Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Towards Covalent Photosensitizer-Polyoxometalate Dyads-Bipyridyl-Functionalized Polyoxometalates and Their Transition Metal Complexes.

ABSTRACT: A triol-functionalized 2,2'-bipyridine (bpy) derivative has been synthesized and used for the tris-alkoxylation of polyoxometalate (POM) precursors. The resultant POM-bpy conjugates of the Wells-Dawson- and Anderson-type feature a C-C bond as a linkage between the POM and bpy fragments. This structural motif is expected to increase the hydrolytic stability of the compounds. This is of particular relevance with respect to the application of POM-bpy metal complexes, as photocatalysts, in the hydrogen-evolution reaction (HER) in an aqueous environment. Accordingly, Rh(III) and Ir(III) complexes of the POM-bpy ligands have been prepared and characterized. These catalyst-photosensitizer dyads have been analyzed with respect to their electrochemical and photophysical properties. Cyclic and square-wave voltammetry, as well as UV/vis absorption and emission spectroscopy, indicated a negligible electronic interaction of the POM and metal-complex subunits in the ground state. However, emission-quenching experiments suggested an efficient intramolecular electron-transfer process from the photo-excited metal centers to the POM units to account for the non-emissive nature of the dyads (thus, suggesting a strong interaction of the subunits in the excited state). In-depth photophysical investigations, as well as a functional characterization, i.e., the applicability in the HER reaction, are currently ongoing.

SUBMITTER: Winter A

PROVIDER: S-EPMC6943497 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Oxidative quenching within photosensitizer-acceptor dyads based on bis(bidentate) phosphine-connected osmium(II) bipyridyl light absorbers and reactive metal sites.

Project description:For the first time oxidative quenching of OsP2N4 chromophores by reactive PtII or PdII sites containing cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) is directly observed despite the presence of a saturated cyclobutane backbone "bridge". This dramatic effect is measured as a sudden temperature-dependent onset of a reduction in phosphorescence lifetime in [Os(bpy)2(dppcb)MCl2](SbF6)2 (M = Pt, 1; Pd, 2). The appearance of this additional energy release is not detectable in [Os(bpy)2(dppcbO2)](PF6)2 (3), where dppcbO2 is cis, trans, cis-1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane. Obviously, the square-planar metal centers in 1 and 2 are responsible for this effect. In line with these observations, the emission quantum yields at room temperature for 1 and 2 are drastically reduced compared with 3. Since this luminescence quenching implies strong intramolecular interaction between the OsII excited states and the acceptor sites and depends on the metal?metal distances, also the single crystal X-ray structures of 1-3 are given.

| S-EPMC3587338 | biostudies-literature

HIV-1 protease inhibition potential of functionalized polyoxometalates.

Project description:Polyoxometalates (POMs) are interesting biomedical agents due to their versatile anticancer and antiviral properties, such as remarkable anti-HIV activity. Although POMs are tunable and easily accessible inorganic drug prototypes in principle, their full potential can only be tapped by enhancing their biocompatibility, for example, through organic functionalization. We have therefore investigated the HIV-1 protease inhibition potential of functionalized Keggin- and Dawson-type POMs with organic side chains. Their inhibitory performance was furthermore compared to other POM types, and the buffer dependence of the results is discussed. In addition, chemical shift mapping NMR experiments were performed to exclude POM-substrate interactions. Whereas the introduction of organic side chains into POMs is a promising approach in principle, the influence of secondary effects on the reaction system also merits detailed investigation.

| S-EPMC7126215 | biostudies-literature

Rapid photoinduced charge injection into covalent polyoxometalate-bodipy conjugates.

Project description:Controlled design of photoactive hybrids would provide highly active materials for solar energy conversion and photo(electro) catalysis. We describe the kinetics of photoinduced electron transfer in a series of photoactive hybrids based on Keggin-type polyoxometalates (POMs) covalently grafted to bodipy photosensitizers. We show how the electronic properties and corresponding dynamics of these hybrids can be readily tuned by varying the POM metal ion, the anchoring functionalization and the spacer length. Ultrafast visible and IR transient absorption spectroscopy, supported by spectroelectrochemical measurements, reveals that photoinduced electron transfer from the bodipy chromophore to the organosilyl POM derivative occurs as rapidly as ? = 54 ps to generate a long-lived (? = 4.8 ns) charge-separated (CS) state, making this system appropriate for applications in photoelectrochemical devices.

| S-EPMC6048759 | biostudies-literature

Dyes Adsorption Behavior of Fe3O4 Nanoparticles Functionalized Polyoxometalate Hybrid.

Project description:The magnetic adsorbent, Fe3O4@[Ni(HL)2]2H2[P2Mo5O23]·2H2O (Fe3O4@1), is synthesized by employing the nanoparticles Fe3O4 and polyoxometalate hybrid 1. Zero-field-cooled (ZFC) and field-cooled (FC) curves show that the blocking temperature of Fe3O4@1 was at 120 K. Studies of Fe3O4@1 removing cationic and anionic dyes from water have been explored. The characterization of Fe3O4@1, effects of critical factors such as dosage, the concentration of methylene blue (MB), pH, adsorption kinetics, isotherm, the removal selectivity of substrate and the reusability of Fe3O4@1 were assessed. The magnetic adsorbent displayed an outstanding removal activity for the cationic dye at a broad range of pH. The adsorption kinetics and isotherm models revealed that the adsorption process of Fe3O4@1 was mainly governed via chemisorption. The maximum capacity of Fe3O4@1 adsorbing substance was 41.91 mg g-1. Furthermore, Fe3O4@1 showed its high stability by remaining for seven runs of the adsorption-desorption process with an effective MB removal rate, and could also be developed as a valuable adsorbent for dyes elimination from aqueous system.

| S-EPMC6749234 | biostudies-literature

Covalent Linkage of BODIPY-Photosensitizers to Anderson-Type Polyoxometalates Using CLICK Chemistry.

Project description:The covalent attachment of molecular photosensitizers (PS) to polyoxometalates (POMs) opens new pathways to PS-POM dyads for light-driven charge-transfer and charge-storage. Here, we report a synthetic route for the covalent linkage of BODIPY-dyes to Anderson-type polyoxomolybdates by using CLICK chemistry (i. e. copper-catalyzed azide-alkyne cycloaddition, CuAAC). Photophysical properties of the dyad were investigated by combined experimental and theoretical methods and highlight the role of both sub-components for the charge-separation properties. The study demonstrates how CLICK chemistry can be used for the versatile linkage of organic functional units to molecular metal oxide clusters.

| S-EPMC9292257 | biostudies-literature

New Insights on the Interaction of Phenanthroline Based Ligands and Metal Complexes and Polyoxometalates with Duplex DNA and G-Quadruplexes.

Project description:This work provides new insights from our team regarding advances in targeting canonical and non-canonical nucleic acid structures. This modality of medical treatment is used as a form of molecular medicine specifically against the growth of cancer cells. Nevertheless, because of increasing concerns about bacterial antibiotic resistance, this medical strategy is also being explored in this field. Up to three strategies for the use of DNA as target have been studied in our research lines during the last few years: (1) the intercalation of phenanthroline derivatives with duplex DNA; (2) the interaction of metal complexes containing phenanthroline with G-quadruplexes; and (3) the activity of Mo polyoxometalates and other Mo-oxo species as artificial phosphoesterases to catalyze the hydrolysis of phosphoester bonds in DNA. We demonstrate some promising computational results concerning the favorable interaction of these small molecules with DNA that could correspond to cytotoxic effects against tumoral cells and microorganisms. Therefore, our results open the door for the pharmaceutical and medical applications of the compounds we propose.

| S-EPMC8397986 | biostudies-literature

Efficient Blue Phosphorescence in Gold(I)-Acetylide Functionalized Coinage Metal Bis(amidinate) Complexes.

Project description:The synthesis of linear symmetric ethynyl- and acetylide-amidinates of the coinage metals is presented. Starting with the desilylation of the complexes [{Me3 SiC?CC(NDipp)2 }2 M2 ] (Dipp=2,6-diisopropylphenyl) (M=Cu, Au) it is demonstrated that this compound class is suitable to serve as a versatile metalloligand. Deprotonation with n-butyllithium and subsequent salt metathesis reactions yield symmetric tetranuclear gold(I) acetylide complexes of the form [{(PPh3 )AuC?CC(NDipp)2 }2 M2 ] (M=Cu, Au). The corresponding Ag complex [{(PPh3 )AuC?CC(NDipp)2 }2 Ag2 ] was obtained by a different route via metal rearrangement. All compounds show bright blue or blue-green microsecond long phosphorescence in the solid state, hence their photophysical properties were thoroughly investigated in a temperature range of 20-295?K. Emission quantum yields of up to 41?% at room temperature were determined. Furthermore, similar emissions with quantum yields of 15?% were observed for the two most brightly luminescent complexes in thf solution.

| S-EPMC7756867 | biostudies-literature

A Phosphine Functionalized β-Diketimine Ligand for the Synthesis of Manifold Metal Complexes.

Project description:A bis(diphenyl)-phosphine functionalized β-diketimine (PNac-H) was synthesized as a flexible ligand for transition metal complexes. The newly designed ligand features symmetrically placed phosphine moieties around a β-diketimine unit, forming a PNNP-type pocket. Due to the hard and soft donor atoms (N vs. P) the ligand can stabilize various coordination polyhedra. A complete series ranging from coordination numbers 2 to 6 was realized. Linear, trigonal planar, square planar, tetrahedral, square pyramidal, and octahedral coordination arrangements containing the PNac-ligand around the metal center were observed by using suitable metal sources. Hereby, PNac-H or its anion PNac- acts as mono-, bi- and tetradendate ligand. Such a broad flexibility is unusual for a rigid tetradentate system. The structural motifs were realized by treatment of PNac-H with a series of late transition metal precursors, for example, silver, gold, nickel, copper, platinum, and rhodium. The new complexes have been fully characterized by single crystal X-ray diffraction, NMR, IR, UV/Vis spectroscopy, mass spectrometry as well as elemental analysis. Additionally, selected complexes were investigated regarding their photophysical properties. Thus, PNac-H proved to be an ideal ligand platform for the selective coordination and stabilization of various metal ions in diverse polyhedra and oxidation states.

| S-EPMC7693294 | biostudies-literature

Immobilization of Polyoxometalate in the Metal-Organic Framework rht-MOF-1: Towards a Highly Effective Heterogeneous Catalyst and Dye Scavenger.

Project description:A series of three remarkable complexes [PMo12O40]@[Cu6O(TZI)3(H2O)9]4·OH·31H2O (H3TZI?=?5-tetrazolylisophthalic acid; denoted as HLJU-1, HLJU?=?Heilongjiang University), [SiMo12O40]@[Cu6O(TZI)3(H2O)9]4·32H2O (denoted as HLJU-2), and [PW12O40]@[Cu6O(TZI)3(H2O)6]4·OH·31H2O (denoted as HLJU-3) have been isolated by using simple one-step solvothermal reaction of copper chloride, 5-tetrazolylisophthalic acid (H3TZI), and various Keggin-type polyoxometalates (POMs), respectively. Crystal analysis of HLJU 1-3 reveals that Keggin-type polyoxoanions have been fitted snuggly in the cages of rht-MOF-1 (MOF: metal-organic framework) with large cell volume in a range of 87968-88800?Å(3) and large pore volume of about 68%. HLJU 1-3 exhibit unique catalytic selectivity and reactivity in the oxidation of alkylbenzene with environmental benign oxidant under mild condition in aqueous phase as well as the uptake capacity towards organic pollutants in aqueous solution.

| S-EPMC4860640 | biostudies-literature

Ternary Porphyrinato Hf(IV) and Zr(IV) - Polyoxometalate Complexes.

Project description:We report a facile, high yield synthesis and characterization of discrete, ternary porphyrin-metal-polyoxometalate (Por-M-POM) complexes where a group (IV) transition metal ion is bound both to the porphyrin core and to the lacunary site of a Keggin POM, PW(11)O(39) (-7). The remarkably robust complexes exploit the fact that Hf(IV) and Zr(IV) are 7-8 coordinate and reside outside the plane of the porphyrin macrocycle, thus enabling the simultaneous coordination to meso-tetraphenylporphyrin (TPP) or meso-tetra(4-pyridyl)porphyrin (TPyP) and to the defect site in the Keggin framework. The physical properties of the (TPP)Hf(PW(11)O(39))[TBA](5), (TPyP)Hf(PW(11)O(39))[TBA](5), and (TPP)Zr(PW(11)O(39))[TBA](5) complexes are similar because the metal ions have similar oxidation states, and coordination chemistry.This architecture couples the photonic properties of the porphyrin to the POM because the metal ion is incorporated into both frameworks. Thus the ternary complexes can serve as a basis for the characterization of Hf(IV) and Zr(IV) porphyrins bound to oxide surfaces via the group (IV) metal ions. The Hf(Por) and Zr(Por) bind strongly to TiO(2) nanoparticles and indium tin oxide (ITO) surfaces, but significantly less binds to crystalline SiO(2) or TiO(2) surfaces. Together, the strong binding of the metalloporphyrins to the POM, nanoparticles, and the ITO surfaces, and paucity of binding to crystalline surfaces, suggests that the 3-4 open coordination sites on the Hf(Por) and Zr(Por) are predominantly bound at surface defect sites.

| S-EPMC2883273 | 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