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Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry

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https://www.readbyqxmd.com/read/28636148/magneto-structural-characterization-of-oxalamide-dihalo-bridged-copper-dimers-intra-and-interdimer-interactions-studied-by-single-crystal-esr-spectroscopy
#1
Dijana Zilic, Debdeep Maity, Mario Cetina, Kresimir Molcanov, Zoran Dzolic, Mirta Herak
The detailed single crystal electron spin resonance (ESR) analysis of oxalamide complexes with halogen-bridged copper dimers, supported by X-ray, magnetic susceptibility and powder ESR studies, is reported. Four complexes with two different ligands were synthesized: [CuLA(μ-X)]₂ and [CuLV(μ-X)]₂, where LA = N-(L-alanine methyl ester)-N'-((2-pyridine-2-yl)methyl)oxalamide and LV=N-(L-valine methyl ester)-N'-((2-pyridine-2-yl)methyl)oxalamide, while X=Cl or Br. X-ray analysis shows that geometry at each copper(II) ion is square pyramidal while two pyramids share one base-to-apex edge with parallel basal planes...
June 21, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28632959/defect-based-modulation-of-opto-electronic-properties-for-bio-functionalized-hexagonal-boron-nitride-nanosheets
#2
Mehdi Shakourian-Fard, Hadiseh Heydari, Ganesh Kamath
Defect engineering could potentially allow for dramatic tuning of optoelectronic properties of two-dimensional materials. With the help of density functional theory (DFT) calculations, we present a systematic study of the DNA Nucleobases (NBs) adsorbed on hexagonal boron-nitride nanoflake (h-BNNF) and boron and nitrogen monovacancies. The presence of such VN and VB defects increases the binding strength of NBs by 9 kcal/mol and 34 kcal/mol, respectively (h-BNNF-VB> h-BNNF-VN> h-BNNF). A more negative electrostatic potential at the B vacancy-site makes h-BNNF-VB surface more reactive than h-BNNF-VN surface enabling H-bonding interactions with NBs...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28631872/formation-of-bifeo3-from-a-binary-oxide-superlattice-grown-by-atomic-layer-deposition
#3
Aleksandr V Plokhikh, Matthias Falmbigl, Iryna S Golovina, Andrew R Akbashev, Igor A Karateev, Mikhail Y Presnyakov, Alexander L Vasiliev, Jonathan E Spanier
We report on the growth of polycrystalline BiFeO3 thin films on SiO2 /Si(001) and Pt(111) substrates by atomic layer deposition using the precursors ferrocene, triphenyl-bismuth, and ozone. By growing alternating layers of Fe2 O3 and Bi2 O3 , we employ a superlattice approach and demonstrate an efficient control of the cation stoichiometry. The superlattice decay and the resulting formation of polycrystalline BiFeO3 films are studied by in situ X-ray diffraction, in situ X-ray photoelectron spectroscopy, and transmission electron microscopy...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28631865/chemical-communication-between-molecules
#4
REVIEW
Patricia Remón, Uwe Pischel
In this Minireview conceptual approaches towards the communication between (supra)molecular species are illustrated. The reviewed mechanisms include photophysical communication through energy transfer and communication mediated by chemical species that are released from precursors upon application of an external stimulus. The focus is on the stimulation by (reversible) photoreactions. Special attention has been given to supramolecular systems that illustrate the idea of chemical communication and information transfer in a very descriptive manner...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28631384/nmr-study-of-the-reductive-decomposition-of-bmim-ntf2-at-gold-electrodes-and-indirect-electrochemical-conversion-of-co2
#5
Roman Michez, Thomas Doneux, Claudine Buess-Herman, Michel Luhmer
Potential controlled electrolyses of [BMIm][NTf2 ] ionic liquid were performed at a gold cathode under nitrogen atmosphere. The structures of the major conversion products of the BMIm(+) cation were elucidated on the basis of 1D and 2D nuclear magnetic resonance (NMR) analyses and gas chromatography (GC) analysis of the volatile compounds. Recombination of the imidazol-2-yl radicals, generated at the electrode by single electron transfer, leads to neutral diastereomeric dimers in equal proportions, with a faradaic efficiency of 80 %, while disproportionation of these radicals and/or reaction with hydrogen atoms adsorbed at the electrode generates a neutral monomer with 20 % faradaic efficiency...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28627806/improving-the-quantum-yields-of-perylene-diimide-aggregates-by-increasing-molecular-hydrophobicity-in-polar-media
#6
Jodi Szarko, Jürgen Plenge, Xiaoyu Xu, Ashli Austin, Steven Mylon
Here we report the quantum yield of four aggregated perylene diimide (PDI) species that vary by the length of the branched side chains attached at the N,N' imide positions. The PDI molecules were dissolved in binary water:methanol solvents as a means to vary the solvent polarity and control the degree of aggregation in solution. By performing spectroscopy, kinetics, and light scattering experiments, the nature of the molecular interactions in the solutions was determined. The maximum quantum yield of the aggregated molecules increased from 0...
June 19, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28627744/femtosecond-charge-injection-dynamics-at-hybrid-perovskite-interfaces
#7
Giulia Grancini, Daniele Viola, Yonghui Lee, Michael Saliba, Sanghyun Paek, Kyung Taek Cho, Simonetta Orlandi, Marco Cavazzini, Fernando Fungo, Mohammad I Hossain, Abdelhak Belaidi, Nouar Tabet, Gianluca Pozzi, Giulio Cerullo, Mohammad Khaja Khaja Nazeeruddin
With power conversion efficiency (PCE) exceeding 22%, perovskite solar cells (PSCs) have thrilled the photovoltaic research. However, interface behavior is still not understood and a hot subject of research: different processes occur over a hierarchy of timescales, from femtoseconds to seconds, making the perovskite interface physics intriguing. Here, by femtosecond transient absorption spectroscopy with spectral coverage extended to the crucial IR region, we interrogate the ultrafast interface- specific processes at standard as well as newly molecularly-engineered perovskite interfaces used in state of the art PSCs...
June 19, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28618080/electrocatalytic-mechanism-involving-michaelis-menten-kinetics-at-the-preparative-scale-theory-and-applicability-to-photocurrents-from-photosynthetic-algae-suspension-with-quinones
#8
Guillaume Longatte, Manon Guille-Collignon, Frédéric Lemaître
In the past years, many strategies were implemented to take benefits from oxygenic photosynthesis to harvest photosynthetic electrons and produce a significant photocurrent. Therefore, electrochemical tools were considered and globally relied on the electron transfer(s) between the photosynthetic chain and a collecting electrode. In this context, we recently reported the implementation of an electrochemical set-up at the preparative scale to produce photocurrents from a Chlamydomonas reinhardtii algae suspension with an appropriate mediator (2,6-DCBQ) and a carbon gauze as the working electrode...
June 15, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28612471/metal-cations-induced-%C3%AE-%C3%AE-bchl-a-heterogeneity-in-lh1-as-revealed-by-temperature-dependent-fluorescence-splitting
#9
Fei Ma, Long-Jiang Yu, Manuel J Llansola-Portoles, Bruno Robert, Zheng-Yu Wang-Otomo, Rienk van Grondelle
Two spectral forms of the core light-harvesting complex (LH1) of the purple bacterium Thermochromatium (Tch.) tepidum, native Ca2+-binding and Ba2+-substituted one, exhibit different fluorescence (FL) emission spectra at low temperature. While Ca-LH1 exhibits one emission band, an unusual splitting of the fluorescence is observed for Ba-LH1. These two sub-bands display the same spectral width dependence according to temperature, but their intensity evolutions with the temperature are different. Based on the crystal structures, we propose that the FL splitting originates from a large αβ-BChl a transition energy heterogeneity, ~600 cm-1, actually much larger than usually in other LH1 and LH2 complexes (80-200 cm-1)...
June 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28609571/p-containing-polycyclic-aromatic-hydrocarbons
#10
Rózsa Szűcs, Pierre-Antoine Bouit, Laszlo Nyulászi, Muriel Hissler
Polycyclic Aromatic Hydrocarbons (PAHs) are highly appealing functional materials in the field of molecular electronics. In particular, molecular engineering of these derivatives using organic chemistry is a powerful method to tune their properties from the point of view of the bandgap and supramolecular assemblies. Another way to achieve such control is to take advantage of the specific reactivity of heteroatoms placed within the C-sp2 framework. This strategy has been successfully applied to N, S or B atoms...
June 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28608640/using-voltammetry-to-measure-the-relative-hydrogen-bonding-strengths-of-pyridine-and-its-derivatives-in-acetonitrile
#11
Malcolm Tessensohn, Yu Rong Koh, Sihao Lim, Hajime Hirao, Richard Webster
The voltammetric behavior of 2,3,5,6-tetramethyl-1,4-phenylenediamine was found to be able to differentiate the hydrogen acceptor abilities of electroinactive pyridine compounds in acetonitrile. Weak and strong hydrogen acceptors were distinguished through the onset of a third oxidation process that came about at sub-stoichiometric amounts of strong hydrogen acceptors, but not in the presence of weak hydrogen acceptors. This additional oxidation reaction occurred at a potential between the two 1e--oxidation reactions that phenylenediamines typically undergo (i...
June 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28608625/computing-in-verotoxin
#12
Andrew Adamatzky
We develop an excitable automata model of a protein verotoxin and demonstrate that logic gates and circuits are realised in the model via interacting patterns of excitation. By sampling potential input pairs of nodes, we calculate frequencies of logic gates which occurred in the verotoxin model for various parameters of node excitation rules. We show that overall the gates can be arranged in the following hierarchy of descending frequencies: AND>OR>AND-NOT>XOR. We demonstrate realisations of one-bit half-adder and controlled-not gates and estimate memory capacity of the verotoxin molecule...
June 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28605574/selection-of-a-single-isotope-of-multiply-charged-xenon-a-xe-z-a-128-136-z-1-6-by-using-a-bradbury-nielsen-ion-gate
#13
Akihiro Kitashoji, Taiki Yoshikawa, Akimasa Fujihara, Takaaki Kamamori, Shigeki Nashima, Tomoyuki Yatsuhashi
The inclusion of an ion gate in a tandem mass spectrometer allows a specific precursor ion to be selected, and the fragment ions are then used for structure analysis and to investigate chemical reactions. However, the performance of an ion gate has been judged simply by whether or not the target ion was selected. In this study, we designed, manufactured, constructed, and characterized a Bradbury-Nielsen ion gate (BNG). The actual ion selection ability, i.e. the gate function, of the BNG was measured for isotopes of Xe(z+) (z=1-6)...
June 12, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28605155/tio2-anatase-solutions-for-electron-transporting-layers-in-organic-photovoltaic
#14
Moustafa El Kass, Brohan Luc, Nicolas Gautier, Solène Béchu, Céline David, Noëlla Lemaitre, Solenn Berson, M Richard-Plouet
Using reflux method with [Ti8O12(H2O)24]Cl8.HCl.7H2O as titanium precursor at 120°C for 24h leads to produce a transparent colloidal solution of nanosized crystallised anatase TiO2. The adjustment of the particle size and composition of the dispersant is monitored through the initial water content while controlling the conversion of propylene carbonate into propylene glycol occuring during reflux. The solutions were processed as thin films in order to produce electron transporting layers in hybrid bulk heterojunction solar cells, using a blend of P3HT-PCBM polymers as absorbers, in inverted architecture...
June 12, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28605152/in-situ-industrial-bimetallic-catalyst-characterisation-using-scanning-transmission-electron-microscopy-and-x-ray-absorption-spectroscopy-at-one-atmosphere-and-elevated-temperature
#15
Eric Prestat, Matthew Kulzick, Paul Dietrich, Matt Smith, Eu Pin Tien, Grace Burke, Sarah Jane Haigh, Nestor Zaluzec
We have developed a new experimental platform for in situ scanning transmission electron microscope (STEM) energy dispersive X-ray spectroscopy (EDS) which allows real time, nanoscale, elemental and structural changes to be studied at elevated temperature (up to 1000°C) and pressure (up to 1 atm). Here we demonstrate the first application of this approach to understand complex structural changes occurring during reduction of a bimetallic catalyst, PdCu supported on TiO2, synthesized by wet impregnation. We reveal a heterogeneous evolution of nanoparticle size, particle distribution and composition with large differences in reduction behavior for the two metals...
June 12, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28605107/molecular-logic-from-single-logic-gates-to-sophisticated-logic-circuits-from-fundamental-science-to-practical-applications
#16
EDITORIAL
Engin Umut Akkaya, Evgeny Katz, Uwe Pischel
No abstract text is available yet for this article.
June 12, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28599086/in-silico-design-of-dnp-polarizing-agents-can-current-dinitroxides-be-improved
#17
Frédéric A Perras, Aaron D Sadow, Marek Pruski
Numerical calculations of enhancement factors offered by dynamic nuclear polarization in solids under magic angle spinning (DNP-MAS) were performed to determine the optimal EPR parameters for a dinitroxide polarizing agent. We found that the DNP performance of a biradical is more tolerant to the relative orientation of the two nitroxide moieties than previously thought. Generally, any condition in which the gyy tensor components of both radicals are perpendicular to one another is expected to have near-optimal DNP performance...
June 9, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28599084/on-the-importance-of-nonbonding-donor-acceptor-interactions-involving-po2-radical-an-ab-initio-study
#18
Antonio Frontera, Antonio Bauza
In this study several σ-type and π-hole bonding complexes between PO2· radical and electron rich entities have been optimized at the RI-MP2/aug-cc-pVQZ level of theory. We have used Cl-, Br-, I- anions, and ethene, ethyne, HCN, HF and H2O as Lewis Bases. In addition, we have performed NBO and Mulliken spin density analyses, highlighting the donor-acceptor nature of the interaction. Moreover, an interesting retro-donation from the single electron lone pair of the PO2· radical to the Lewis base also contributes to the stabilization of the complexes studied herein...
June 9, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28590586/beyond-the-hammett-effect-using-strain-to-alter-the-landscape-of-electrochemical-potentials
#19
Matthew D Casselman, Corrine F Elliott, Subrahmanyam Modekrutti, Peter L Zhang, Sean R Parkin, Chad Risko, Susan A Odom
The substitution of sterically bulky groups at precise locations along the periphery of fused-ring aromatic systems is demonstrated to increase electrochemical oxidation potentials by preventing relaxation events in the oxidized state. Phenothiazines, which undergo significant geometric relaxation upon oxidation, are used as fused-ring models to showcase that electron-donating methyl groups, which would generally be expected to lower oxidation potential, can lead to increased oxidation potentials when used as the steric drivers...
June 7, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28590077/-electro-chemical-oxidation-of-6-13-bis-tri-isopropyl-silylethynyl-pentacene-to-its-radical-cation-and-dication
#20
Simon Schundelmeier, Bernd Speiser, Holger F Bettinger, Ralf Einholz
6,13-Bis(tri(isopropyl)silylethynyl)pentacene is a prototypical molecule for organic semiconductor and photovoltaic materials making its electrochemical (redox) properties highly interesting. However, previous cyclic voltammetric studies provide only limited information. Kinetic and persistence information, identification of the oxidation product(s) and their further reaction or oxidation have not been reported. Thus, an extended electrochemical and spectroscopic investigation of this compound is conducted in CH2Cl2 and THF electrolytes at Pt electrodes...
June 7, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
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