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931.
Rong‐Ming Ho Tsai‐Ming Chung Jing‐Cherng Tsai Jing‐Chang Kuo Benjamin S. Hsiao Igors Sics 《Macromolecular rapid communications》2005,26(2):107-111
Summary: Various crystalline textures have been identified in a crystallizable block copolymer system, polystyrene‐block‐[syndiotactic poly(propylene)] (PS‐sPP), having a glass‐transition temperature of PS (Tg,PS) located in the midst of the sPP crystallization window. A confined morphology for the crystallization of sPP was observed while the crystallization temperature of sPP (Tc,sPP) was less than Tg,PS. A further increase in Tc,sPP could lead to a breakout in nanostructure. This study revealed the Tg effect on crystallization‐induced morphological changes of block copolymers from confinement to breakout.
932.
Li Fang Benjamin L. Davis Haiyan Lu John R. Lombardi 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(14)
In an excitation range of 620–760 nm, resonance Raman spectra of aluminum dimers (Al2) in an argon matrix have been obtained for the first time. Temperature annealing experiments were performed to remove Raman lines attributed site effects caused by the Al2/Ar matrix. We observe a single fundamental at 293.3 (5) cm−1 along with a progression up to 1149 (1) cm−1. Taking successive differences of band centers we obtain spectroscopic constants for the ground state fundamental, ωe=297.5 (5) cm−1, the anharmonicity, ωexe=1.68 (8) cm−1. Our results are in close agreement with previous experimental results for Al2 which designate the ground state as a 3Πu state, and may be considered as confirmation of this assignment. 相似文献
933.
Daniel J. Williams Daniel Gulla Kimberly A. Arrowood Lindsey M. Bloodworth Angela L. Carmack Taylor J. Evers Mark S. Wilson Javier J. Concepcion Carol A. S. Brevett Benjamin E. Huck Donald VanDerveer 《Journal of chemical crystallography》2009,39(8):581-584
Abstract A new compound, [Cd(mipit)4][PF6]2 has been synthesized and characterized via standard solid and solution state methods including single crystal X-ray crystallography
(mipit = 1-methyl-3-(2-propyl)-2(3H)-imidazolethione). The title compound crystallizes in tetragonal space group I4
1
/a with a = 12.478(2) ?, b = 12.478(2) ?, c = 28.806(6) ?, and Z = 4. The complex is a high melting, colorless solid that has a distorted tetrahedral CdS4 coordination geometry. Thermogravimetric analysis results for the title compound as well as for another potential CdS synthon
and two potential CdSe synthons are reported.
Graphical Abstract The synthesis and characterization of the title compound, a new ionic homoleptic cadmium complex, tetrakis[1-methyl-3-(2-propyl)-2(3H)-imidazolethione]cadmium(II)
hexafluorophosphate is reported. The results of a single crystal X-ray diffraction analysis reveal a distorted tetrahedral
CdS4 coordination sphere about the cadmium.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
934.
935.
Structural Chemistry - The conformation-selective IR spectroscopy of the alanine dipeptide analogue Ac-Ala-NH2, a molecule deprived of a UV chromophore, has been obtained by laser double-resonance... 相似文献
936.
Maria N. Tamaño‐Machiavello Benjamin Bracke Carlos M. Costa Senentxu Lanceros‐Mendez Roser Sabater i Serra José Luis Gómez Ribelles 《Journal of Polymer Science.Polymer Physics》2016,54(6):672-679
Polymer blend membranes have been obtained consisting of a hydrophilic and a hydrophobic polymers distributed in co‐continuous phases. In order to obtain stable membranes in aqueous environments, the hydrophilic phase is formed by a poly(hydrohyethyl acrylate), PHEA, network while the hydrophobic phase is formed by poly(vinylidene fluoride‐co‐trifluoroethylene) P(VDF‐TrFE). To obtain the composites, in a first stage, P(VDF‐TrFE) is blended with poly(ethylene oxyde) (PEO), the latter used as sacrificial porogen. P(VDF‐TrFE)/PEO blend membranes were prepared by solvent casting at 70°C followed by cooling to room temperature. Then PEO is removed from the membrane by immersion in water obtaining a P(VDF‐TrFE) porous membrane. After removing of the PEO polymer, a P(VDF‐TrFE) membrane results in which pores are collapsed. Nevertheless the pores reopen when a mixture of hydroxethyl acrylate (HEA) monomer, ethyleneglycol dimethacrylate (as crosslinker) and ethanol (as diluent) is absorbed in the membrane and subsequent polymerization yields hybrid hydrophilic/hydrophobic membranes with controlled porosity. The membranes are thus suitable for lithium‐ion battery separator membranes and/or biostable supports for cell culture in biomedical applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 672–679 相似文献
937.
Randall D. Maples Amy N. Cain Dr. Benjamin P. Burke Dr. Jon D. Silversides Dr. Ryan E. Mewis Thomas D'huys Prof. Dominique Schols Prof. Douglas P. Linder Prof. Stephen J. Archibald Prof. Timothy J. Hubin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12916-12930
The CXCR4 chemokine receptor is implicated in a number of diseases including HIV infection and cancer development and metastasis. Previous studies have demonstrated that configurationally restricted bis‐tetraazamacrocyclic metal complexes are high‐affinity CXCR4 antagonists. Here, we present the synthesis of Cu2+ and Zn2+ acetate complexes of six cross‐bridged tetraazamacrocycles to mimic their coordination interaction with the aspartate side chains known to bind them to CXCR4. X‐ray crystal structures for three new Cu2+ acetate complexes and two new Zn2+ acetate complexes demonstrate metal‐ion‐dependent differences in the mode of binding the acetate ligand concomitantly with the requisite cis‐V‐configured cross‐bridged tetraazamacrocyle. Concurrent density functional theory molecular modelling studies produced an energetic rationale for the unexpected [Zn(OAc)(H2O)]+ coordination motif present in all of the Zn2+ cross‐bridged tetraazamacrocycle crystal structures, which differs from the chelating acetate [Zn(OAc)]+ structures of known unbridged and side‐bridged tetraazamacrocyclic Zn2+‐containing CXCR4 antagonists. 相似文献
938.
David Bialas Christoph Brüning Dr. Felix Schlosser Dr. Benjamin Fimmel Johannes Thein Prof. Dr. Volker Engel Prof. Dr. Frank Würthner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(42):15011-15018
The optical properties of a series of three cyclophanes comprising either identical or different perylene bisimide (PBI) chromophores were studied by UV/Vis absorption spectroscopy and their distinctive spectral features were analyzed. All the investigated cyclophanes show significantly different absorption features with respect to the corresponding constituent PBI monomers indicating strong coupling interactions between the PBI units within the cyclophanes. DFT calculations suggest a π‐stacked arrangement of the PBI units at close van der Waals distance in the cyclophanes with rotational displacement. Simulations of the absorption spectra based on time‐dependent quantum mechanics properly reproduced the experimental spectra, revealing exciton‐vibrational coupling between the chromophores both in homo‐ and heterodimer stacks. The PBI cyclophane comprising two different PBI chromophores represents the first example of a PBI heterodimer stack for which the exciton coupling has been investigated. The quantum dynamics analysis reveals that exciton coupling in heteroaggregates is indeed of similar strength as for homoaggregates. 相似文献
939.
Alexandra Gaubert Yohann Clement Anne Bonhomme Benjamin Burger Delphine Jouan-Rimbaud Bouveresse Douglas Rutledge Hervé Casabianca Pierre Lanteri Claire Bordes 《Analytica chimica acta》2016
This paper presents the analysis of surfactants in complex mixtures using Raman spectroscopy combined with signal extraction (SE) methods. Surfactants are the most important component in laundry detergents. Both their identification and quantification are required for quality control and regulation purposes. Several synthetic mixtures of four surfactants contained in an Ecolabel laundry detergent were prepared and analyzed by Raman spectroscopy. SE methods, Independent Component Analysis and Multivariate Curve Resolution, were then applied to spectral data for surfactant identification and quantification. The influence of several pre-processing treatments (normalization, baseline correction, scatter correction and smoothing) on SE performances were evaluated by experimental design. By using optimal pre-processing strategy, SE methods allowed satisfactorily both identifying and quantifying the four surfactants. When applied to the pre-processed Raman spectrum of the Ecolabel laundry detergent sample, SE models remained robust enough to predict the surfactant concentrations with sufficient precision for deformulation purpose. Comparatively, a supervised modeling technique (PLS regression) was very efficient to quantify the four surfactants in synthetic mixtures but appeared less effective than SE methods when applied to the Raman spectrum of the detergent sample. PLS seemed too sensitive to the other components contained in the laundry detergent while SE methods were more robust. The results obtained demonstrated the interest of SE methods in the context of deformulation. 相似文献
940.