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3D Micro/Nanopatterning of a Vinylferrocene Copolymer
(2020-05-23)
In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the filling of the imprint stamp and its subsequent detachment may impose some practical challenges. Here we explored thermal and reverse NIL patterning of polyvinylferrocene and vinylferrocene-methyl methacrylate copolymers to prepare complex non-spherical objects and patterns. While neat polyvinylferrocene was found to be unsuitable for NIL, freshly-prepared ...
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Homodinuclear Rhˡ and Irˡ Complexes Derived from Imidazolium-Benzimidazolates
(2020-11-19)
The reactions of [M(μ-Cl)(COD)]2 (M=Rh, Ir) with the conjugated mesomeric betaines 2-(3-methyl-1-imidazolium)-benzimidazolate (1aH), 2-(3-isopropyl-1-imidazolium)-benzimidazolate (1bH) and 2-(3-tert-butyl-1-imidazolium)-benzimidazolate (1cH) in equilibrium with their carbenic tautomers 1’aH, 1’bH and 1’cH were investigated. In the case of 1aH and 1bH, the homodinuclear complexes [MCl(COD){M(μ-1’a)(COD)}] and [MCl(COD){M(μ-1’b)(COD)}] were obtained, whose anionic NHC ligand 1’a− or 1’b− bridges the metal centres in a ...
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Synthesis, Structure and Cu-Phenylacetylide Coordination of an Unsymmetrically Substituted Bulky dppf-Analog
(2021-12-03)
The donor properties of a set of bulky ferrocene based bisphosphanes (Fe(C₅H₄PMes₂)₂ and (C₅H₄PMes₂)Fe(C₅H₄PᵗBu₂ with Mes= mesityl and ᵗBu=tert-butyl) were probed by exploring the NMR parameters of the corresponding selenophosphoranes amended by cyclovoltammetry. The ligand properties were explored in the complexation of copper phenylacetylide which is relevant as intermediate in the Cu(I) catalyzed CO₂ addition to phenylacetylene. Owing to the poor solubility of the resulting complexes their characterization was ...
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Tailoring Phospholes for Imprint of Fluorescent 3D Structures
(2019-11-06)
PMMA based polymer blends have been infused with luminescent phospholes and have been structured via nanoimprint. While symmetrically substituted phospholes are prone to crystallization and phase separation, structural modification of the phosphole backbone in the α‐ and β‐positions has been explored, which prevents these issues; a structural explanation for this is suggested. Best phase integrity has been obtained for β‐silyl‐substituted phospholes, which were implemented in thin films and beads. The emission ...
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Site-specific interrogation of an ionic chiral fragment during photolysis using an X-ray free-electron laser
(2021-08-12)
Short-wavelength free-electron lasers with their ultrashort pulses at high intensities have originated new approaches for tracking molecular dynamics from the vista of specific sites. X-ray pump X-ray probe schemes even allow to address individual atomic constituents with a ‘trigger’-event that preludes the subsequent molecular dynamics while being able to selectively probe the evolving structure with a time-delayed second X-ray pulse. Here, we use a linearly polarized X-ray photon to trigger the photolysis of a ...
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Mineralization of Phosphorylated Fish Skin Collagen/Mangosteen Scaffolds as Potential Materials for Bone Tissue Regeneration
(2021-05-13)
In this study, a potential hard tissue substitute was mimicked using collagen/mangosteen porous scaffolds. Collagen was extracted from Tilapia fish skin and mangosteen from the waste peel of the respective fruit. Sodium trimetaphosphate was used for the phosphorylation of these scaffolds to improve the nucleation sites for the mineralization process. Phosphate groups were incorporated in the collagen structure as confirmed by their attenuated total reflection Fourier transform infrared (ATR-FTIR) bands. The phosphorylation ...
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Wine quality under integrated, organic and biodynamic management using image-forming methods and sensory analysis
(2021-12-24)
Background and aims
The image-forming methods copper chloride crystallization, capillary dynamolysis and circular chromatography are presented as an instrument for assessing wine quality. Wine quality of samples from a long-term field trial comparing integrated, organic and biodynamic management were investigated by using image-forming methods and sensory analysis.
Methods and results
Concerning the image-forming methods copper chloride crystallization, capillary dynamolysis and circular chromatography, the images ...
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Photoinduced supramolecular chirality and spontaneous surface patterning in high-performance azo materials
(2019-06-18)
In this work, two photo-structuring processes, photo induced spontaneous surface structuring (PSSP) and photo induced supramolecular chirality (PSC) are applied to high-performance azo polymers. We demonstrate higher induced optical rotation than described previously in other reports and show that self-organized surface morphologies are not detrimental for the formation of PSC.
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Amplified Spontaneous Emission in Paper
(2019-02-12)
Industrially produced copy paper is presented as a novel optical material for narrow-band stimulated emission. Fluorescent brightening agents (FBA) such as Calcofluor White provide enough gain to exceed the threshold for amplified spontaneous emission. By applying an additional dye such as Coumarin 307, or simply a highlighter pen, the emission line can be shifted from blue (~440 nm), towards turquoise (>480 nm), up to orange (590 nm) which can be useful for spectroscopic applications. These properties are demonstrated ...
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Chalcogen‐Transfer Rearrangement: Exploring Inter‐ versus Intramolecular P−P Bond Activation
(2020-07-17)
tert‐Butyl‐substituted diphospha[2]ferrocenophane has been used as a stereochemically confined diphosphane to explore the addition of O, S, Se and Te. Although the diphosphanylchalcogane has been obtained for tellurium, all other chalcogens give diphosphane monochalcogenides. The latter transform via chalcogen‐transfer rearrangement to the corresponding diphosphanylchalcoganes upon heating. The kinetics of this rearrangement has been followed with NMR spectroscopy supported by DFT calculations. Intermediates during ...