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991.
Donato Ercole Conte Abdelmaula Aboulaich Josette Olivier-Fourcade Christian Jordy 《Journal of solid state chemistry》2010,183(1):65-6650
A comparative study of two Sn-based composite materials as negative electrode for Li-ion accumulators is presented. The former SnB0.6P0.4O2.9 obtained by in-situ dispersion of SnO in an oxide matrix is shown to be an amorphous tin composite oxide (ATCO). The latter Sn0.72[BPO4]0.28 obtained by ex-situ dispersion of Sn in a borophosphate matrix consists of Sn particles embedded in a crystalline BPO4 matrix. The electrochemical responses of ATCO and Sn0.72[BPO4]0.28 composite in galvanostatic mode show reversible capacities of about 450 and 530 mAh g−1, respectively, with different irreversible capacities (60% and 29%). Analysis of these composite materials by 119Sn Mössbauer spectroscopy in transmission (TMS) and emission (CEMS) modes confirms that ATCO is an amorphous SnII composite oxide and shows that in the case of Sn0.72[BPO4]0.28, the surface of the tin clusters is mainly formed by SnII in an amorphous interface whereas the bulk of the clusters is mainly formed by Sn0. The determination of the recoilless free fractions f (Lamb-Mössbauer factors) leads to the effective fraction of both Sn0 and SnII species in such composites. The influence of chemical composition and especially of the surface-to-bulk tin species ratio on the electrochemical behaviour has been analysed for several Snx[BPO4]1−x composite materials (0.17<x<0.91). The cell using the compound Sn0.72[BPO4]0.28 as active material exhibits interesting electrochemical performances (reversible capacity of 500 mAh g−1 at C/5 rate). 相似文献
992.
Johanna H. Kasser Christian G. Hartinger Alexey A. Nazarov Vladimir B. Arion Bernhard K. Keppler 《Journal of organometallic chemistry》2010,695(6):875-2512
Ru(II)-η6-p-cymene compounds bearing pyrone-derived ligands, which were obtained by Mannich reaction with piperidine and related analogues, have been synthesized. The compounds were characterized by NMR spectroscopy, mass spectrometry, thermogravimetric analysis and in the case of 2-(2,6-dimethyl-morpholin-4-ylmethyl)-3-hydroxy-6-hydroxymethyl-pyran-4-one by X-ray diffraction analysis. The chlorido complexes are prone to aquation in aqueous solution which results in the formation of dimers. Dimer formation can be inhibited by in situ replacement of the chlorido ligand by imidazole yielding compounds which are significantly more stable in water, as demonstrated by 1H NMR spectroscopy. 相似文献
993.
994.
995.
We develop here a new class of stochastic models of gene evolution based on residue Insertion-Deletion Independent from Substitution (IDIS). Indeed, in contrast to all existing evolution models, insertions and deletions are modeled here by a concept in population dynamics. Therefore, they are not only independent from each other, but also independent from the substitution process. After a separate stochastic analysis of the substitution and the insertion-deletion processes, we obtain a matrix differential equation combining these two processes defining the IDIS model. By deriving a general solution, we give an analytical expression of the residue occurrence probability at evolution time t as a function of a substitution rate matrix, an insertion rate vector, a deletion rate and an initial residue probability vector. Various mathematical properties of the IDIS model in relation with time t are derived: time scale, time step, time inversion and sequence length. Particular expressions of the nucleotide occurrence probability at time t are given for classical substitution rate matrices in various biological contexts: equal insertion rate, insertion-deletion only and substitution only. All these expressions can be directly used for biological evolutionary applications. The IDIS model shows a strongly different stochastic behavior from the classical substitution only model when compared on a gene dataset. Indeed, by considering three processes of residue insertion, deletion and substitution independently from each other, it allows a more realistic representation of gene evolution and opens new directions and applications in this research field. 相似文献
996.
Calixarene‐bonded stationary phases received growing interest in HPLC as stationary phases with special retention characteristics and selectivity. The commercially available unsubstituted and p‐tert‐butyl‐substituted Caltrex® columns have been intensively studied and characterized in our workgroup. They can be used as reversed phases, yet they support additional interactions. Especially, their steric, polar and ionic properties differ from conventional alkyl‐bonded phases. However, also the hydrophobic interaction shows differences since adsorption and partition interactions on or in a bonded layer of calixarenes are not similar to those of alkyl‐bonded layers. The relative strength of the hydrophobic properties of the stationary phases has been found depending on the methanol concentration of the mobile phase. Generally, the dependencies of their interaction strengths on mobile‐phase conditions, e.g. the change of the intensity of the hydrogen‐bonding abilities with decreasing methanol content, are not similar from phase to phase either. This probably gives calixarene‐bonded stationary phases enhanced suitability for analyses at extreme compositions of the mobile phase. An overview about the synthesis, retention and selectivity properties of Caltrex® columns is given here. 相似文献
997.
This review provides an overview of the most significant strategies developed in recent years for the preparation of donor-functionalized phosphinines and new developments in this field are highlighted. Selected synthetic procedures for the introduction of additional sulfur-, oxygen-, phosphorus-, and nitrogen-donor groups into the heterocyclic framework are presented. Examples of their coordination chemistry and potential applications in homogeneous catalysis and phosphorus containing molecular materials will be given. 相似文献
998.
Anna K. Renfrew Alexander E. Egger Rosario Scopelliti Christian G. Hartinger Paul J. Dyson 《Comptes Rendus Chimie》2010,13(8-9):1144-1150
Metal complexes bearing phosphine ligands are attracting increasing attention for their applications in medicinal chemistry. In particular, organometallic ruthenium-phosphine complexes have been found to exhibit promising antitumour activity. The synthesis, anticancer activity and reactivity of a novel bis-phosphine complex, [Ru(η6-cymene)(PPh2(o-C6H4O)-κ2-P,O)(pta)]Cl (pta = 1,3,5-triaza-7-phosphatricyclo[3.3.1.1.]decane), is presented. The complex appears to exhibit its anticancer effect via a different mechanism to other ruthenium-arene pta complexes with labile co-ligands. 相似文献
999.
Daroui-Mokaddem H Kabouche A Bouacha M Soumati B El-Azzouny A Bruneau C Kabouche Z 《Natural product communications》2010,5(10):1669-1672
The essential oils of fresh leaves of Eucalyptus globulus L. (Myrtaceae), and leaves and stems of Smyrnium olusatrum L. (Apiaceae), obtained by hydrodistillation in a Clevenger-type apparatus, were analyzed by GC/MS. Twenty compounds were characterized, representing 98.3% of the essential oil of E. globulus, with 1,8-cineole (48.6%), globulol (10.9%), trans-pinocarveol (10.7%), and alpha-terpineol (6.6%) as main components, while thirty-three compounds were characterized, representing 94.3% of the essential oil of S. olusatrum, with sabinene (27.1%), curzerene (13.7%), methyl-1-benzyl-2-oxocyclooctane carboxylate (12.3%), alpha-pinene (7.2%), cryptone (7.1%) and beta-pinene (5.7%) as the major components. The essential oils of E. globulus and S. olusatrum were tested against a wide range of fungal and bacterial strains. Both oils showed significant antimicrobial activity. 相似文献
1000.
Krzysztof Ejsmont Joel Boeglin Claude Didierjean Gilles Guichard Christian Jelsch 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(6):o292-o294
The crystal structure of the title compound, C16H23N3O4·CH3CN, was refined using a multipolar atom model transferred from an experimental electron‐density database. The refinement showed some improvement in crystallographic statistical indices compared with the independent atom model. The triazepane ring adopts a twist‐boat conformation. In the crystal structure, the molecule forms intermolecular contacts with 14 different neighbours. There are two N—H...O and one C—H...O intermolecular hydrogen bond. 相似文献