Highly defined, colloid-like ionic clusters in solution.
Ontology highlight
ABSTRACT:
SUBMITTER: Kurzbach D
PROVIDER: S-EPMC3922591 | biostudies-literature | 2012 Oct
REPOSITORIES: biostudies-literature
Publications
Highly defined, colloid-like ionic clusters in solution.
Kurzbach Dennis D Kattnig Daniel R DR Pfaffenberger Nane N Schärtl Wolfgang W Hinderberger Dariush D
ChemistryOpen 20120905 5
Similar Datasets
Project description:Supertetrahedral clusters have been reported in two generally different types so far: one type possessing an organic ligand shell, no or low charges, and high solubility, while the other cluster type is ligand-free with usually high charges and low or no solubility in common solvents. The latter is a tremendous disadvantage regarding further use of the clusters in solution. However, as organic substituents usually broaden the HOMO-LUMO gaps, which cannot be overcompensated by the (limited) cluster sizes, a full organic shielding comes along with drawbacks regarding opto-electronic properties. We therefore sought to find a way of generating soluble clusters with a minimum number of organic substituents. Here, we present the synthesis and full characterization of two salts of [Sn10 O4 S16 (SBu)4 ]4- that are high soluble in CH2 Cl2 or CH3 CN, which includes first NMR and mass spectra obtained from solutions of such salts with mostly inorganic supertetrahedral clusters. The optical absorption properties of this new class of compounds indicates nearly unaffected band gaps. The synthetic approach and the spectroscopic findings were rationalized and explained by means of high-level quantum chemical studies.
| S-EPMC8362043 | biostudies-literature
Project description:The micellar aggregation of singly charged sequence-defined ionic peptoid block copolymers can be finely tuned by adjusting the position of the ionizable monomer along the chain and varying the solution pH. The pH-induced structural reorganization of these micelles was found to depend on the position of the ionizable monomer along the chain, influencing the balance of the hydrophobic interactions, excluded volume effect, and electrostatic forces (i.e., charge repulsion, solvation of the ionic monomers, counterion association) that govern the micellar structure. As the solution pH increases, positioning the ionizable monomer closer to the junction of the hydrophobic and hydrophilic blocks causes a larger reduction in the micellar size and aggregation number across two distinct regimes. In contrast, placing the ionizable monomer at the terminus of the hydrophilic block results in a smaller reduction in the micellar size and aggregation number over three regimes. This study provides new insights into leveraging the strategic positioning of ionizable monomers to design stimuli-responsive nanoassemblies capable of programmable structural reorganization.
| S-EPMC11866915 | biostudies-literature
Project description:Exploration of metal clusters (MCs) adaptive to both aqueous and oil phases without disturbing their size is promising for a broad scope of applications. The state-of-the-art approach via ligand-binding may perturb MCs' size due to varied metal-ligand binding strength when shuttling between solvents of different polarity. Herein, we applied physical confinement of a series of small noble MCs (<1 nm) inside ionic organic cages (I-Cages), which by means of anion exchange enables reversible transfer of MCs between aqueous and hydrophobic solutions without varying their ultrasmall size. Moreover, the MCs@I-Cage hybrid serves as a recyclable, reaction-switchable catalyst featuring high activity in liquid-phase NH3BH3 (AB) hydrolysis reaction with a turnover frequency (TOF) of 115 min-1.
| S-EPMC6354838 | biostudies-literature
Project description:A series of highly-fluorinated triaminocyclopropenium salts, with up to six fluorous groups, were prepared and their properties as ionic liquids investigated. Reaction of pentachlorocyclopropane or tetrachlorocyclopropene with bis(2,2,2-trifluoroethyl)amine, HN(CH2 CF3 )2 , occurs in the presence of a trialkylamine, NR3 , to give cations with two fluorinated amino groups, [C3 (N(CH2 CF3 )2 )2 (NR2 )]+ (R=Et, Pr, Bu, Hex), with traces of [C3 (N(CH2 CF3 )2 )3 ]+ . Use of appropriate reagent ratios and reaction times and subsequent addition of a dialkylamine, HNR'R", gives cations with one fluorinated amino group, [C3 (N(CH2 CF3 )2 )(NR2 )(NR'R")]+ ((NR2 )(NR'R")=(NBu2 )2 , (NEt2 )(NPr2 ), (NBu2 )(NBuMe)). These cations were isolated as chloride salts and some of these were converted to bistriflamide, dicyanamide and triflate salts to provide ionic liquids. These salts were characterised by thermal (DSC and TGA) measurements and miscibility/solubility properties (determined in a range of solvents). Ionic liquids (ILs) were also characterised by density, viscosity and conductivity measurements where possible. X-ray diffraction studies of chloride salts showed the formation of fluorous regions and more hydrophilic ionic regions in the solid state.
| S-EPMC9314049 | biostudies-literature
Project description:The agglomeration of silica nanoparticles in aqueous solution is investigated from molecular simulations. Mimicking destabilization of colloidal solutions by full removal of protective moieties or surface charge, association of SiO2/Si(OH)4 core/shell particles leads to rapid proton transfer reactions that account for local silanole → silica ripening reactions. Yet, such virtually barrier-less binding is only observed within a limited contact zone. Agglomeration hence leads to the formation of oligomers of nanoparticles, whilst full merging into a compact precipitate is hampered by the need for extended structural reorganisation. Implementing sufficiently fast supply from colloidal solution, our simulations show the development of silica networks comprised of covalently bound, yet not fully merged nanoparticles. Within the oligomerized nanoparticle network, coordination numbers range from 2 to 5 -which is far below closest packing. Our simulations hence rationalize the formation of covalently bound network structures hosting extended pores. The resulting interfaces to the solvent show water immobilization only for the immediate contact layers, whilst the inner pores exhibit solvent mobility akin to bulk water.
| S-EPMC6405164 | biostudies-literature
Project description:Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide in water with calcium ions. Through biomineralization, organisms can harness and control this process to form various functional materials that can act as anything from shells through to lenses. The early stages of calcium carbonate formation have recently attracted attention as stable prenucleation clusters have been observed, contrary to classical models. Here we show, using computer simulations combined with the analysis of experimental data, that these mineral clusters are made of an ionic polymer, composed of alternating calcium and carbonate ions, with a dynamic topology consisting of chains, branches and rings. The existence of a disordered, flexible and strongly hydrated precursor provides a basis for explaining the formation of other liquid-like amorphous states of calcium carbonate, in addition to the non-classical behaviour during growth of amorphous calcium carbonate.
| S-EPMC3247826 | biostudies-literature
Project description:Supertetrahedral chalcogenido (semi)metalate clusters have been in the focus of inorganic and materials chemistry for many years owing to a variety of outstanding physical and chemical properties. However, a critical drawback in the canon of studying corresponding compounds has been the lack of control in assembling the supertetrahedral units, which have been known as either highly charged monomeric cluster anions or lower charged, yet extended anionic substructures of linked clusters. The latter is the reason for the predominance of applications of such materials in heterogeneous environment, or their solubilization by organic shielding, which in turn was unfavorable regarding the optical properties. Recently, we reported a partial alkylation of such clusters, which allowed for a significantly enhanced solubility at a marginal impact on the optical gap. Herein we showcase the formation of finite cluster oligomers of supertetrahedral architectures by ionothermal syntheses. We were successful in generating the unprecedented dimers and tetramers of the [Ge4Se10]4- anion in salts with imidazolium-based ionic liquid counterions. The oligomers exhibit lower average negative charges and thus reduced electrostatic interactions between anionic clusters and cationic counterions. As a consequence, the salts readily dissolve in common solvents like DMF. Besides, the tetrameric [Ge16Se36]8- anion represents the largest discrete chalcogenide cluster of a group 14 element. We prove that undestroyed cluster oligomers can be transferred into solution by means of electrospray ionization (ESI) mass spectrometry and provide a full set of characteristics of the compounds including crystal structures and optical properties.
| S-EPMC8790736 | biostudies-literature
Project description:Atomic charges were investigated as functions of detectable atomic and molecular constants at equilibrium structures. It was found based upon the variation idea that atomic charges in highly ionic molecules can be expressed as a function of molecular dipole moments, polarizabilities of free cations, and polarizabilities of free neutral atoms of the corresponding anions. The function can be given in the form of classical Rittner's relationship (J. Chem. Phys. 1951, 19, 1030). For the ground states of alkali halide molecules, the predicted atomic charges are close to an elementary charge e and the predicted dipole moments are in good agreement with the observed values; for spin-restricted high-ionic systems such as the lowest 9Σ electronic states of BN, AlN, GaN, BP, AlP, GaP, BAs, AlAs, and GaAs molecules, the predicted atomic charges are also near 1e and in good agreement with the results of natural population analysis at MRCI/cc-pvqz and HF/6-311+G(3df) levels. Polarizabilities for the lowest quintet states of B-, Al-, Ga-, N+, P+, and As+ ions were also obtained based upon high-level ab initio computations. Atomic charges from other related methods are also investigated for comparison. The results demonstrate that high-quality atomic charges can be obtained with detectable variables, such as molecular dipole moment, vibrational frequency, as well as polarizabilities of the related free atoms and ions.
| S-EPMC6643469 | biostudies-literature
Project description:Traditional elastomers are mostly dielectrics; existing conductive elastomers are conductive composites with electric conductors. Herein, we introduce a series of ionic conducting elastomers (ICE) by salt in polymer strategy. The ICEs possess good stretchability, transparency and ionic conductivity. Moreover, the ICEs exhibit very high stability in air, under high temperature and voltage, with excellent adhesion properties and no corrosive effects to metal electrodes. Touch sensors are fabricated using these ICEs-impedance spectra and impedance complex plane are tested and analyzed to clarify different stimulus of the touch sensors. These ICEs provide possibilities for flexible electronics and soft machines.
| S-EPMC6035269 | biostudies-literature
Project description:To understand the existence of complex meso-sized solute-rich clusters, which challenge the understanding of phases and phase equilibria, the formation and stabilization mechanisms of clusters in solution during nucleation of crystals and the associated physico-chemical rules are studied in detail. An essential part of the mechanism is the formation of long-lived oligomers between solute molecules. By means of density functional theory simulation and nuclear magnetic resonance experiments, this work showed that the oligomers in solution tend to be π-π stacking dimers. Clusters are formed under the combined effect of diffusion and monomer-dimer reaction. The physically meaningful quantities such as the monomer-dimer reaction rate constants and the diffusion coefficients of both species were obtained by reaction-diffusion kinetics and diffusion-ordered spectroscopy results. The evolution of cluster radius as a function of time, and the qualitative spatial distributions of monomer and dimer densities under steady-state were plotted to better understand the formation process and the nature of the clusters.
| S-EPMC8895010 | biostudies-literature