Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
The following papers are very important in the opinion of two referees. They will be published as soon as possible.
Angle-Resolved Strong-Field Ionization of Polyatomic Molecules: More than the Orbitals Matters
Oumarou Njoya, Spiridoula Matsika and Thomas Weinacht
Strong-field ionization plays a critical role in attosecond pulse generation and molecular imaging. It has been shown to be sensitive to the shape of molecular orbitals, and can therefore be used as a tool for studying time-dependent changes to molecular structure. Using a pump-probe scheme to initiate and capture excited-state dynamics, the authors discuss three molecules whose orbital structures are the same but whose angle and time-dependent yields differ significantly. This suggests that the angle dependence of strong-field molecular ionization is sensitive to more than the shape of the molecular orbital from which an electron is removed.
Received December 14, 2012, published online March 20, 2013, DOI: 10.1002/cphc.201201045 – read now.
A Chemical Lift-Off Process: Removing Non-Specific Adsorption in an Electrochemical Epstein-Barr Virus Immunoassay
Lutz Stratmann, Magdalena Gebala, Wolfgang Schuhmann*
The detection limits of immunoassays and biosensors are often limited by the non-specific adsorption of proteins in complex samples. By forming a self-assembled monolayer, which can be locally chemically activated using scanning electrochemical microscopy, an Epstein-Barr virus immunoassay with amplified electrochemical readout was developed. The monolayer additionally comprises a sacrificial layer which can be removed by acid hydrolysis leading to a chemical lift-off of non-specifically adsorbed species in analogy to the lift-off techniques in photolithography.
Received January 11, 2013, published online May 16, 2013, DOI: 10.1002/cphc.201300029 – read now.
Optimization of a Membraneless Glucose/Oxygen Enzymatic Biofuel Cell Based on a Bioanode with High Coulombic Efficiency and Current Density
Lo Gorton*, Minling Shao, Muhammad Nadeem Zafar, Magnus Falk, Roland Ludwig, Christoph Sygmund, Clemens K. Peterbauer, Dmitrii A. Guschin, Dónal Leech, Sergey Shleev, Wolfgang Schuhmann
The columbic efficiency of enzymatic bioanodes is very important. Bioanodes based on one glucose redox enzyme have low efficiency, extracting only two electrons per glucose. In contrast, biocathodes based on multicopper oxidases are 100% efficient, since they reduce O2 directly to H2O. For ex vivo biodevices (on a tooth, on skin, or on a contact lens), complete oxidation of glucose is crucial. Saliva and tears contain a very low glucose concentration (approx. 0.1 mM) compared to 5 mM in blood. Also, the amount of glucose is limited in the low volume of saliva, sweat or tears. In tears, it is about 10 μL with a flow rate of about 1 μL per min. Thus, the total amount of glucose in tears is only 10-9 M with an addition of 10-10 M per min. Complete bioelectrooxidation of glucose by biofuel cells is obviously needed to design useful biodevices.
Received January 15, 2013, published online April 08, 2013, DOI: 10.1002/cphc.201300046 – read now.
Electrochemically Actuated Stop-Go Valves for Capillary Force-Operated Diagnostic Microsystems
Ioanis Katakis, Alemayehu P. Washe, Pablo Lozano Sanchez, and Diego Bejarano-Nosas
Microchannels containing sequential detection sites for the quantification of analytes and the quality control of reagents are the simplest immunosensing devices if they incorporate a flow control for reagent dissolution and incubation. This can be achieved by printing pairs of superhydrophobic electrodes transversal to the capillary flow direction. Low potentials activate the flow allowing stop/go steps. Since the structural elements, the flow-control device, and the sensors can all be produced by screen printing, and all the operations can be actuated by a portable potentiostat, this work could be an important step towards the development of quantitative, low-cost, easy-to-use diagnostic devices.
Received January 15, 2013, published online April 16, 2013, DOI: 10.1002/cphc.201300042 – read now.
Integrated Devices to Simultaneously Realize Energy Conversion and Storage
H.S. Peng, Tao Chen, and Zhibin Yang
Other forms of energy are generally converted into electric energy and then stored in electrochemical devices through external electric wires. Peng and colleagues describe novel integrated energy devices that simultaneously realize energy conversion and storage. Both planar and wire architectures are carefully illustrated with an emphasis on the “energy wire”. The wire structure enables unique and promising applications; for example, such wires can be woven into clothes or other complex flexible equipments by using a conventional textile technology.
Received January 13, 2013, published online April 05, 2013, DOI: 10.1002/cphc.201300032 – read now.
Visible-Light-Active Elemental Photocatalysts
Hui-Ming Cheng,* Gang Liu, Ping Niu
Elemental semiconductors are emerging as a fascinating class of photocatalysts for solar-energy conversion. The elemental photocatalysts investigated so far (i.e. Si, Se, P and S) have promising applications in photoelectrochemical water splitting and the photodegradation of organic pollutants. Elemental photocatalysts are still in their infancy, which leaves a huge room for developing them. By applying strategies that are widely used for compound-based photocatalysts, and other special strategies, the activity of elemental photocatalysts can be significantly improved.
Received December 21, 2012, published online February 18, 2013, DOI: 10.1002/cphc.201201075 – read now.
Understanding the Photophysics of Cucurbituril Encapsulation: A Model Study with Acridine Orange in the Gas Phase
Rebecca Jockusch,* Martin F. Czar
A combination of laser-induced fluorescence and mass spectrometry was employed to study the polarizability-sensing dye cationic acridine orange (AOH+) and its host-guest complex with the macrocycle cucurbituril (CB7) in the gas phase. Spectral and time-resolved fluorescence measurements of gaseous AOH+ and AOH+-CB7 are presented and compared with aqueous-phase measurements to gain insight into how CB7 binding modulates the fluorescence properties of AOH+. The authors discuss the relative importance of dye desolvation and CB7 encapsulation in terms of their effects on various spectroscopic properties of AOH+, including the fluorescence excitation maximum, the magnitude of the Stokes shift, and the fluorescence lifetime of the dye.
Received December 03, 2012, published online February 25, 2013, DOI: 10.1002/cphc.201201008 – read now.
Trajectory-Based Nonadiabatic Dynamics with Time-Dependent Density Functional Theory
Basile F. E. Curchod, Ursula Rothlisberger, Ivano Tavernelli*
The description of radiationless photochemical and photophysical processes using first-principles quantum molecular dynamics calculations is a challenging problem because of the breakdown of the Born-Oppenheimer approximation and the difficulty to obtain an accurate description of the required electronic-structure properties.
This review describes, in full detail, a selection of trajectory-based nonadiabatic dynamics schemes within a common framework, and shows how to couple them with time-dependent density functional theory to perform on-the-fly excited-state dynamics.
Received November 15, 2012, published online April 29, 2013, DOI: 10.1002/cphc.201200941 – read now.
MP2.5 and MP2.X: Approaching CCSD(T) Quality Description of Noncovalent Interaction at the Cost of Single CCSD Iteration
Robert Sedlak,* Kevin E. Riley, Jan Řezáč, Michal Pitoňák, and Pavel Hobza*
The accurate computational description of noncovalent interactions requires a high-order treatment of the electron correlation; it is known that MP2 does not yield reliable results. The next most efficient approach, MP3, is not better, but the results improve dramatically when the third-order contribution is scaled down. In the MP2.5 method, one half of the MP3 correlation energy is taken while in MP2.X, the scaling coefficient is optimized for each basis set used. We show that for a wide range of noncovalent complexes, these methods provide interaction energies and geometries with the same accuracy as higher-level and more computationally demanding methods.
Received October 11, 2012, published online January 11, 2013, DOI: 10.1002/cphc.201200850 – read now.
Threshold Collision-Induced Dissociation of Hydrated Magnesium: Experimental and Theoretical Investigation of the Binding Energies for Mg2+(H2O)x complexes (x=2–10)
Damon R. Carl and P. B. Armentrout*
The sequential hydration energies of Mg2+(H2O)x complexes, where x=2–10, including the first experimental values for the inner-shell x=2–4 complexes, are measured by threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer. Additionally, the thermodynamic onsets leading to the charge-separation products, MgOH+(H2O)x-2+H3O+, from Mg2+(H2O)3 and Mg2+(H2O)4, are determined for the first time. The experimental hydration energies are in generally good agreement with quantum chemical calculations performed here and in the literature.
Received October 15, 2012, published online December 12, 2012, DOI: 10.1002/cphc.201200860 – read now.
Laser Spectroscopic Study of Cold Host-Guest Complexes of Crown Ethers in the Gas Phase
Yoshiya Inokuchi, Ryoji Kusaka, Takayuki Ebata*, Oleg V. Boyarkin, Thomas R. Rizzo*
The structures of cold, host-guest complexes of crown ethers (CEs) with various neutral and ionic species formed in the gas phase have been investigated. The combination of laser spectroscopy and theoretical analysis provides a microscopic view of the complex structures as well as the interaction energies. This work highlights the particular importance of the CE flexibility for the formation of a unique complex, which leads to molecular recognition.
Received September 12, 2012, published online November 30, 2012, DOI: 10.1002/cphc.201200746 – read now.
Silicon Nanocrystal Superlattices
Brian Korgel,* Yixuan Yu, Christian A. Bosoy, Colin M. Hessel, Detlef-M. Smilgies
Superlattices of colloidal silicon quantum dots have been made for the first time, enabled by new methods to obtain monodisperse organic ligand-stabilized nanocrystals. Silicon is the most commercially important semiconductor, used in a wide range of applications from solar cells to computer chips. Nonetheless, silicon has shortcomings: it is a weak light absorber and extremely poor light emitter. These properties change when the crystal shrinks to the nanoscale. Silicon quantum dots, for example, can exhibit very bright visible luminescence with size-tunable color. Ordered superlattices of silicon quantum dots will provide an interesting new platform to study and implement these unique properties.
Received September 10, 2012, published online November 22, 2012, DOI: 10.1002/cphc.201200738 – read now.
Towards a Spectroscopic and Theoretical Identification of the Isolated Building Blocks of the Benzene-Acetylene Cocrystal
Markus Böning,* Benjamin Stuhlmann, Gernot Engler, Matthias Busker, Thomas Häber, Adem Tekin, Georg Jansen, Karl Kleinermanns
The structural assignment of large benzene-acetylene clusters is achieved by comparison of isomer- and mass-selective UV and IR/UV double-resonance spectra with quantum chemical calculations. A stepwise aggregation of the clusters is predicted, and a possible cluster-formation pathway is discussed.
Received August 25, 2012, published online November 26, 2012, DOI: 10.1002/cphc.201200701 – read now.
Polariton Dynamics under Strong Light-Molecule Coupling
Thomas Ebbesen,* Tal Schwartz, James A. Hutchison, Jérémie Léonard, Cyriaque Genet, Stefan Haacke
The generation of hybrid light-matter states opens an unusual path to modify and tailor the properties of molecules and materials. Such hybrid states, formed by the resonant interaction between light and molecules, are expected to have a lifetime that is not longer than that of the shortest lived member involved in the interaction (in this case, the cavity photon). In their contribution, T. Ebbesen and co-workers demonstrate that when such hybrid states involve a larger number of molecules in a collective state (resulting in a great energy-level reorganization), the hybrid-state lifetime can be surprisingly long. This is of fundamental importance and has strong impact on the potential applications of strong light-matter interactions.
Received September 08, 2012, published online December 11, 2012, DOI: 10.1002/cphc.201200734 – read now.
Mechanistic Studies on the Transformation of Ethanol into Ethene over Fe-ZSM-5 Zeolite
Jumras Limtrakul,* Thana Maihom, Pipat Khongpracha, Jakkapan Sirijaraensre
The transformation of ethanol, a low-cost biomass product, into fine chemicals is an important process for the development of clean technologies for the chemical industry. The reaction mechanisms of ethanol transformation over an iron exchange zeolite are unraveled by means of quantum chemical calculations -and the possible pathways along a reaction coordinate are discussed and analyzed. The important role of the zeolite framework in lowering the activation barriers and stabilizing the adsorption species is also demonstrated. These results are important for understanding the chemistry of ethanol transformation in detail.
Received September 24, 2012, published online November 19, 2012, DOI: 10.1002/cphc.201200786 – read now.
Photoionization Study of Yb(NH3)n Complexes
Andrew Ellis,* M. J. Guttridge, S. H. Don
Complexes of an Yb atom with multiple NH3 molecules in the gas phase have been investigated for the first time. The ionization energies of the complexes as a function of the number of NH3 molecules have been measured and show a behavior analogous to that of alkali metals. This is consistent with a metal that can release an electron into the solvent, yielding a solvated electron when sufficient NH3 molecules are present. The ionization energies also reveal that Yb can accommodate eight NH3 molecules in its first solvation shell, a finding consistent with supporting ab initio calculations.
Received August 23, 2012, published online October 22, 2012, DOI: 10.1002/cphc.201200691 – read now.
Matrix Isolation Vibrational Circular Dichroism Spectroscopy of 3-Butyn-2-ol and Its Binary Aggregates
Christian Merten, Yunjie Xu*
While vibrational circular dichroism (VCD) spectroscopy shows unique specificity to chirality and is highly sensitive to the conformational equilibria of chiral molecules, the matrix isolation (MI) technique offers narrow spectral bandwidth and sample manipulation. The combination of the two is, however, challenging due to the much smaller VCD signal intensity compared to that of regular infrared absorption. Using the example of 3-butyn-2-ol, Merten and Xu show that MI-VCD is a powerful tool to study self-aggregation, chirality transfer, and other exotic chiral species that can be prepared in a cold matrix.
Received September 14, 2012, published online October 25, 2012, DOI: 10.1002/cphc.201200758 – read now.
Self-Assembled Monolayers with Dynamicity Stemming from (Bio)Chemical Conversions: From Construction to Applications
Inseong Choi and Woon-Seok Yeo*
Surfaces with ‘dynamicity’ stemming from (bio)chemical conversions have been actively developed and harnessed in many research areas. The dynamic surfaces are constructed on numerous materials and activated by various external stimuli. Yeo and Choi focus on self-assembled monolayers (SAMs) as a scaffold and dynamicities that are attributed to (bio)chemical conversions on surfaces. The authors also categorize the dynamic SAMs from the perspective of chemical reactions.
Received April 03, 2012, published online June 14, 2012, DOI: 10.1002/cphc.201200293 – read now.