Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Non-equilibrium cobalt(iii) "click" capsules.

ABSTRACT: Cobalt(iii) tetrahedral capsules have been prepared using an assembly-followed-by-oxidation protocol from a cobalt(ii) precursor and a readily derivatizable pyridyl-triazole ligand system. Experiments designed to probe the constitutional dynamics show that these architectures are in a non-equilibrium state. A preliminary investigation into the host-guest chemistry of a water-soluble derivative shows it can bind and differentiate a range of different neutral organic molecules. The stability of this ensemble also permits the study of guest-binding at high salt concentrations.

SUBMITTER: Symmers PR

PROVIDER: S-EPMC5494537 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Non-equilibrium cobalt(iii) "click" capsules.

Symmers P R PR Burke M J MJ August D P DP Thomson P I T PIT Nichol G S GS Warren M R MR Campbell C J CJ Lusby P J PJ

Chemical science 20141007 1

Cobalt(iii) tetrahedral capsules have been prepared using an assembly-followed-by-oxidation protocol from a cobalt(ii) precursor and a readily derivatizable pyridyl-triazole ligand system. Experiments designed to probe the constitutional dynamics show that these architectures are in a non-equilibrium state. A preliminary investigation into the host-guest chemistry of a water-soluble derivative shows it can bind and differentiate a range of different neutral organic molecules. The stability of th ...[more]

PMID: 28706638

Similar Datasets

Tris(ethyl-enediamine)-cobalt(III) diformatodioxalatoindate(III) dihydrate.

Project description:In the cation of the title compound, [Co(C(2)H(8)N(2))(3)][In(C(2)O(4))(2)(CHO(2))(2)]·2H(2)O, the Co-N bond lengths lie in the range 1.960?(5)-1.997?(5)?Å. In the anion, the In(III) atom is coordin-ated by four O atoms from two oxalato ligands and two O atoms from two formato ligands in a distorted octa-hedral geometry. Inter-molecular O-H?O and N-H?O hydrogen bonds form an extensive hydrogen-bonding network, which link the cations, anions and water mol-ecules into three-dimensional structure.

| S-EPMC3089116 | biostudies-literature

Bis(diethyl-enetriamine)-cobalt(III) hexa-chloridoindate(III).

Project description:The title compound, [Co(C(4)H(13)N(3))(2)][InCl(6)], was synthesized under hydro-thermal conditions. In the cation, the Co-N bond lengths lie in the range 1.967?(2)-1.9684?(15)?Å. In the anion, the In(III) atom is coordinated by six Cl atoms resulting in a slightly distorted octa-hedral geometry. Both metal atoms are located on special positions of site symmetry 2/m. Furthermore, one Cl atom and one N atom are located on a mirror plane. N-H?Cl hydrogen bonds between cations and anions consolidate the crystal packing.

| S-EPMC3120378 | biostudies-literature

Redox Interconversion between Cobalt(III) Thiolate and Cobalt(II) Disulfide Compounds.

Project description:The redox interconversion between Co(III) thiolate and Co(II) disulfide compounds has been investigated experimentally and computationally. Reactions of cobalt(II) salts with disulfide ligand L1SSL1 (L1SSL1 = di-2-(bis(2-pyridylmethyl)amino)-ethyl disulfide) result in the formation of either the high-spin cobalt(II) disulfide compound [CoII2(L1SSL1)Cl4] or a low-spin, octahedral cobalt(III) thiolate compound, such as [CoIII(L1S)(MeCN)2](BF4)2. Addition of thiocyanate anions to a solution containing the latter compound yielded crystals of [CoIII(L1S)(NCS)2]. The addition of chloride ions to a solution of [CoIII(L1S)(MeCN)2](BF4)2 in acetonitrile results in conversion of the cobalt(III) thiolate compound to the cobalt(II) disulfide compound [CoII2(L1SSL1)Cl4], as monitored with UV-vis spectroscopy; subsequent addition of AgBF4 regenerates the Co(III) compound. Computational studies show that exchange by a chloride anion of the coordinated acetonitrile molecule or thiocyanate anion in compounds [CoIII(L1S)(MeCN)2]2+ and [CoIII(L1S)(NCS)2] induces a change in the character of the highest occupied molecular orbitals, showing a decrease of the contribution of the p orbital on sulfur and an increase of the d orbital on cobalt. As a comparison, the synthesis of iron compounds was undertaken. X-ray crystallography revealed that structure of the dinuclear iron(II) disulfide compound [FeII2(L1SSL1)Cl4] is different from that of cobalt(II) compound [CoII2(L1SSL1)Cl4]. In contrast to cobalt, reaction of ligand L1SSL1 with [Fe(MeCN)6](BF4)2 did not yield the expected Fe(III) thiolate compound. This work is an unprecedented example of redox interconversion between a high-spin Co(II) disulfide compound and a low-spin Co(III) thiolate compound triggered by the nature of the anion.

| S-EPMC6150680 | biostudies-literature

Aqua-bromidobis(dimethyl-glyoximato)cobalt(III).

Project description:In the title complex, [CoBr(C(4)H(7)N(2)O(2))(2)(H(2)O)], a crystallo-graphic mirror plane bis-ects the mol-ecule, perpendicular to the glyoximate ligands. The geometry around the cobalt(III) atom is approximately octa-hedral with the four glyoximate N atoms forming the square base. A bromide ion and the O atom of a water mol-ecule occupy the remaining coordination sites. The N-Co-N bite angles are 82.18?(4) and 80.03?(16)°. The glyoximate moieties form strong intra-molecular O-H?O hydrogen bonds. The coordinated water mol-ecule forms an inter-molecular O-H?O hydrogen bond with a glyoximate O atom, thereby generating supra-molecular chains parallel to [010].

| S-EPMC3099747 | biostudies-literature

Local non-equilibrium thermodynamics.

Project description:Local Shannon entropy lies at the heart of modern thermodynamics, with much discussion of trajectory-dependent entropy production. When taken at both boundaries of a process in phase space, it reproduces the second law of thermodynamics over a finite time interval for small scale systems. However, given that entropy is an ensemble property, it has never been clear how one can assign such a quantity locally. Given such a fundamental omission in our knowledge, we construct a new ensemble composed of trajectories reaching an individual microstate, and show that locally defined entropy, information, and free energy are properties of the ensemble, or trajectory-independent true thermodynamic potentials. We find that the Boltzmann-Gibbs distribution and Landauer's principle can be generalized naturally as properties of the ensemble, and that trajectory-free state functions of the ensemble govern the exact mechanism of non-equilibrium relaxation.

| S-EPMC4296294 | biostudies-literature

M-O Bonding Beyond the Oxo Wall: Spectroscopy and Reactivity of Cobalt(III)-Oxyl and Cobalt(III)-Oxo Complexes.

Project description:Terminal oxo complexes of late transition metals are frequently proposed reactive intermediates. However, they are scarcely known beyond Group 8. Using mass spectrometry, we prepared and characterized two such complexes: [(N4Py)CoIII (O)]+ (1) and [(N4Py)CoIV (O)]2+ (2). Infrared photodissociation spectroscopy revealed that the Co-O bond in 1 is rather strong, in accordance with its lack of chemical reactivity. On the contrary, 2 has a very weak Co-O bond characterized by a stretching frequency of ≤659 cm-1 . Accordingly, 2 can abstract hydrogen atoms from non-activated secondary alkanes. Previously, this reactivity has only been observed in the gas phase for small, coordinatively unsaturated metal complexes. Multireference ab-initio calculations suggest that 2, formally a cobalt(IV)-oxo complex, is best described as cobalt(III)-oxyl. Our results provide important data on changes to metal-oxo bonding behind the oxo wall and show that cobalt-oxo complexes are promising targets for developing highly active C-H oxidation catalysts.

| S-EPMC6618258 | biostudies-literature

Hexakis(dimethyl sulfoxide-?O)cobalt(III) trinitrate.

Project description:The metal atom of the title salt, [Co(C(2)H(6)OS)(6)](NO(3))(3), is coordinated by six dimethyl sulfoxide mol-ecules in an octa-hedral geometry. The metal atom lies on a special position of site symmetry. One of the nitrate ions lies on a special position of 3 site symmetry and the other independent ion is disordered about a special position of site symmetry.

| S-EPMC2980005 | biostudies-literature

Aerobic Oxidation Reactivity of Well-Defined Cobalt(II) and Cobalt(III) Aminophenol Complexes.

Project description:This paper describes the synthesis and reactivity studies of three cobalt complexes bearing aminophenol-derived ligands without nitrogen substitution: CoII(tBu2APH)2(tBu2AP)2 (1), CoIII2(tBu2APH)2(tBu2AP)2(μ-tBu2BAP)2 (2), and CoIII(tBu2AP)3 (3), where tBu2APH = 2-amino-4,6-di-tert-butylphenol, tBu2AP = 2-amino-4,6-di-tert-butylphenolate, and μ-tBu2BAP = bridging 2-amido-4,6-di-tert-butylphenolate. Stoichiometric reactivity studies of these well-defined complexes demonstrate the catalytic competency of both cobalt(II) and cobalt(III) complexes in the aerobic oxidative cyclization of tBu2APH with tert-butylisonitrile. Reactions with O2 reveal the aerobic oxidation of the cobalt(II) complex 1 to generate the cobalt(III) species 2 and 3. UV-visible time-course studies and electron paramagnetic resonance spectroscopy indicate that this oxidation proceeds through a ligand-based radical intermediate. These studies represent the first example of well-defined cobalt aminophenol complexes that participate in catalytic aerobic oxidation reactions and highlight a key role for a ligand radical in the oxidation sequence.

| S-EPMC9328405 | biostudies-literature

Comparison of DNA decatenation by Escherichia coli topoisomerase IV and topoisomerase III: implications for non-equilibrium topology simplification.

Project description:Type II topoisomerases are essential enzymes that regulate DNA topology through a strand-passage mechanism. Some type II topoisomerases relax supercoils, unknot and decatenate DNA to below thermodynamic equilibrium. Several models of this non-equilibrium topology simplification phenomenon have been proposed. The kinetic proofreading (KPR) model postulates that strand passage requires a DNA-bound topoisomerase to collide twice in rapid succession with a second DNA segment, implying a quadratic relationship between DNA collision frequency and relaxation rate. To test this model, we used a single-molecule assay to measure the unlinking rate as a function of DNA collision frequency for Escherichia coli topoisomerase IV (topo IV) that displays efficient non-equilibrium topology simplification activity, and for E. coli topoisomerase III (topo III), a type IA topoisomerase that unlinks and unknots DNA to equilibrium levels. Contrary to the predictions of the KPR model, topo IV and topo III unlinking rates were linearly related to the DNA collision frequency. Furthermore, topo III exhibited decatenation activity comparable with that of topo IV, supporting proposed roles for topo III in DNA segregation. This study enables us to rule out the KPR model for non-equilibrium topology simplification. More generally, we establish an experimental approach to systematically control DNA collision frequency.

| S-EPMC3632123 | biostudies-literature

Equilibrium and non-equilibrium furanose selection in the ribose isomerisation network.

Project description:The exclusive presence of β-D-ribofuranose in nucleic acids is still a conundrum in prebiotic chemistry, given that pyranose species are substantially more stable at equilibrium. However, a precise characterisation of the relative furanose/pyranose fraction at temperatures higher than about 50 °C is still lacking. Here, we employ a combination of NMR measurements and statistical mechanics modelling to predict a population inversion between furanose and pyranose at equilibrium at high temperatures. More importantly, we show that a steady temperature gradient may steer an open isomerisation network into a non-equilibrium steady state where furanose is boosted beyond the limits set by equilibrium thermodynamics. Moreover, we demonstrate that nonequilibrium selection of furanose is maximum at optimal dissipation, as gauged by the temperature gradient and energy barriers for isomerisation. The predicted optimum is compatible with temperature drops found in hydrothermal vents associated with extremely fresh lava flows on the seafloor.

| S-EPMC8115175 | 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