Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

Complex Hydrides for Hydrogen Storage

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

The storage of electric energy is of ever growing importance for our modern, technology-based society, and novel battery systems are in the focus of research. The substitution of conventional metals as redox-active material by organic materials offers a promising alternative for the next generation of rechargeable batteries since these organic batteries are excelling in charging speed and cycling stability. This review provides a comprehensive overview of these systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes. Moreover, a definition of important cell characteristics and an introduction to selected characterization techniques is provided, completed by the discussion of potential socio-economic impacts.

Polymer-Based Organic Batteries

A Calculation of Atomic Structures. By D. R. Hartree Pp. xiii, 181. 40s. 1957. (Wiley, New York)

The review focuses on various hydrogen producing and storing methods that can be employed for creating a hydrogen economy. The latest advancements that have been made on different hydrogen storing materials and hydrogen storing technologies which have proven useful both on gravimetric and volumetric basis, have been highlighted. The encouraging and hopeful aspect of their developments is that the most of the materials are approaching the hydrogen storing capacity requirement that have been laid down by DOE. The classification of different systems has been done on basis of their storage mechanism, keeping in mind their advantages and disadvantages while they tend to store hydrogen both in the atomic and molecular form.

Hydrogen storage: Materials, methods and perspectives

A simple descriptor, viz the number of carbon (N C )/non-hydrogenic (N NH ) atoms present in a molecule, is proposed for the development of useful Quantitative Structure-Property-Relationship (QSPR) models. This work is prompted by that of Randic and Basak (J. Chem. Inf. Comput. Sci.2001, 41, 614-618) who have shown that this descriptor is superior to the simple connectivity index and is marginally worse than the variable connectivity index for analyzing the toxicity of aliphatic ethers. It is tested in the present work in models pertaining to the estimation of boiling point of alcohols, enthalpy of vaporization of Polychlorinated Biphenyls (PCBs), n-octanol/water partition coefficient of PCBs and chloroanisoles, pK a values of carboxylic acids, phenols, alcohols, etc. High values of various regression coefficients (R 2 , R 2 CV , R 2 AD ) suggest the significance of this descriptor which further improves in the resulting two-parameter QSPR models with electrophilicity or its local variant as an additional descriptor. Other statistical quantities are also analyzed for gaining additional insights into the proposed models. Although the atom number is not the best possible descriptor in a QSPR model in all cases, its simplicity provides it a special place in the development of those models. The present analysis extends the work of Randic and Basak by delineating the situations when N C /N NH performs well vis-a-vis the other descriptors.

An Atom Counting QSPR Protocol

Charge‐based DFT descriptors for Diels‐Alder reactions

Geometries of several all-metal clusters with Zn32− as the base are optimized within a B3LYP/6-311+G(d) level of theory. It is analyzed that the stability, bonding, reactivity and aromaticity patterns of such clusters often change drastically in the presence of counter cations like Li+, Na+ or K+ and/or through the substitution of Zn32− units by Be5− or C5H5− rings.

Structure, bonding, reactivity and aromaticity of some selected Zn-clusters

Catalyst electronic polarizability and enantiomeric excess in asymmetric hydrogenation

The atomic number (Z) and electrophilicity index (ω) have been utilized to explain the toxicity of various alkali and transition-metal ions as well as to predict that of the arsenic ions. The toxicity of two different training sets of arsenic derivatives is described using the global electrophilicity (ω) and number of nonhydrogenic atoms (N
 NH) along with the local philicity $${(\omega _{\rm As}^+)}$$
 and the atomic charge (Q
 As) on the arsenic atom. Applying the regression models from the training sets, toxicity of some unknown arsenic derivatives is predicted.

Santanab Giri

Papers

An Atom Counting QSPR Protocol

Charge‐based DFT descriptors for Diels‐Alder reactions

Structure, bonding, reactivity and aromaticity of some selected Zn-clusters

Catalyst electronic polarizability and enantiomeric excess in asymmetric hydrogenation

Arsenic toxicity: an atom counting and electrophilicity-based protocol.