Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Integrated molecular chirality, absolute helicity, and intrinsic chiral topology in three-dimensional open-framework materials.

ABSTRACT: While chiral materials are common, few are known that integrate molecular chirality, absolute helicity, and 3-D intrinsically chiral topological nets in one material. Such multihomochiral features may lead to enhanced chiral recognition processes that are important for enantioselective catalysis or separation. Reported here are a series of 3-D open-framework materials with unusual integration of various homochiral and homohelical features, even in the bulk sample.

SUBMITTER: Zhang J

PROVIDER: S-EPMC2782683 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Integrated molecular chirality, absolute helicity, and intrinsic chiral topology in three-dimensional open-framework materials.

Zhang Jian J Chen Shumei S Zingiryan Areg A Bu Xianhui X

Journal of the American Chemical Society 20081201 51

While chiral materials are common, few are known that integrate molecular chirality, absolute helicity, and 3-D intrinsically chiral topological nets in one material. Such multihomochiral features may lead to enhanced chiral recognition processes that are important for enantioselective catalysis or separation. Reported here are a series of 3-D open-framework materials with unusual integration of various homochiral and homohelical features, even in the bulk sample. ...[more]

PMID: 19053443

Similar Datasets

Absolute helicity induction in three-dimensional homochiral frameworks.

Project description:Three Co(II) isomers assembled from D-, or L-, or DL-camphorate together with achiral isonicotinate exhibit a clear relationship between chirality and helicity even though chiral molecules are not in the backbone of the helix: the absolute sense of helix made of achiral components is controlled by chains of metal and enantiopure chiral ligands running perpendicular to helix in two enantiomeric forms.

| S-EPMC2790072 | biostudies-literature

Chiral metal-macrocycle frameworks: supramolecular chirality induction and helicity inversion of the helical macrocyclic structures.

Project description:Porous molecular solids composed of discrete macrocycles/cages have great potential for catalysis, separation and sensing techniques. Dynamic structural transformation of the host building blocks, especially a helicity inversion responsive to chemical triggers, is central to upgrading the spatial functions. Here we have achieved the syntheses of homochiral porous molecular solids composed of helical metal macrocycles through supramolecular chirality induction to both enantiomorphic forms with the aid of two different enantiopure sugar-derived lactones in the crystallization process. Moreover, we found that the helicity of the macrocyclic skeletons can be inverted in the crystalline state only by changing the type of solvent. This finding would lead to dynamic control of space chirality in connection with optical resolution, chiral amplification and asymmetric reactions.

| S-EPMC5975940 | biostudies-literature

Competitive chiral induction in a 2D molecular assembly: Intrinsic chirality versus coadsorber-induced chirality.

Project description:Noncovalently introducing stereogenic information is a promising approach to embed chirality in achiral molecular systems. However, the interplay of the noncovalently introduced chirality with the intrinsic chirality of molecules or molecular aggregations has rarely been addressed. We report a competitive chiral expression of the noncovalent interaction-mediated chirality induction and the intrinsic stereogenic center-controlled chirality induction in a two-dimensional (2D) molecular assembly at the liquid/solid interface. Two enantiomorphous honeycomb networks are formed by the coassembly of an achiral 5-(benzyloxy)isophthalic acid (BIC) derivative and 1-octanol at the liquid/solid interface. The preferential formation of the globally homochiral assembly can be achieved either by using the chiral analog of 1-octanol, (S)-6-methyl-1-octanol, as a chiral coadsorber to induce chirality to the BIC assembly via noncovalent hydrogen bonding or by covalently linking a chiral center in the side chain of BIC. Both the chiral coadsorber and the intrinsically chiral BIC derivative can act as a chiral seeds to induce a preferred handedness in the assembly of the achiral BIC derivatives. Furthermore, the noncovalent interaction-mediated chirality induction can restrain or even overrule the manifestation of the intrinsic chirality of the BIC molecule and dominate the handedness of the 2D molecular coassembly. This study provides insight into the interplay of intrinsically chiral centers and external chiral coadsorbers in the chiral induction, transfer, and amplification processes of 2D molecular assembly.

| S-EPMC5669609 | biostudies-literature

Enantioseparation and chiral induction in Ag<sub>29</sub> nanoclusters with intrinsic chirality.

Project description:The optical activity of a metal nanocluster (NC) is induced either by an asymmetric arrangement of constituents or by a dissymmetric field of a chiral ligand layer. Herein, we unveil the origin of chirality in Ag29 NCs, which is attributed to the intrinsically chiral atomic arrangement. The X-ray crystal structure of a Ag29(BDT)12(TPP)4 NC (BDT: 1,3-benzenedithiol; TPP: triphenylphosphine) manifested the presence of intrinsic chirality in the outer shell capping the icosahedral achiral Ag13 core. The enantiomers of the Ag29(BDT)12(TPP)4 NC are separated by high-performance liquid chromatography (HPLC) using a chiral column for the first time, showing mirror-image circular dichroism (CD) spectra. The CD spectra are reproduced by time-dependent density functional theory (TDDFT) calculations based on enantiomeric Ag29 models with achiral 1,3-propanedithiolate ligands. The mechanism of chiral induction in the synthesis of Ag29(DHLA)12 (DHLA: α-dihydrolipoic acid) NCs with a chiral ligand system is further discussed with the aid of DFT calculations. The use of the enantiomeric DHLA ligand preferentially leads to a one-handed atomic arrangement which is more stable than the opposite one, inducing the enantiomeric excess in the population of intrinsically chiral Ag29 NCs with CD activity.

| S-EPMC8157427 | biostudies-literature

Can Polymer Helicity Affect Topological Chirality of Polymer Knots?

Project description:We investigate the effect of helicity in isolated polymers on the topological chirality of their knots with computer simulations. Polymers are described by generic worm-like chains (WLC), where helical conformations are promoted by chiral coupling between segments that are neighbors along the chain contour. The sign and magnitude of the coupling coefficient u determine the sense and strength of helicity. The corrugation of the helix is adjusted via the radius R of a spherical, hard excluded volume around each WLC segment. Open and compact helices are, respectively, obtained for R that is either zero or smaller than the length of the WLC bond, and R that is a few times larger than the bond length. We use a Monte Carlo algorithm to sample polymer conformations for different values of u, spanning the range from achiral polymers to chains with well-developed helices. Monitoring the average helix torsion and fluctuations of chiral order as a function of u, for two very different chain lengths, demonstrates that the coil-helix transition in this model is not a phase transition but a crossover. Statistical analysis of conformations forming the simplest chiral knots, 31, 51, and 52, demonstrates that topological mirror symmetry is broken─knots formed by helices with a given sense prefer one handedness over the other. For the 31 and 51 knots, positive helical sense favors positive handedness. Intriguingly, an opposite trend is observed for 52 knots, where positive helical sense promotes negative handedness. We argue that this special coupling between helicity and topological chirality stems from a generic mechanism: conformations where some of the knot crossings are found in "braids" formed by two tightly interwoven sections of the polymer.

| S-EPMC9948535 | biostudies-literature

Chiral Sulfoxide-Induced Single Turn Peptide α-Helicity.

Project description:Inducing α-helicity through side-chain cross-linking is a strategy that has been pursued to improve peptide conformational rigidity and bio-availability. Here we describe the preparation of small peptides tethered to chiral sulfoxide-containing macrocyclic rings. Furthermore, a study of structure-activity relationships (SARs) disclosed properties with respect to ring size, sulfur position, oxidation state, and stereochemistry that show a propensity to induce α-helicity. Supporting data include circular dichroism spectroscopy (CD), NMR spectroscopy, and a single crystal X-ray structure for one such stabilized peptide. Finally, theoretical studies are presented to elucidate the effect of chiral sulfoxides in inducing backbone α-helicity.

| S-EPMC5146914 | biostudies-literature

Homochiral crystallization of microporous framework materials from achiral precursors by chiral catalysis.

Project description:While it is not uncommon to form chiral crystals during crystallization, the formation of bulk porous homochiral materials from achiral building units is rare. Reported here is the homochiral crystallization of microporous materials through the chirality induction effect of natural alkaloids. The resulting material possesses permanent microporosity and has a uniform pore size of 9.3 A.

| S-EPMC2776631 | biostudies-literature

The Influence of Intrinsic Framework Flexibility on Adsorption in Nanoporous Materials.

Project description:For applications of metal-organic frameworks (MOFs) such as gas storage and separation, flexibility is often seen as a parameter that can tune material performance. In this work we aim to determine the optimal flexibility for the shape selective separation of similarly sized molecules (e.g., Xe/Kr mixtures). To obtain systematic insight into how the flexibility impacts this type of separation, we develop a simple analytical model that predicts a material's Henry regime adsorption and selectivity as a function of flexibility. We elucidate the complex dependence of selectivity on a framework's intrinsic flexibility whereby performance is either improved or reduced with increasing flexibility, depending on the material's pore size characteristics. However, the selectivity of a material with the pore size and chemistry that already maximizes selectivity in the rigid approximation is continuously diminished with increasing flexibility, demonstrating that the globally optimal separation exists within an entirely rigid pore. Molecular simulations show that our simple model predicts performance trends that are observed when screening the adsorption behavior of flexible MOFs. These flexible simulations provide better agreement with experimental adsorption data in a high-performance material that is not captured when modeling this framework as rigid, an approximation typically made in high-throughput screening studies. We conclude that, for shape selective adsorption applications, the globally optimal material will have the optimal pore size/chemistry and minimal intrinsic flexibility even though other nonoptimal materials' selectivity can actually be improved by flexibility. Equally important, we find that flexible simulations can be critical for correctly modeling adsorption in these types of systems.

| S-EPMC5399474 | biostudies-literature

Helicity-dependent photocurrents in the chiral Weyl semimetal RhSi.

Project description:Weyl semimetals are crystals in which electron bands cross at isolated points in momentum space. Associated with each crossing point (or Weyl node) is a topological invariant known as the Berry monopole charge. The circular photogalvanic effect (CPGE), whereby circular polarized light generates a helicity-dependent photocurrent, is a notable example of a macroscopic property that emerges directly from the topology of the Weyl semimetal band structure. Recently, it was predicted that the amplitude of the CPGE associated with optical transitions near a Weyl node is proportional to its monopole charge. In chiral Weyl systems, nodes of opposite charge are nondegenerate, opening a window of wavelengths where the CPGE resulting from uncompensated Berry charge can emerge. Here, we report measurements of CPGE in the chiral Weyl semimetal RhSi, revealing a CPGE response in an energy window that closes at 0.65 eV, in agreement with the predictions of density functional theory.

| S-EPMC7439497 | biostudies-literature

Polarity reveals intrinsic cell chirality.

Project description:Like blood neutrophils, dHL60 cells respond to a uniform concentration of attractant by polarizing in apparently random directions. How each cell chooses its own direction is unknown. We now find that an arrow drawn from the center of the nucleus of an unpolarized cell to its centrosome strongly predicts the subsequent direction of attractant-induced polarity: Of 60 cells that polarized in response to uniform f-Met-Leu-Phe (fMLP), 42 polarized to the left of this arrow, 6 polarized to the right, and 12 polarized directly toward or away from the centrosome. To investigate this directional bias we perturbed a regulatory pathway, downstream of Cdc42 and partitioning-defective 6 (Par6), which controls centrosome orientation relative to polarity of other cells. Dominant negative Par6 mutants block polarity altogether, as previously shown for disrupting Cdc42 activity. Cells remain able to polarize, but without directional bias, if their microtubules are disrupted with nocodazole, or they express mutant proteins that interfere with activities of PKCzeta or dynein. Expressing constitutively active glycogen synthase kinase 3beta (GSK3beta) causes cells to polarize preferentially to the right. Distributions of most of these polarity regulators localize to the centrosome but show no left-right asymmetry before polarization. Together, these findings suggest that an intrinsically chiral structure, perhaps the centrosome, serves as a template for directing polarity in the absence of spatial cues. Such a template could help to determine left-right asymmetry and planar polarity in development.

| S-EPMC1890488 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data