Search results for "Supramolecular"
showing 10 items of 830 documents
Improving the mesomorphic behaviour of supramolecular liquid crystals by resonance-assisted hydrogen bonding
2019
A systematic structure-property relationship study on hydrogen-bonded liquid crystals was performed, revealing the impact of resonance-assisted hydrogen bonds (RAHBs) on the self-assembling behavior of the supramolecular architecture. The creation of a six-membered intramolecular hydrogen-bonded ring acts as a counterpart to the self-organization between hydrogen bond donators and acceptors and determines thus the suprastructure. Variation of the hydrogen-bonding pattern allowed us to significantly improve the temperature range of the reported liquid crystalline assemblies.
A novel supramolecular assembly in an iron(III) compound exhibiting magnetic ordering at 70 K
2004
Ethyl-substituted ammonium cation allows the preparation of an unprecedented oxo- and oxalato-bridged supramolecular three-dimensional network. The compound exhibits magnetic ordering with Tc = 70 K due to a weak spin canting. Julve Olcina, Miguel, Miguel.Julve@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es
Magneto-structural correlations in self-assembled spin-transition nano-architectures of the [][2×2]-grid-type
2004
Abstract The magnetism of a series of tetranuclear complexes of the [ Fe II 4 L 4 ]( BF 4 ) 8 [2×2] -grid-type was investigated, revealing the occurrence of spin-transition (ST) behavior within this class of compounds. The phenomenon depends directly on the nature of the substituent R1 of the ligand L . All FeII ions in compounds with R1 substituents favoring strong ligand fields ( R 1 = H ; OH ) remain completely in the diamagnetic low-spin state. Only the complex bearing R1=Ph exhibits thermally induced ST behavior.
Long-Living Light-Emitting Electrochemical Cells - Control through Supramolecular Interactions
2008
Light-emitting electrochemical cells with lifetimes surpassing 3000 hours at an average luminance of 200 cd m(-2) are obtained with an ionic iridium(III) complex conveniently designed to form a supramolecularly caged structure.
Two-Dimensional Aggregation of Organogelators Induced by Biaxial Hydrogen-Bonding Gives Supramolecular Nanosheets
2007
Photochemical and Chemical Two-Channel Control of Functional Nanogated Hybrid Architectures
2007
The supramolecular self-organization of an amphotropic cholesterol derivative Micelles, liposomes and liquid-crystalline phases
1993
Abstract The cholesterol derivative tetraethoxycholesteryl semisuccinate is both a mesogen and an amphiphile. This combination of both molecular prerequisites permits two types of supramolecular self-organization: the formation of a thermotropic liquid-crystalline phase and of various forms of aggregates in contact with water or other solvents. Depending on the pH of the aqueous medium the compound self organizes in micelles or liposomes. At high concentrations lyotropic liquid-crystalline phases are obtained. The formation of liposomes and lyotropic phases is not restricted to water as a solvent but can also be induced in pure organic media such as water-free diethyleneglycol. Due to the b…
Polyester and Ester Functionalized Dendrimers
2000
Demand for smart and functional materials has raised the importance of the research of dendritic (Greek = tree-like) molecules in organic and polymer chemistry due to their novel physical and mechanical properties. The properties of linear polymers as well as small discrete molecules are combined in this new architectural class of macromolecules, that can be divided into two families: dendrimers and hyperbranched macromolecules, that differ in their branching sequences. Dendrimers contain symmetrically arranged branches emanating from a core molecule together with a well-defined number of end groups corresponding to each generation. This results in an almost monodisperse three-dimensional g…
Deconvolution of the Effects of Binary Associations and Collective Assemblies on the Rheological Properties of Entangled Side-Chain Supramolecular Po…
2019
The properties and function of supramolecular polymer networks are determined not only by pairwise interchain transient associations but also by chain entanglement and nanoscopic phase separation of the associative groups. To unravel the impact and interplay of these different factors, we devise a set of model supramolecular polymer networks in which the number of entanglements and the density of associative groups are systematically varied. Rheological data show that by increasing the density of associative groups, the plateau modulus grows to a steady level and extends over a distinct frequency range. This is credited to the presence of binary associations with unique partner exchange tim…