Search

The consistent and accurate electronic energies and structures for a wide range of compounds with important sulfur containing functional groups are evaluated. Study also provides the choice of methods for a wide range of structurally related species.

Photon statistics of blinking CdSe-ZnS nanocrystals interacting with a continuous wave laser field is analyzed showing that the process is described by a ballistic Levy walk. It is shown that Mandels Q parameter, describing the fluctuations of the photon counts is increasing with time eve in the limit of long time.

Several molecular descriptors based on topological approaches as well as on a more traditional orbital-based decomposition, used to assess relations with hydrogen bond strengths in a series of formic acid dimers and its sulfur derivatives. A study devoted to the description of hydrogen-bond interactions through the use of few molecular descriptors is performed.

Exchange-induced spin polarization in the magnetic semiconductor EuS at room temperature studied by X-ray magnetic-circular-dichroism measurements is reported. An alignment of the Eu moments is denoted at the interface as spin polarization yielding a net EuS Magnetization and this turns Co/EuS multilayers into promising material for spin injection applications.

The effects of structural and surface properties of carbon materials on the adsorption of benzothiophene (BT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) are investigated in the presence of 10 wt % of aromatics in liquid alkanes that simulate sulfur compounds in diesel fuels. The high-adsorption capacity and selectivity for methyl DBTs show that certain activated carbons are promising adsorbents for selective adsorption for removing sulfur (SARS) as a new approach to ultra deep desulfurization of diesel fuels.

Single crystals of Ta4S9Br8 are obtained by heating Ta, S, and Br2 and the structure is determined by X-ray analysis consisting of molecular clusters [Ta4(mu4-S)(mu-S2)4Br8]. The compound is soluble in CH3CN, giving a dark-red solution with a characteristic electronic spectrum, which is assigned on the basis of DFT calculations.

Electronic structures of [Fe2S2(SCH3)4](super 2-, 3-) in DMSO solution are calculated using reference interaction site model complete active space self-consistent field (RISM-CASSCF)/multireference second-order Moller-Plesset perturbation theory (MRMP) method. The effect of solvent environment and its fluctuation is crucial in describing the redox processes of Fe2S2 clusters.

Structural and electronic properties of (100)-oriented MgSO4 and MgSO4.H2O surfaces and the adsorption of water on the latter are investigated theoretically with a combination of ab initio and semiempirical methods. The molecular adsorption of water on the MgSO4.H2O surface leads to only small shifts of the electronic energy levels.

Weak nonbonded interaction between a divalent sulfur (S) atom and a main-chain carbonyl oxygen (O) atom are characterized in proteins. However, they have shown distinctly different directional propensities around the O atom from the S...O interactions in small organic compounds, although the linearity of the C-S...O or S-S...O atomic alignment was observed. The results suggested that S...O interactions may control protein structures to some extent and its unique directional properties can be applied to molecular design.

The preparation of the (Me2N3)S(super +) (TAS)(super 16), (Me2N)(sub 3)SO(super +) (TAOS), N(CH3)(sub 4)(super +) (TMA)(super 3,4), and K(super +) salts of SO(sub 2)F(super -) and their low temperature crystal structures are described. It is shown that the true geometry of SO(sub 2)F(super -) is close to the calculated ones and that the varying degrees of deviation, exhibited in the crystal structures of the different salts, are due to the propensity of SO(sub 2)F(super -) to undergo oxygen/fluorine and in oxygen-site disorders.

A disulfide-bridged dicopper(I) complex, [Cu(sub 2)(Py2SSPy2)](ClO4)(sub 2), synthesized by the redox reaction of a Cu(II) salt with a thiol-containing N3S-donor ligand, N,N-bis[2-(2-pyridyl)ethyl]-2-mercapto-2-methylpropylamine (Py2SH), is demonstrated to catalyze epoxidation and hydroxylation with H2O as an oxidant. The mechanistic studies demonstrate that by virtue of the electron-donating ability of the disulfide unit, the Cu-OOH species can be actually activated for one-electron oxidation, which is reported as unfavorable for other vibrationally characterized Cu-OOH species.

The microwave absorption dielectric-spectrum technique was used to study the decay kinetics of the free photoelectrons and shallow-trapped electrons in the sulfur-sensitized T-grain AgBrI crystals prepared under different sensitization times. The range of the shallow electron trap depth traps was determined to be 0.26-0.27 eV.

The dinuclear gold complexes are prepared and characterized by using X-ray crystallography. The photophysical studies have shown that the participation of intra- and intermolecular Au...Au interactions are relevant to the luminescent properties and the emission spectra are strongly temperature dependent.

A new catalyst design strategy based on optimizing electronic structure was proposed and then applied to the design of selective, sulfur-resistant oxidation emissions catalysts. It was seen that an alloy surface (Ir alloyed Pt(111) surface) with a surface d-band center around -2.22 eV has the highest selectivity for oxidation of NO over SO2 at 700K.

The chemistry of Fe(super IV)aqO(super 2+), its reactivity in oxygen atom transfer reactions, which provide additional evidence for formulation of the species as a pentaaquairon(IV)-oxo complex, Fe(H(sub 2)O)(sub 5)O(super 2+) is explored. The Fe(super IV)aqO(super 2+)/ sulfide reaction is the product-forming step in a very efficient Fe(sub aq)(super 2+)-catalyzed oxidation of sulfoxides by ozone.

The kinetic and structural properties of a series of disulfide mutants engineered into the sequence of pig pancreatic IB 14 kDa phospholipase A2 (PLA2) to resemble the mammalian paralogues of the PLA2 family are analyzed. The results show that the disulfide architecture has a significant effect on the calcium binding and the associated active site events without displaying a significant effect on the functions of the interface-binding region of PLA2.

A study was conducted to investigate the reaction mechanism of O + COS -> products. Time-resolved measurements of O and S atoms were conducted by using atomic resonance absorption spectroscopy, and the overall rate constant was determined by the O atom decay at temperatures 1250-1600 K.

It is reported that disulfur ligands bridging two metal atoms have three possible coordination modes: (n(super 1), n(super 1)), (n(super 1), n(super 2), and (n(super 2), n(super 2). Chemical and electrochemical redox are studied in pursuit of a more general view for such redox-associated behavior of disulfide ligands.

The synthesis of high symmetric 18-facet polyhedron of nanocrystalline Cu7S4 with regular hollow structure based on the Kirkendall Effect and converted it from cubic cuprous oxide nanocrystals is described. The results show that the crystal structure changes from cubic to monoclinic when converted from Cu2O to Cu7S4.