Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Dynamic Pseudorotaxane Crystals Containing Metallocene Complexes.

ABSTRACT: Molecular machines and switches composed of flexible pseudorotaxanes respond to external stimuli, transducing incident energy into mechanical motions. This study presents thermo- and photoresponsive dynamic pseudorotaxane crystals composed of axle molecules containing ferrocene or ruthenocene groups threaded through dibenzo[24]crown-8 ether rings. The ruthenocene-containing pseudorotaxane exhibits a crystal-to-crystal thermal phase transition at 86?°C, which is much lower than that of the ferrocene-containing pseudorotaxane (128?°C). Single-crystal X-ray crystallography at various temperatures reveals the details of the structural changes, and shows that the bulky ruthenocene provides distortion in the pseudorotaxane structure to facilitate twisting of the axle molecule. A mixed ferrocene and ruthenocene pseudorotaxane crystal is applied to photomechanical conversion under 405?nm laser irradiation at 85?°C and provides a lifting force 6,400-times the weight of the crystal itself upon phase transition.

SUBMITTER: Chen KJ

PROVIDER: S-EPMC5660174 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Dynamic Pseudorotaxane Crystals Containing Metallocene Complexes.

Chen Kai-Jen KJ Chen Pei-Lin PL Horie Masaki M

Scientific reports 20171027 1

Molecular machines and switches composed of flexible pseudorotaxanes respond to external stimuli, transducing incident energy into mechanical motions. This study presents thermo- and photoresponsive dynamic pseudorotaxane crystals composed of axle molecules containing ferrocene or ruthenocene groups threaded through dibenzo[24]crown-8 ether rings. The ruthenocene-containing pseudorotaxane exhibits a crystal-to-crystal thermal phase transition at 86 °C, which is much lower than that of the ferroc ...[more]

PMID: 29079834

Similar Datasets

Crystal structures of metallocene complexes with uranium-germanium bonds.

Project description:The first structural examples of complexes with uranium-germanium bonds are presented, namely, bis-[3,5-bis-(tri-fluoro-meth-yl)phenyl-2κC 1](hydrido-2κH)(iodido-1κI)bis-[1,1(η5)-penta-methyl-cyclo-penta-dien-yl]germaniumuranium(Ge-U), [GeU(C10H15)2(C8H3F6)2HI], and bis-[3,5-bis-(tri-fluoro-meth-yl)phenyl-2κC 1](fluorido-1κI)(hydrido-2κH)bis-[1,1(η5)-penta-methyl-cyclo-penta-dien-yl]germaniumuranium(Ge-U), [GeU(C10H15)2(C8H3F6)2FH]. The two complexes both have a long U-Ge bond [distances of 3.0428 (7) and 3.0524 (7) Å].

| S-EPMC8647732 | biostudies-literature

Redox-Rich Metallocene Tetrazene Complexes: Synthesis, Structure, Electrochemistry, and Catalysis.

Project description:Thermal or photochemical metal-centered cycloaddition reactions of azidocobaltocenium hexafluoridophosphate or azidoferrocene with (cyclooctadiene)(cyclopentadienyl)cobalt(I) afforded the first metallocenyl-substituted tetrazene cyclopentadienyl cobalt complexes together with azocobaltocenium or azoferrocene as side products. The trimetallic CpCo compounds are highly conjugated, colored, and redox-active metallo-aromatic compounds, as shown by their spectroscopic, structural, and electrochemical properties. The CpCo-tetrazenido complex with two terminally appended cobaltocene units catalyzes electrochemical proton reduction from acetic acid at a mild overpotential (0.35 V). Replacing cobaltocene with ferrocene moieties rendered the complex inactive toward catalysis.

| S-EPMC6437651 | biostudies-literature

Synthesis and Antitumor Activity of New Group 3 Metallocene Complexes.

Project description:The quest for alternative drugs with respect to the well-known cis-platin and its derivatives, which are still used in more than 50% of the treatment regimens for patients suffering from cancer, is highly needed. In this context, organometallic compounds, which are defined as metal complexes containing at least one direct covalent metal-carbon bond, have recently been found to be promising anticancer drug candidates. A series of new metallocene complexes with scandium, yttrium, and neodymium have been prepared and characterized. Some of these compounds show a very interesting anti-proliferative activity in triple negative breast cancer cell line (MDA.MB231) and the non-hormone sensitive prostate cancer cell line (DU145). Moreover, the interaction of some of them with biological membranes, evaluated using liposomes as bio-membrane mimetic model systems, seems to be relevant. The biological activity of these compounds, particularly those based on yttrium, already effective at low concentrations on both cancer cell lines, should be taken into account with regard to new therapeutic approaches in anticancer therapy.

| S-EPMC6154682 | biostudies-literature

A rare earth metallocene containing a 2,2'-azopyridyl radical anion.

Project description:Introducing spin onto organic ligands that are coordinated to rare earth metal ions allows direct exchange with metal spin centres. This is particularly relevant for the deeply buried 4f-orbitals of the lanthanide ions that can give rise to unparalleled magnetic properties. For efficacy of exchange coupling, the donor atoms of the radical ligand require high-spin density. Such molecules are extremely rare owing to their reactive nature that renders isolation and purification difficult. Here, we demonstrate that a 2,2'-azopyridyl (abpy) radical (S = 1/2) bound to the rare earth metal yttrium can be realized. This molecule represents the first rare earth metal complex containing an abpy radical and is unambigously characterized by X-ray crystallography, NMR, UV-Vis-NIR, and IR spectroscopy. In addition, the most stable isotope 89Y with a natural abundance of 100% and a nuclear spin of ½ allows an in-depth analysis of the yttrium-radical complex via EPR and HYSCORE spectroscopy. Further insight into the electronic ground state of the radical azobispyridine-coordinated metal complex was realized through unrestricted DFT calculations, which suggests that the unpaired spin density of the SOMO is heavily localized on the azo and pyridyl nitrogen atoms. The experimental results are supported by NBO calculations and give a comprehensive picture of the spin density of the azopyridyl ancillary ligand. This unexplored azopyridyl radical anion in heavy element chemistry bears crucial implications for the design of molecule-based magnets particularly comprising anisotropic lanthanide ions.

| S-EPMC8634996 | biostudies-literature

Metallocene-Containing Homopolymers and Heterobimetallic Block Copolymers via Photoinduced RAFT Polymerization.

Project description:We report the synthesis of cationic cobaltocenium and neutral ferrocene containing homopolymers mediated by photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization with a photocatalyst fac-[Ir(ppy)3]. The homopolymers were further used as macromolecular chain transfer agents to synthesize diblock copolymers via chain extension. Controlled/"living" feature of photoinduced RAFT polymerization was confirmed by kinetic studies even without prior deoxygenation. A light switch between ON and OFF provided a spatiotemporal control of polymerization.

| S-EPMC5739086 | biostudies-literature

Identification and dynamic changes of RNAs isolated from RALY-containing ribonucleoprotein complexes.

Project description:RALY is a member of the heterogeneous nuclear ribonucleoprotein family (hnRNP), a large family of RNA-binding proteins involved in many aspects of RNA metabolism. Although RALY interactome has been recently characterized, a comprehensive global analysis of RALY-associated RNAs is lacking and the biological function of RALY remains elusive. Here, we performed RIP-seq analysis to identify RALY interacting RNAs and assessed the role of RALY in gene expression. We demonstrate that RALY binds specific coding and non-coding RNAs and associates with translating mRNAs of mammalian cells. Among the identified transcripts, we focused on ANXA1 and H1FX mRNAs, encoding for Annexin A1 and for the linker variant of the histone H1X, respectively. Both proteins are differentially expressed by proliferating cells and are considered as markers for tumorigenesis. We demonstrate that cells lacking RALY expression exhibit changes in the levels of H1FX and ANXA1 mRNAs and proteins in an opposite manner. We also provide evidence for a direct binding of RALY to the U-rich elements present within the 3΄UTR of both transcripts. Thus, our results identify RALY as a poly-U binding protein and as a regulator of H1FX and ANXA1 in mammalian cells.

| S-EPMC5499869 | biostudies-literature

Dynamic ordering transitions of liquid crystals driven by interfacial complexes formed between polyanions and amphiphilic polyamines.

Project description:We report the design of an amphiphilic polyamine (polymer 1) based on poly(2-alkenyl azlactone) that strongly couples the formation of polyelectrolyte complexes at aqueous/liquid crystal (LC) interfaces to ordering transitions in the LC. We demonstrate that the addition of a strong anionic polyelectrolyte to aqueous solutions in contact with polymer 1-laden LC interfaces (prepared by Langmuir-Schaefer transfer of monolayers of polymer 1 onto micrometer-thick films of nematic LC) triggers ordering transitions in the LCs. We further demonstrate that changes in the ordering of the LCs (i) are driven by electrostatic interactions between the polyelectrolytes, (ii) involve multivalent interactions between the polyelectrolytes, and (iii) are triggered by reorganization of the hydrophobic side chains of amphiphilic polymer 1 upon formation of the interfacial complexes. The results presented in this paper lead us to conclude that ordering transitions in LCs can be used to provide insights into the structure and dynamics of interfacial complexes formed between polyelectrolytes.

| S-EPMC3245549 | biostudies-literature

Macromolecular complexes in crystals and solutions.

Project description:This paper presents a discussion of existing methods for the analysis of macromolecular interactions and complexes in crystal packing. Typical situations and conditions where wrong answers may be obtained in the course of ordinary procedures are presented and discussed. The more general question of what the relationship is between natural (in-solvent) and crystallized assemblies is discussed and researched. A computational analysis suggests that weak interactions with K(d) ? 100 µM have a considerable chance of being lost during the course of crystallization. In such instances, crystal packing misrepresents macromolecular complexes and interactions. For as many as 20% of protein dimers in the PDB the likelihood of misrepresentation is estimated to be higher than 50%. Given that weak macromolecular interactions play an important role in many biochemical processes, these results suggest that a complementary noncrystallographic study should be always conducted when inferring structural aspects of weakly bound complexes.

| S-EPMC3069753 | biostudies-literature

Isolation of C1 through C4 derivatives from CO using heteroleptic uranium(iii) metallocene aryloxide complexes.

Project description:The conversion of C1 feedstock molecules such as CO into commodity chemicals is a desirable, but challenging, endeavour. When the U(iii) complex, [(C5Me5)2U(O-2,6- t Bu2-4-MeC6H2)], is exposed to 1 atm of CO, only coordination is observed by IR spectroscopy as well as X-ray crystallography, unveiling a rare structurally characterized f element carbonyl. However, using [(C5Me5)2(MesO)U (THF)], Mes = 2,4,6-Me3C6H2, reaction with CO forms the bridging ethynediolate species, [{(C5Me5)2(MesO)U}2(μ2-OCCO)]. While ethynediolate complexes are known, their reactivity has not been reported in much detail to afford further functionalization. For example, addition of more CO to the ethynediolate complex with heating forms a ketene carboxylate, [{(C5Me5)2(MesO)U}2(μ 2:κ 2:η 1-C3O3)], which can be further reacted with CO2 to yield a ketene dicarboxylate complex, [{(C5Me5)2(MesO)U}2(μ 2:κ 2:κ 2-C4O5)]. Since the ethynediolate showed reactivity with more CO, we explored its reactivity further. A [2 + 2] cycloaddition is observed with diphenylketene to yield [{(C5Me5)2U}2(OC(CPh2)C([double bond, length as m-dash]O)CO)] with concomitant formation of [(C5Me5)2U(OMes)2]. Surprisingly, reaction with SO2 shows rare S-O bond cleavage to yield the unusual [(O2CC(O)(SO)]2- bridging ligand between two U(iv) centres. All complexes have been characterized using spectroscopic and structural methods, and the reaction of the ethynediolate with CO to form the ketene carboxylate has been investigated computationally as well as the reaction with SO2.

| S-EPMC9945253 | biostudies-literature

Poly(Ethylene Glycol)/β-Cyclodextrin Pseudorotaxane Complexes as Sustainable Dispersing and Retarding Materials in a Cement-Based Mortar.

Project description:Pseudorotaxane complexes between β-CD and mPEG derivatives bearing a carboxylic acid function (mPEG-COOH) were synthesized and investigated for their dispersing properties in a cement-based mortar. The formation of mPEG-COOH derivatives and their pseudorotaxanes was investigated by 1D nuclear magnetic resonance, diffusion ordered spectroscopy, and thermogravimetric analysis experiments. Mortar tests clearly indicate that mPEG-COOH@β-CD-interpenetrated supramolecules show excellent dispersing abilities. In addition, the supramolecular complexes show a retarding effect, analogously to other known β-CD-based superplasticizers in which the β-CD is covalently grafted on a polymeric backbone.

| S-EPMC8154154 | 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