Probing Molecular Structures of Poly(dimethylsiloxane) at Buried Interfaces in Situ

2013 ◽  
Vol 117 (8) ◽  
pp. 3903-3914 ◽  
Author(s):  
Chi Zhang ◽  
Zhan Chen
Keyword(s):  
Molecular Structures ◽  
Buried Interfaces

scholarly journals Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes

2014 ◽  
Vol 10 ◽  
pp. 714-721 ◽  
Author(s):  
Yuta Takano ◽  
Yuki Nagashima ◽  
M Ángeles Herranz ◽  
Nazario Martín ◽  
Takeshi Akasaka
Keyword(s):  
Thermal Stability ◽  
Material Science ◽  
Molecular Structures ◽  
Spectroscopic Methods ◽  
Dynamic Nmr ◽  
The Novel ◽  
Endohedral Metallofullerenes ◽  
Derivatives Of ◽  
Paramagnetic Properties

The [4 + 2] cycloaddition of o-quinodimethanes, generated in situ from the sultine 4,5-benzo-3,6-dihydro-1,2-oxathiin 2-oxide and its derivative, to La metal-encapsulated fullerenes, La2@C80 or La@C82, afforded the novel derivatives of endohedral metallofullerenes (3a,b, 4a,b and 5b). Molecular structures of the resulting compounds were elucidated using spectroscopic methods such as MALDI–TOF mass, optical absorption, and NMR spectroscopy. The [4 + 2] adducts of La2@C80 (3a,b, and 4a,b) and La@C82 (5b), respectively, retain diamagnetic and paramagnetic properties, as confirmed by EPR spectroscopy. Dynamic NMR measurements of 4a at various temperatures demonstrated the boat-to-boat inversions of the addend. In addition, 5b revealed remarkable thermal stability in comparison with the reported [4 + 2] cycloadduct of pentamethylcyclopentadiene and La@C82 (6). These findings demonstrate the utility of sultines to afford thermodynamically stable endohedral metallofullerene derivatives for the use in material science.

scholarly journals A method for pet mechanical properties enhancement

2019 ◽  
Vol 10 (8) ◽  
pp. 1725
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Virgil Petrescu ◽  
Antonio Apicella ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Molecular Structures ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Shear Transfer ◽  
Crystalline Polymers ◽  
Reactive Compatibilizer

A method for PET mechanical properties enhancement by reactive blending with HBA/HNA Liquid Crystalline Polymers for in situ highly fibrillar composites preparation is presented. LCP/PET blends were reactively extruded in presence of Pyromellitic Di-Anhydride (PMDA) and then characterized by Differential Scanning Calorimetry, Thermally Stimulated Currents and tensile mechanical properties. Moderate amounts of LCP in the PET (0.5 and 5%) and small amounts of thermo-active and reactive compatibilizer in the blend (0.3%) were found to significantly improve LCP melt dispersion, melts shear transfer and LCP fibril formation and adhesion. An unexpected improvement was probably due to the presence of two distinct phases’ supra-molecular structures involving PET-LCP and PMDA.

X-RAY DIFFRACTION FOR SURFACES AND BURIED INTERFACES

2000 ◽  
Vol 07 (04) ◽  
pp. 437-446 ◽  
Author(s):  
G. RENAUD
Keyword(s):  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Buried Interfaces ◽  
Surfaces And Interfaces ◽  
Coherent Interfaces

The application of X-rays to the structural characterization of surfaces and interfaces, in situ and in UHV, is discussed on selected examples. Grazing incidence X-ray diffraction is not only a very powerful technique for quantitatively investigating the atomic structure of surfaces and interfaces, but is also very useful for providing information on the interfacial registry for coherent interfaces or on the strain deformation, island and grain sizes for incoherent epilayers.

Photochemische Reaktionen von Übergangsmetall-Organyl-Komplexen mit Olefinen, XVI [1]: Photochemisch induzierte Cycloadditionen von Diphenylacetylen an Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)mangan / Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, XVI [1]: Photochemically Induced Cycloadditions of Diphenylacetylene to Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)manganese

1996 ◽  
Vol 51 (10) ◽  
pp. 1473-1485 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Ernst-Christian Koch ◽  
Walter Frank ◽  
Guido J. Reiß
Keyword(s):  
Mass Spectra ◽  
Photochemical Reactions ◽  
Molecular Structures ◽  
Manganese Complexes ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray

Upon UV irradiation in THF at 208 K tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)- manganese (1) yields solvent stabilized, very reactive dicarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)(tetrahydrofuran)manganese (2), which reacts in situ with one or two molecules of diphenylacetylene (3) and yields four manganese complexes and 1,3-dimethyl-5,6-diphenyl-bicyclo[3.2.1]oct-2-ene-7-one (5), which were separated by HPL chromatography. In addition to tricarbonyl η5-4,6 -dimethyl-1,2-diphenyl-cyclohepta-2,4-dien-1-yl)manganese (4) formed by [5+2]cycloaddition and successive 1,4-H shift, tricarbonyl{ 1′,2′,5′-η-5-methyl-2,3 -diphenyl-5- (2′-methyl-4′,5′-diphenyl-penta-1′,4′-dien-1′,5′-diyl)cyclopent-2-en-1 -one-κ-O}manganese (6) is isolated with a ligand, formed from 2,4-dimethyl-2,4-pentadien-1-yl, two units of 3 and one carbon monoxide. The ligands of tricarbonyl{ 1-4,2′-η-4,6 -dimethyl-1,2-diphenyl-5-(E-1′,2′- diphenyl-vinylen)cyclohepta-1,3-diene}manganese (7), and tricarbonyl{η5-4,6 -dimethyl-1,2-diphenyl-7-(E-1′,2′-diphenyl-vinyl)cyclohepta-2,4-dien-1-yl}m anganese (8) are formed from 2,4-dimethyl-2,4-pentadien-1-yl and of two molecules of 3 each. The crystal and molecular structures of 5 and 6 have been determined by single crystal X-ray diffraction. 5 crystallizes in the triclinic space group P1̅ , a = 992.0(2) pm, b = 996.8(2) pm, c = 1021.0(2) pm, a = 77.67(3)°, β = 61.17(3)°, γ = 88.68(3)°. Complex 6 crystallizes also in the triclinic space group P1̅ ,a = 1023.2(2) pm, b - 1113.8(2) pm, c = 1567.9(3) pm, α = 82.88(3)°, β = 86.93(3)°, 7 = 63.53(3)°. The constitutions of 4, 7 and 8 were elucidated from the IR, NMR and mass spectra. Possible formation mechanisms for the compounds 4-8 are proposed. Complex 7 shows hindered rotations of two phenyl groups with different barriers of energy ΔG≠316 = 68.8 kJ/mol, „ΔH≠ = 67.9 ± 0.7 kJ/mol, ΔS≠ = -2 ± 2 J/mol · K and ΔG≠296 = 60.6 kJ/mol, ΔH≠ = 57.7 ± 1.0 kJ/mol, ΔS≠ = -10 ± 2 J/mol·K due to steric interactions.

Self-assembly of aniline oligomers and their induced polyaniline supra-molecular structures

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Jing Feng ◽  
Xinli Jing ◽  
Yu Li
Keyword(s):  
Recent Work ◽  
Self Assembly ◽  
Chemical Oxidation ◽  
Molecular Structures ◽  
Oxidation Products ◽  
Assembly Process ◽  
Controllable Synthesis ◽  
Aniline Oligomers ◽  
Future Work

AbstractAniline chemical oxidative polymerisation (COP), which produces various polyaniline (PANI) and oligoaniline supra-molecular structures, can be regarded as an in situ self-assembly process. This review provides a brief introduction to recent work on the structural characters and self-assembly behaviours of oligomeric aniline chemical oxidation products; it is focused on the relationships between the oligomeric species and morphology of the final products such as PANI nanoparticles, nanofibres/rods, nanotubes or oligoaniline nanosheets, micro/nanospheres in aniline COP systems. Several mechanisms proposed as explanations for the formation of typical supra-molecular structures are discussed in order to illustrate the roles of aniline oligomers. This article concludes with our perspectives on future work remaining to be done to uncover the formation mechanism of supra-molecular structures constructed by aniline chemical oxidation products and their controllable synthesis.

scholarly journals Probing Protein Aggregation at Buried Interfaces: Distinguishing Adsorbed Protein Monomer, Dimer, and Monomer-Dimer Mixture in Situ

2022 ◽  
Author(s):  
Tieyi Lu ◽  
Wen Guo ◽  
Datar M. Prathamesh ◽  
Yue Xin ◽  
E. Neil G. Marsh ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Protein Adsorption ◽  
Protein Drug ◽  
Protein Drugs ◽  
Biomedical Materials ◽  
Drug Adsorption ◽  
Separation Membranes ◽  
Buried Interfaces ◽  
Adsorbed Protein

Protein adsorption on surfaces greatly impacts many applications such as biomedical materials, anti-biofouling coatings, bio-separation membranes, biosensors, and antibody protein drugs etc. For example, protein drug adsorption on widely used...

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