Electropolymerization of EDOT on Wireless Electrodes Toward Polymer Microfiber Networks
Authors: Inagi Shinsuke , Koizumi Yuki , Ohira Masato , Nishiyama Hiroki , Tomita Ikuyoshi 
Published: February 2020

Recently we reported the site-selective electroplating of metals such as Au and Pt on a conductive object used as a bipolar electrode (BPE).1 The application of alternating current (AC) voltage between the driving electrodes was found to be effective for the precise modification of the BPEs.
We report here the electropolymerization of 3,4-ethylenedioxythiophene (EDOT) and its derivatives by AC-bipolar electrolysis with the sacrificial reduction of benzoquinone.2 Poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives were found to propagate as a fiber form from the ends of Au wires used as BPEs parallel to an external electric field, without the use of templates. The effects of applied frequency and of the solvent on the morphology, growth rate and degree of branching of these PEDOT fibers were investigated. In addition, a chain-growth model for the formation of conductive material networks was also demonstrated.
References
1. Y. Koizumi, N. Shida, I. Tomita, S. Inagi, Chem. Lett.
2014, 43, 1245.
2. Y. Koizumi, N. Shida, M. Ohira, H. Nishiyama, I. Tomita, S. Inagi, Submitted.

Figure 1
Molecular Tailoring for Efficient Conversion of Near-Infrared Light in Dye-Sensitized Solar Cellsoral
Authors: Novelli Vittoria , Barbero Nadia , Magistris Claudio , Barolo Claudia , Sauvage Frédéric 
Published: February 2020

Dye-sensitized solar cells (DSCs) stand actually as a promising alternative to conventional silicon photovoltaic devices owing to lower production cost, low environmental footprint and unique properties to convert efficiently low light intensities and diffuse day light.(
1
) Today more than 14 % power conversion efficiency (PCE) has been achieved by optimizing a cocktail of organic dye in conjunction with a Co+III/+IItris(1,10-phenanthroline) redox couple.(
2
) So far, the current chemistry developed for DSC still present a lack in absorbing and converting substantially low-lying energy photons greater than λ >750 nm. With the aim to continue improving light harvesting capability of DSC for approaching closer to silicon standards, two important breakthroughs are needed: (i) reducing the internal energy loss arising from energy mismatch for electron injection and for dye regeneration (ii) extending light harvesting towards the NIR by the development of a new class of efficient sensitizers energetically well-coupled with the electronic properties of anatase TiO2 semi-conductor and electrolyte redox couple.
We have developed a series of new efficient organic sensitizers based on squaraine core-units, croconines or cyanines which are able to shift towards the red the light absorption from ca. 520 nm from the current ruthenium polypyridil-based sensitizers to as high as 830 nm. These new sensitizers not only show NIR absorption but also exhibit significantly higher molar extinction coefficients (100 000 - 320 000 mol-1cm-1) while being cost competitive.
This communication will describe these new efficient sensitizers converting up to 20% IPCE until 950 nm. Their light-to-electricity performances have been optimized by using highly diluted dye solution to promote aggregate-free self-assembled monolayer and carefully chosen electrolyte composition. Finally, the relationship between dye structure, electrolyte composition and the kinetic of charge transfers will be discussed on the basis of complementary set of techniques such as electrochemical impedance spectroscopy, time-correlated single photon-counting and ultra-fast pump-probe transient absorption spectroscopy.
1. B. O'Regan and M. Gratzel, Nature, 1991, 353, 737-740.
2. K. Kakiage, Y. Aoyama, T. Yano, K. Oya, J.-i. Fujisawa and M. Hanaya, Chem. Commun., 2015, 51, 15894-15897.
Electrochemical Characterization of Novel Organoborohydride Compounds
Authors: Cardoso David , Sequeira Cesar A.C. , Abbey Eric , Santos Diogo M.F. , Barker Josh , Bateman Chris 
Published: February 2020

Sodium borohydride (NaBH4) is a solid white powder that finds wide application as a reducing agent in organic and inorganic synthesis [1]. This compound possesses relatively mild reducing abilities, but certain applications call for reducing powers greater than NaBH4, while others require the reducing powers to be attenuated. Organic chemists have successfully tuned the reducing power of NaBH4by attaching organic electron donating or withdrawing groups to the boron center, which can also drive regio- and stereoselectivity.
These organoborohydrides have received much recent attention for their role in frustrated Lewis pair systems [2], as well as in hydrogen fuel carriers. Computational methods have established the tuning power of different organic substituents on the boron center, but experimentally quantifying reducing power remains difficult [3]. The present study seeks to quantify reducing power using electrochemical methods and elucidate the relationship between organic tuning group and reducing ability.
In this work, benzylborohydride (C7H7BH3Na) was prepared by reduction of potassium benzyltrifluoroborate with a metal hydride. The compound structure was further characterized by multinuclear NMR and FTIR. Whereas, the electrochemical characterization was carried out using a standard three-electrode setup, by cyclic voltammetry (CV) in static conditions and by linear scan voltammetry (LSV) using a rotating ring-disk electrode (RRDE) system. Platinum and gold disk macroelectrodes and microelectrodes were used to study the electrooxidation of these compounds. The organoborohydrides were tested in DMSO + 0.03 M C7H7BH3Na at temperatures ranging from 25 to 65 ºC. The results were directly compared with NaBH4solutions in the same experimental conditions.
The main electrochemical parameters were calculated, including number of exchanged electrons, charge transfer coefficient, reaction rate constant, and diffusion coefficient for the selected range of temperatures. Moreover, the activation energy for the benzylborohydride oxidation reaction was calculated assuming Arrhenius behavior.
The formation of intermediate compounds was checked by RRDE studies, elucidating the possible steps involved in the oxidation mechanism. Several other organoborohydride compounds are planned to be studied and that will allow finding a direct relationship between organic substituents and the reducing power of the borohydride center.
1. H.O. House, Modern synthesis reactions, Benjamin, W.A., Menlo Park, CA, 1972.
2. J. Paradies, Metal-free hydrogenation of unsaturated hydrocarbons employing molecular hydrogen, Angew. Chem. Int. Ed. 53 (2014) 3552.
3. Z.M Heiden, A.P. Lathem, Establishing the hydride donor abilities of main group hydrides, Organometallics 34 (2015) 1818.
Hybrid Electrocatalytic Nanomaterials for Isopropanol Oxidation
Authors: Miecznikowski Krzysztof , Adamczyk Lidia , Cox James A. , Kulesza Pawel J 
Published: February 2020

Recently, there has been growing interest in development of electrochemical energy conversion systems utilizing small organic molecules as alternative technologies to hydrogen based fuel cells. Such organic molecules as methanol, ethanol or isopropanol can be ideally oxidized to carbon dioxide. But realistically the reactions are rather slow at ambient conditions. Obviously, there is a need to develop novel electrocatalytic materials.
Platinum has been recognized as the most active catalytic metal towards oxidation of alcohols at low and moderate temperatures. But Pt anodes are readily poisoned by the strongly adsorbed intermediates, namely by CO-type species, requiring fairly high overpotentials for their removal. Up to now lot of materials have been tested as electrocatalysts for small organic molecules in acidic media, such as Pt, its alloys Pt–M (M= Ru, Sn, Rh, Pb, Ir, W or Mo) in binary or ternary form and even different methods to prepare Pt thin film electrodes. Complete oxidation of alcohols into CO2 via C–C bond cleavage is mechanistically difficult at ambient (low) temperature, and the surface of catalytic platinum readily undergoes poisoning with intermediates of the alcohols oxidation. This problem may be partially solved by applying bifunctional electrocatalysts. In general, metals, like ruthenium, tin or rod are oxophilic, which provide oxygen at low potentials and mitigates the poisoning effect by oxidizing the metastable intermediates with adsorbed water fragments.
In order to increase the overall kinetic of electrooxidation of isopropanol, we have utilized as carriers (matrices) carbon nanotubes (CNTs) modified with the cesium salt of Keggin-type heteropolyacids of molybdenum and tungsten (Cs2.5H0.5PMo12O40, Cs2.5H0.5PW12O40) or metal oxide (MoO3, ZrO2, CeO2, IrO2). The presence of metals oxide and cesium salt are capable of generating of interfacial reactive hydroxy groups on the surfaces and also increase the catalytic surface. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. Electrochemical diagnostic experiments have been supported with microscopic monitoring of morphology using transmission electron microscopy (TEM) and ATR-FTIR measurements.
Photochemical Degradation of Diclofenac Sodium By Nanophotocatalyst ZnO Doped C, N, S in Aqueous Solution Using UV Irradiation
Authors: Giahi Masoud , Taghvi Hajar 
Published: February 2020

Novel C, N, and S-doped ZnO nanoparticles were prepared by a solid phase reaction. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results showed that crystallite size of synthesized C, N, and S-doped ZnO were in nanoscale. The degradation was studied under different conditions such as the catalyst concentration, concentration of drug, initial pH value and presence of electron acceptor. The results showed that photocatalytic degradation of drug was strongly influenced by these parameters. The best conditions for the photocatalytic degradation of diclofenac sodium were obtained. The optimum concentrations of N, S, C -ZnO was found to be 0.44g/L. The photodegradation efficiency of diclofenac sodium decreased with an increase in the initial concentration of diclofenac sodium. In acidic solutions, photocatalytic degradation efficiency was higher than in alkaline solutions. The photodegradation efficiency of diclofenac sodium was accelerated by addition of a small amount of K2S2O8 and H2O2.

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Underpotential Deposition of Nickel on Cu2o Films and Its Effects on Reactivity and Stability of Cu2o Films
Authors: Fillinger Akiko , DeHority Kaitlyn , Budin Noah 
Published: February 2020

Our studies on crystal facet and reactivity relationship suggest that the (111) face of Cu2O films electrodeposited from pH 12 cupric lactate solution is a preferred surface for photogeneration of H2 from water, owing to its polar O2--termination. In order to prevent photodecomposition of this Cu2O surface, which is initiated by interaction of the terminal O2- and H+ (Cu2O + 2H+ + 2e- --> 2Cu0 + H2O), while maintaining the attraction of H+ to the surface and potentially catalyzing H2 generation, we have attempted to deposit a monolayer of nickel via underpotential deposition (UPD). Underpotential deposition on oxides has not been explored much unlike the underpotential deposition on metals as a monolayer deposition method.
Nickel was deposited on Cu2O films from a 0.08 M nickel acetate solution by applying various potentials for 1 min at room temperature. The Cu2O films with nickel deposited were dissolved in HNO3, and then the quantities of the deposited nickel at the various potentials were determined with atomic absorption spectrometry (AAS). The AAS results indicate that the underpotential deposition at -0.2 V vs. SCE (the calculated Nernst potential of the nickel solution is -0.49 V vs. SCE) deposited nickel that is equivalent to a 23 % monolayer coverage, corresponding to 60 kJ stronger interaction of Ni2+(aq) with O2- at Cu2O surface than with bulk Ni surface, as predicted for the polar Cu2O (111) face. For the estimate of the 100 % coverage of Cu2O surface, the atomic radius of Ni (124 pm) was used as well as the surface roughness of 1.09 obtained by atomic force microscopy measurements. At -0.3 V vs. SCE, more than a monolayer of nickel (205 %) was deposited.
According to the x-ray photoelectron spectroscopy (XPS), the binding energy (BE) of Ni 2p3/2 electron changed from 855 eV for -0.2 V vs. SCE UPD sample to 851 eV for -0.3 V vs. SCE UPD sample. Since the BEs of 854.6 eV and 852.6 eV have been assigned for Ni2+ and Ni0, respectively, the XPS data indicate that the full reduction of nickel at the Cu2O surface occurs at potentials more negative than -0.2 V vs. SCE.
The effects of underpotentially deposited nickel on the activity and stability of Cu2O films will be compared with respect to the deposition potential.
Solar Driven Processes at Semiconducting Metal Oxide Electrodes, Assisted By Non-Noble Metal Catalysts
Authors: Solarska Renata , Bienkowski Krzysztof , Sarnowska Marta , Augustynski Jan 
Published: February 2020

Attempts to improve performance of the semiconductor photo-electrodes used either for oxidation or reduction of species present in the electrolyte very often require presence of a catalysts However, identification of new molecular catalysts, active in often highly corrosive media or under unfavourable band energetics is a challenge. N-type mesoporous tungsten trioxide, WO3, is one of few stable semiconductor materials able to photo-electrochemically split water under solar light irradiation but it’s operational acidic environment restricts use of any catalyst to the precious metal based oxygen-evolution electrocatalysts. In an attempt to overcome this limitation, an addition to the acidic electrolyte of Keggin-type polyoxometalates (POMs) species was investigated in function of their electrocatalytic capabilities to drive oxygen evolution. The presence of this catalyst in the electrolyte makes it particularly efficient for use with nanoporous structure allowing deep penetration of the catalyst dissolved in the electrolyte. Moreover, moderate doping with metal cations of WO3 has been found to enhance visible blue light absorption of tungsten trioxide and, consequently, its photocurrent conversion efficiency. Combination of those two effects allowed achieving of record high water photooxidation currents attained under simulated solar AM 1.5G irradiation. The enhancement of anodic photocurrents will be discussed in the frame of functionalization of different mixed metal oxides with the POMs and correlated with the measurements of the amounts of oxygen evolved at the modified electrodes.
Nanodot Formation of Ferrocene-Terminated Self-Assembled Monolayers
Authors: Ikeda Katsuyoshi 
Published: February 2020

Self-assembly of molecular monolayers is a very useful technique for fabricating chemically modified electrodes with various functions. This technique enables to form a uniform molecular monolayer on a metal surface without guidance from outside. On the other hand, it is still difficult for this technique to fabricate patterned monolayers or to integrate multiple functionality within a monolayer. Although soft-lithography of self-assembled monolayers such as microcontact printing has already been reported, further advancement in forming nanoscale features of molecular monolayers is awaited for creation of multifunctional electrodes. In this study, molecular nanodots are formed on Au(111) surfaces using a novel electrochemical nanolithographic method combining reductive desorption of thiols with AuNP-assisted local stabilization of the monolayers.
The left panel of the figure shows a topographic image and I-V curves measured on nanopatterned monolayers of 4-methylbenzenethiols on Au(111) using current-AFM. As a result of the local removal of the molecular monolayers, the exposed surface showed metallic conductivity. On the other hand, the other area showed rather low conductivity with the exponential profile, indicating that the molecular layers remained with nanoscale domains. The right panel shows that average molecular nanodot sizes was controllable by alternating the size of AuNP template or by changing the ionic strength for reductive desorption. Electrochemical responses of ferrocene-terminated monolayer nanodots will be also demonstrated in the talk.
Figure (left) I-V curves measured on molecular nanodots and on the exposed Au(111) (right) Average sizes of molecular nanodots vs. sizes of AuNP templates.

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Fabrication of Different Crystalline Diamond Films and Their Application As Anodes for the Oxidation of Human Urine
Authors: Li Zhongjian , Li Hao , Zhang Xingwang , Lei Lecheng , Yang Bin 
Published: February 2020

Diamond shows several extreme outstanding properties, such as high Young's modulus, low surface roughness and chemical inertness et al. Thus, it has been used extensively in many fields including microelectromechanical systems, electron ﬁeld emitters and electrochemistry. The diamond film will be conductive after boron-doping, and therefore it can be used as a popular candidate anode for the electrochemical oxidation of organic containments in aqueous solution since it shows a wide potential window, low background current, high electrochemical stability and corrosion resistance. Water recycling would be the most realistic and economical way for human being in confined space station where it is cut off from the atmosphere for a long time.
In our work, hot filament chemical vapor deposition (HFCVD) method was employed to fabricate microcrystalline and nanocrystalline diamond films using only hydrogen and methane as precursor. Different factors such as methane concentration, substrate temperature and reaction pressure were studied and it reveals that methane concentration is the major contribution on the morphology change. The resulted morphology of diamond films changed from microcrystalline to nanocrystalline when the methane concentration increased from 2% to 10%. Boron-doped microcrystalline and nanocrystalline diamond films were both used as anodes for the electrochemical degradation of human urine. They show comparable efficiency on the degradation of organic compounds on both electrodes, and while show a small difference on the oxidation of chlorine ions and ammonia ions. However, the nanocrystalline diamond anode shows a longer lifetime due to the lower surface roughness in comparison with the microcrystalline diamond anode. Herein, the nanocrystalline diamond anode is promising for the industrial applications in the electrochemical oxidation of wastewater in the future.
Voltammetric Determination of Mercury in Biological Samples Using Crown Ether/Multiwalled Carbon Nanotube-Based Sensor
Authors: Hassan Rabeay , Kamel Manal , N.A. Hassan Hassan , Khaled Elmorsy 
Published: February 2020

An electrochemical assay for sensitive and selective determination of mercury was suggested. Preparation, characterization, and testing the electro-catalytic activity of Crown-ether/multi-walled carbon nanotubes (MWCNTs) / CPEs were performed. The voltammetric responses of modified electrodes with various sensing elements and nanomaterials were carefully investigated. Consequently, improving the sensitivity and selectivity were achieved using a combination of 12-crwon-4- ether and MWCNTs (10% w/w for each). A linear response was observed from 5 -110 µg/ml, with the detection limit (S/N=3) of 0.25 µg/ml. The method was interference free from many species and successfully applied for the determination of mercury in blood, urine or tab-water samples with a high accuracy and precision comparable with the reference method (Atomic Absorption Spectroscopy AAS).

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