bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Power Glucose/O2 Biofuel Cell Constructed from MgO-Temlated Carbon Modified Carbon Cloth
Authors: Niiyama Ayumu , Tsujimura Seiya 
Published: February 2020

Enzymatic biofuel cells (EBFCs) based on enzyme electrocatalysts are devices to directly convert chemical energy of glucose and alcohol to electronical energy. EBFCs gather attention as a power source of wearable electronic sensor devices because they have high biocompatibility. In this paper, we report a glucose/O2 EBFC using flexible carbon cloth electrodes modified with mesoporous carbon particle, which shows high power density as high as 2 mW cm-2. Moreover, the capacity of the BFCs can be controlled by the mole number of glucose added.
Porous carbon electrode was fabricated by modifying the MgO-templated mesoporous carbon (MgOC) on carbon cloth in order to enlarge surface area and to immobilize enzyme and redox mediator on electrode surface. MgOC is a kind of pore size-controlled porous carbon; mesopore size can be controlled by alternating the MgO template size. For the anode catalyst, flavin adenine dinucleotide dependent glucose dehydrogenase (FAD-GDH) from Aspergillus terreus was used. Naphthoquinones (NQ) were used as anode mediator. FAD-GDH and NQ were modified on the anode 0.19 and 1.5 mg cm-2, respectively. For the oxygen-reducing cathode, bilirubin oxidase (BOD) was used as enzyme, and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid ammonium salt) (ABTS) as mediator. BOD and ABTS were modified on the cathode 1.25 and 1.25 mg cm-2, respectively. 1.0 M phosphate buffer (pH = 7.0) was used as an electrolyte. A cellophane sheet was sandwiched between the anode and cathode as a separator.
Figure 1 shows the cell power (solid lines) and cell voltage (broken lines) as a function of current density of the EBFCs. The maximum output power density of BFCs using 1,2-NQ and 1,4-NQ for anode mediators were 1.69 and 2.06 mW cm-2, receptively, because the redox potential of 1,4-NQ is more negative than that of 1,2-NQ. Figure 2 shows the cell capacity of the BFCs as a function of glucose concentration added to the cell. The capacity of the cell increased linear with an increase of the mole number of glucose.

Figure 1
Electrochemical Reduction of Alkenes Mediated By Vitamin B12 Model Complex
Authors: Shimakoshi Hisashi , Zhongli Luo , Hisaeda Yoshio 
Published: February 2020

Naturally-occurring B12(cobalamin)-dependent enzymes catalyze various molecular transformations that are of particular interest from the viewpoint of biological chemistry as well as synthetic organic chemistry and catalytic chemistry. The CoI species of B12 derivative is widely known as a supernucleophile that forms an alkylated complex by reaction with an alkyl halide.1 The alkylated complex is a useful reagent for forming radical species as the cobalt-carbon bond is readily cleaved homolytically by photolysis. Recently, application of CoI complex for proton reduction was extensively studied and electrochemical hydrogen evolutions by cobalt complex have been reported.2 In these studies, Co-H complex is thought to be an intermediate for hydrogen evolution. These results prompted us to investigate application of cobalamin derivative for new bio-isnpired reaction.3 The electrochemically generated CoI species of B12 derivative may reacts with proton (CF3COOH, CH3COOH etc..) to form Co-H complex, and can utilize for alkene reduction (Figure 1). Scope of substrate, detailed reaction mechanism, comparison to catalysis of other cobalt complex will be reported.

References

(1) a) M. Giedyk, H. Shimakoshi, K. Goliszewska, D. Gryko, Y. Hisaeda, Dalton Trans., 2016, in press (Inside cover); b) H. Shimakoshi, Z. Luo, T. Inaba, Y. Hisaeda, Dalton Trans., 2016, in press (Back cover).
(2) a) V. Artero, M. Chavarot-Kerlidou, and M. Fontecave, Angew. Chem. Int. Ed., 50, 7238 (2011), b) W. T. Eckenhoff, R. Eisenberg, Dalton Trans, 41, 13004 (2011).
(3) H. Shimakoshi and Y. Hisaeda, ChemPlusChem, 79, 1250 (2014) (Back cover).

Figure 1
Competition Studies and the Use of Mechanistic Insight to Overcome Synthetic Barriers
Authors: Moeller Kevin D , Perkins Robert J , Gonzalez Luisalberto , Feng Ruozhu 
Published: February 2020

Because intramolecular anodic olefin coupling reactions involve a reversal in polarity of a normally nucleophilic olefin, they can be used to develop entirely new pathways to a variety of molecules. The reactions are compatible with a wide variety of functional groups, the generation of fused, bridged, and spirocyclic ring skeletons, and the formation of quaternary carbons. However, not all anodic olefin coupling reactions work. The reactions are triggered by the formation of a highly reactive radical cation intermediate. If the desired reaction pathway is not fast enough, then the radical cation will initiate undesirable reaction pathways, often involving elimination, fragmentation, or solvent trapping. When this occurs, the question quickly becomes what can be done to solve the problem and channel the reaction down a more productive pathway?
The best way to address this question has been to carefully probe the mechanism of the reactions, identify the nature of the undesirable reactions, and then manipulate the relative rates of the reactions available to the radical cation to favor the process that is wanted. Several steps in the reaction can be important, but two play an especially important role (Scheme 1). First, the rate of the cyclization is important. If the cyclization is too slow, then side reactions involving the reactive radical cation will begin to dominate. The rate of the second oxidation (k2) is also critical for the success of the reaction. Many radical cyclizations are reversible and in those cases the loss of the second electron helps to drive the product to completion.
Understanding these principles is essential for the design of more complex reactions, and in the talk to be presented, a series of new anodic cyclization reactions (Scheme 2) will be used to highlight the important interplay between mechanistic considerations and synthetic design. Each of the reactions discussed will involve a transformation that was originally a failure but is now a cornerstone of ongoing synthetic efforts.

Figure 1
Dissymmetric Bis(dipyrrinato)Zinc(II) Complexes: Rich Variety and Bright Red to Near-Infrared Luminescence with a Large Pseudo-Stokes Shift
Authors: Sakamoto Ryota , Nishihara Hiroshi 
Published: February 2020

Bis(dipyrrinato)metal(II) and tris(dipyrrinato) metal(III) complexes have been regarded as much less useful luminophores than their boron difluoride counterparts (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes, BODIPYs), especially in polar solvent. We proposed previously that dissymmetry in such metal complexes (i.e., two different dipyrrinato ligands in one molecule) improves their fluorescence quantum efficiencies. In this work, we demonstrate the universality and utility of our methodology by synthesizing eight new dissymmetric bis(dipyrrinato)zinc(II) complexes and comparing them with corresponding symmetric complexes. Single-crystal X-ray diffraction analysis, 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry confirm the retention of dissymmetry in both solution and solid states. The dissymmetric complexes all show greater photoluminescence (PL) quantum yields (ΦPL) than the corresponding symmetric complexes, allowing red to near-infrared emissions with large pseudo-Stokes shifts. The best performance achieves a maximum PL wavelength of 671 nm, a pseudo-Stokes shift of 5400 cm−1, and ΦPL of 0.62−0.72 in toluene (dielectric constant εs
= 2.4), dichloromethane (εs
= 9.1), acetone (εs
= 21.4), and ethanol (εs
= 24.3). The large pseudo-Stokes shift is distinctive considering BODIPYs with small Stokes shifts (∼500 cm−1), and the ΦPL values are higher than or comparable to those of BODIPYs fluorescing at similar wavelengths. Electrochemistry and density functional theory calculations illustrate that frontier orbital ordering in the dissymmetric complexes meets the condition for efficient PL proposed in our theory.
Electrochemical Behavior of Aromatic Diamines and the Growth of Conducting Films
Authors: Tsunashima Katsuhiko , Minami Naoki , Ono Yasushi , Imoto Mitsutaka , Mori Seiichi , Takeda Motonori 
Published: February 2020

Aromatic diamine compounds have p-conjugated organic systems based on a phenylene and two amino groups.1 They also have been used commercially as precursors for dyes, pigments, curing agents and high performance polymer materials; however, electrochemistry of the aromatic diamine compounds have not been adequately established, despite the fact that the aromatic diamine compounds contain electrochemically active aniline units in their chemical structures. On the other hand, we have designed and proposed electropolymerization systems of p-conjugated aromatic compounds such as pyrrole, thiophene and aniline in highly conductive ionic liquid media, electrochemically and morphologically characterizing the polymerized conducting films grown on the electrode surface.2 In this work, we report the voltammetric behavior of several aromatic diamine compounds containing a biphenyl framework (Fig. 1), investigating the conducting film formation on the electrode surface.
Four aromatic diamines (Bzd(m-Me)2, Bzd(m-CF3)2, Bzd(o-Me)2 and Bzd(o-OMe)2) were supplied by SEIKA Corporation. The electrooxidative behavior of the aromatic diamine compounds was evaluated by cyclic voltammetry (CV) method using a conventional three-electrode cell equipped with a Pt disk working electrode (0.020 cm2), a Pt wire counter electrode and an Ag/Ag+ reference electrode. A 0.1 mol dm-3 tetrabutylammonium hydrogen sulfate (TBA-HS) / MeCN was used as an electrolytic media for the CV measurement. All electrochemical measurements were carried out under dry argon atmosphere at ambient temperature. The electrical conductivity of the films was estimated by the resistivity measured by a dc 4-prove method.
Fig. 2 depicted the cyclic voltammograms for the electrochemical oxidation of Bzd(m-Me)2 and Bzd(m-CF3)2. It was found that an irreversible oxidation peak was observed in each aromatic diamine compound; however, the oxidation peak of Bzd(m-CF3)2 drastically shifted to the potential region more positive than that of Bzd(m-Me)2 because of the electron withdrowing by the trifluoromethyl group in Bzd(m-CF3)2. It should be noted that no film formation on the working electrode surface was observed in the case of Bzd(m-Me)2 and Bzd(m-CF3)2 whereas both Bzd(o-Me)2 and Bzd(o-OMe)2 significantly formed the films on the electrode surface, giving the relatively large voltammetric responses. From this result the position of the substituents seems likely to play an important role in the film growth. The electrical conductivity of the film formed in the electrochemical oxidation of Bzd(o-OMe)2 was 1.2 S cm-1, which was similar to the conductivity value previously found in the electropolymerized polypyrrole film.2 The electrochemical activity and morphology of the films obtained will be discussed.

References
1. X. –G. Li, M. –R. Huang and W. Duan, Chem. Rev., 102, 2925 (2002).
2. K. Tsunashima, T. Matsubayashi, Y. Ono and M. Matsumiya, ECS Electrochem. Lett., 3, G1 (2014).

Figure 1
Structure-Activity Relationship of AMP-Luciferin Analogs for In Vivo Imaging
Authors: Kitada Nobuo , Iwano Satoshi , Kiyama Masahiro , Saito Ryohei , Hirano Takashi , Niwa Haruki , Maki Shojiro 
Published: February 2020

Firefly bioluminescent system is attracting widespread attention as an in vivo imaging tool. Recently, Near-InfraRed (NIR) light (650~1000 nm) is hot topic due to high living body permeability. Although many NIR fluorescence imaging tools are commercialy available, these are not self-luminescent.
We study the relationship between structure modification and the firefly luminescence wavelength, that the luciferase of Photinus pyralis (Ppy) was used. And we have succeeded in development of Akalumine® which is a world's first near-infrared light in vivo imaging tool of bioluminescence. Akalumine® is employ in vivo imaging for mice. However, we wish Akalumine® is used much bigger animals like a marmoset, miniature pigs for in vivo imaging. Although Akalumine® is useful for in vivo imaging, it is not enough for big animal. We will give a suggestion for solving this problem.
Luminescence of a firefly is two stepwise reactions. Luciferase convert luciferin into AMP-luciferin (intermediate) by adenylation reaction, andthen AMP-luciferin is converted into oxyluciferin by oxygenation reaction. It is known that emission efficiency increase 1000 fold by using the AMP-luciferin, instead of lucifein. So the emission efficiency of luciferin can be raised when AMP-luciferin is used. However, it is very unstable. Then, I will make elaborate AMP-luciferin analogs, and I try to clear practical problem by establishing structure-activity relationship of AMP-luciferin analogs.
I will present the details of this result.

Figure 1
Pd/Uio-66/Ti Electrode for Electrocatalytic Debromination of Tetrabromobisphenol a
Authors: Jiang Fang , Feng Xiangwen , Chen Huan 
Published: February 2020

Metal organic frameworks (MOFs) have engendered great interest due to their high surface areas, tunable porous size, and functionalities. They are explored in a wide range of applications including absorption, gas storage or separation, catalysis, biomedicine and drug delivery. Presently, a large number of reports appraise the application of MOFs in the field of electrochemistry, from rechargeable batteries, supercapacitors to fuel cells. Among these various metal organic frameworks, UiO-66 as a type of highly stable zirconium-based MOF linking by 1,4-benzenedicarboxylate (BDC), has been extensively studied. It is reported that UiO-66 demonstrates high structural stability in water medium, thus, it shall be a feasible strategy to incorporate UiO-66 with other functional materials for the applications in aqueous medium, water treatment and water splitting for instance. Herein, palladium nanoparticles supported UiO-66 was fabricated on Ti plate electrode (Pd/UiO-66/Ti) in this study. White UiO-66, as a bridging layer with controlled size and thickness, was first deposited on Ti plate via an electrochemical film deposition method. UiO-66/Ti plates of different thickness were acquired by changing the ratio of electrochemical deposition solution. Pd/UiO-66/Ti was further made by dipping Pd2+ solution onto the UiO-66 surface and then reduced by impregnating in 0.1 % NaBH4 solution for two hours. The obtained dark Pd/UiO-66/Ti electrode was characterized by X-ray diffraction (XRD). And the electrochemical properties of the Pd/UiO-66/Ti cathode electrode were investigated through cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results revealed that UiO-66 films with different thickness were successfully deposited on the Ti cathodes (UiO-66/Ti), Pd particles well dispersing on the surface of the UiO-66/Ti. The electro-catalytic performance was evaluated by electrocatalytic debromination of 5 mg/L tetrabromobisphenol A (TBBPA) in a 200 mL vessel, containing Pd/UiO-66/Ti as cathode, graphite as anode at a current of 6.67 mA/cm2. It was found that degradation rate of TBBPA was 80% within 60 min by Pd/ UiO-66/Ti cathode electrode. The excellent electro-catalytic performance could be ascribed to the adsorption of TBBPA on UiO-66 and the reaction with hydrogen at the palladium/UiO-66 interface. The results indicated that Pd/UiO-66/Ti should be a promising cathode for the application on electrochemical.
Growth of Transition Metal Nanoclusters to Get Enhanced Catalytic Abilities
Authors: Hussain Tajamal , Ashraf Munazza , Mujahid Adnan , Raza Muhammad Hamid , Shehzad Khurram 
Published: February 2020

Electro deposition is one of the economical and straight forward method to get metal in desired structure and size. In many cases, electro deposition is used in different fashions to have nanostructure. Here, electro deposition was carried out in citrate bath as well as reverse microemulsion. Citrate bath was prepared for different transition metals and these metals were deposited on copper substrate. Metal nanoparticles got deposited by reverse microemulsion method using Triton X-100 as a surfactant. Stable and transparent microemulsion was synthesized at room temperature. After the formation of metal ions in the emulsion, they were reduced at the copper electrode and deposition took place. Reverse micelles provided suitable environment to the metal ions and acted as a template. The electrochemical activity of the electrodes prepared by both methods was compared by carrying out oxidation of alkaline solution and alcohols. It was observed that electrodes modified using reverse micro emulsion as template showed considerable enhanced catalytic abilities than electrodes prepared in citrate bath. Study of surface morphology through scanning electron microscopy indicates the formation of nanoclusters of deposited metals in case of reverse microemulsion. These nanoclusters, nanocatalysts, are mainly responsible for enhanced catalytic abilities.
Electrochemical Synthesis of Single Pt Atom Catalyst for Hydrogen Reactions
Authors: Chen Wei-Fu , Fang Si-Lin , Chen Li-Chyong , Sasaki Kotaro 
Published: February 2020

Single metal atom/center catalysts that bridge heterogeneous and homogeneous catalysis have very recently attracted much attention for the maximum usage of noble metal atom and great potential to achieve high activity and selectivity [1]. Very recently, several techniques have been developed to achieve supported single platinum atom for catalysis on metal oxides including Al2O3 and iron oxides which have a strong interaction with platinum atoms [2,3]. One key issue is that the high surface free energy of metal atom usually induces aggregation of metal atoms into big clusters. These techniques, however, only allow metal atoms prepared on oxide materials. In this study, we investigated the possibility of preparing Pt atoms by using electrochemical deposition techniques and whether the Pt atoms can be deposited on non-oxide materials. The result to the question turned out to be in the affirmative, yielding Pt atoms on carbon materials in addition to metal oxides.
According to the two-electron-reaction models, cathodic hydrogen evolution in acidic aqueous media on bulk Pt proceeds through a two-steps Volmer–Tafel mechanism. First, the discharge step (Volmer reaction); second, the recombination step (Tafel reaction). While on single Pt atoms, we demonstrated that the HER occurs through a Volmer–Heyrovský mechanism, that is, the rate-determining step is the electrochemical desorption of Hads and H3O+ to form hydrogen (Figure 1). The electrocatalytic activities and mechanism of the hydrogen evolution reaction (HER) and hydrogen oxidation reactions (HOR) will be reported.

References

1. Yang, X. F. et al. Accounts Chem. Research
2013, 46, 1740.
2. M. Moses-DeBusk et al. J. Am. Chem. Soc.
2013, 135, 12634.
3. Qiao et al. Nature Chem.
2011, 3, 634-641

Figure 1
(Invited) Ionic Liquid Enables Technologies for Winning Rare Earth Elements
Authors: Mudring Anja-Verena 
Published: February 2020

Rare earth elements are amongst the most critical materials, they are crucial for a number of energy related technologies relying on the superior catalytic, optical or magnetic properties that can be achieved in their compounds.
As catalysts they find application in fluidic catalytic cracking (FCC) catalysis, one of the most important processes in petrochemistry where they are used to convert the high-molecular weight hydrocarbon fraction of crude oil into more useful lower-weight hydrocarbons. Rare earth based phosphors are the key part for energy conversion in compact fluorescent lamps (CFLs) and light emitting diodes (LEDs) which are currently the most important energy efficient lighting devices. As phosphors rare earth based materials find also application in scintillators for radiation detection (as used by Homeland Security) or for medical imaging. As security makers they can be found in passports and banknotes. Currently an increased consumer demand for rare earth materials arises from the increased use of cell phones and tablets. The exceptional properties of rare earth elements are particularly used in alloys for permanent magnets. The properties of SmCo5 and Nd2Fe14B are unsuperseded. Because of their high field strength Nd2Fe14B magnets are used in hard drives, motors for hybrid cars or wind turbines. SmCo5 is less used as it not only has a weaker field strength, but is also more expensive because it contains two critical elements, samarium and cobalt. However, as the Curie temperature of SmCo5 is higher than that of Nd2Fe14B is used in applications where high field strengths at high temperatures are needed.
However, the stable economic supply of rare earth elements is not guaranteed and, thus, the pproduction and use of rare earth compounds constitute an important strategic and dynamic segment of the electronic, chemical and energy industries. The presentation will discuss the importance and criticality of rare earth elements and will give insights into how ionic liquids can provide technology solutions for rare earth recycling, separation and production, most importantly, the electrodeposition from ionic liquids as an alternate, greener process to the currently used high temperature process.
Influence of the Alkaline Earth Metal Cations on the Standard Rate Constants of Charge Transfer for the Redox Couple Ti(IV)/Ti(III) in Chloride-Fluoride Melts
Authors: Vetrova Daria A. , Kuznetsov Sergey A. 
Published: February 2020

The aim of the present investigation was study of charge transfer kinetics for the redox couple Ti(IV)/Ti(III) in the (NaCl-KCl)equimol.-NaF(10 wt.%)-K2TiF6 melt and the estimation of the alkali earth metal cations influence on the standard rate constants of charge transfer (ks
) for this redox couple.
Method of cyclic voltammetry was employed for the determination of the standard rate constants of charge transfer. The electrochemical redox process:
Ti(IV) + e-↔ Ti(III) (1)
was classified as quasi-reversible in the range of scan rate 0.75 V s-1≤ν≤2.0 V s-1. The standard rate constants of charge transfer for the reaction (1) were calculated based on the Nicholson’s equation.
It was shown, that k
s increase with increasing temperature and the temperature dependence of k
swas described by the following empirical equation:
log k
s=(1.505±0,32)–(3364±675)/Т (2)
The activation energy of charge transfer calculated from (2) was found equal to (64.41±13) kJ mol-1.
Influence of strongly polarizing cations of Mg2+, Ca2+, Sr2+ and Ba2+on the standard rate constants of charge transfer for the redox couple Ti(IV)/Ti(III) was studied.
It was determined that addition of alkali earth metal cations resulted in increasing of ks
up to the certain mole ratio of Me2+/Ti(IV), which was inversely proportional to ionic potential of cations. Further addition brought some decreasing of the standard rate constants. Increase of ks
is connected with substitution of Na+ and K+ cations by strongly polarizing cations in the second coordination sphere of titanium complexes that led to increasing of the bond distance between Ti and F- ligands and decreasing of titanium fluoride complexes strength. Decrease of ks
at the definite ratio of components can be explained by increasing of the viscosity melts, which brings to decreasing of the diffusion coefficients.
It was established the linear dependence of ks
on ionic potential of alkali earth metal cations and the maximum value was obtained for complexes with outer sphere cations of magnesium. The temperature dependences for the maximum values of ks
in the melts containing strongly polarizing cations were fitted by empirical equations and the activation energies of charge transfer were calculated. Values of activation energy for systems with strongly polarizing cations are considerably less than activation energy for initial system.
Acknowledgments
The work was financially supported by Russian Foundation for Basic Research (15-03-02290_a).