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Visible‐Light Sensitization and Photoenergy Storage in Quantum Dot/Polyoxometalate Systems
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Prof. Tetsuya Kida Hiromasa Furuso Kota Kumamoto Azzah Dyah Pramata Prof. Masayoshi Yuasa Prof. Kengo Shimanoe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7462-7469
Recently, the process by which energy is transferred from photoexcited semiconductor nanocrystals, called quantum dots (QDs), to other semiconductors has attracted much attention and has potential application in solar energy conversion (i.e., QD‐sensitized solar cells). Sensitization of wide band gap polyoxometalates (POMs) to visible light by using CuInS2 QDs dispersed in an organic solution is demonstrated herein. Photoluminescence quenching and lifetime studies revealed efficient electron transfer from the CuInS2 QDs to POMs, such as SiW12O40 and W10O32, that were hybridized with a cationic surfactant. CuInS2 QDs function as an antenna that absorbs visible light and supplies electrons to the POMs to enable certain photocatalytic reactions, including noble‐metal‐ion reduction. The photoenergy storage capabilities of the QD‐POM system, in which electrons photogenerated in QDs by visible‐light excitation are trapped and accommodated by POMs to form reduced POM, are also demonstrated. Electrons stored in the POM can be later discharged through reductive reactions, such as oxygen reduction, in the dark. 相似文献
3.
Archismita Misra Karoly Kozma Carsten Streb May Nyman 《Angewandte Chemie (International ed. in English)》2020,59(2):596-612
Polyoxometalates (POMs) are molecular metal‐oxide anions applied in energy conversion and storage, manipulation of biomolecules, catalysis, as well as materials design and assembly. Although often overlooked, the interplay of intrinsically anionic POMs with organic and inorganic cations is crucial to control POM self‐assembly, stabilization, solubility, and function. Beyond simple alkali metals and ammonium, chemically diverse cations including dendrimers, polyvalent metals, metal complexes, amphiphiles, and alkaloids allow tailoring properties for known applications, and those yet to be discovered. This review provides an overview of fundamental POM–cation interactions in solution, the resulting solid‐state compounds, and behavior and properties that emerge from these POM–cation interactions. We will explore how application‐inspired research has exploited cation‐controlled design to discover new POM materials, which in turn has led to the quest for fundamental understanding of POM–cation interactions. 相似文献
4.
Aleksandar Bijelic Manuel Aureliano Annette Rompel 《Angewandte Chemie (International ed. in English)》2019,58(10):2980-2999
Polyoxometalates (POMs) are an emerging class of inorganic metal oxides, which over the last decades demonstrated promising biological activities by the virtue of their great diversity in structures and properties. They possess high potential for the inhibition of various tumor types; however, their unspecific interactions with biomolecules and toxicity impede their clinical usage. The current focus of the field of biologically active POMs lies on organically functionalized and POM‐based nanocomposite structures as these hybrids show enhanced anticancer activity and significantly reduced toxicity towards normal cells in comparison to unmodified POMs. Although the antitumor activity of POMs is well documented, their mechanisms of action are still not well understood. In this Review, an overview is given of the cytotoxic effects of POMs with a special focus on POM‐based hybrid and nanocomposite structures. Furthermore, we aim to provide proposed mode of actions and to identify molecular targets. POMs are expected to develop into the next generation of anticancer drugs that selectively target cancer cells while sparing healthy cells. 相似文献
5.
Quan Sha Dongwei Cao Jiaxin Wang Hanbin Hu Jiaxin Li Wei Chen Lei He Graham N. Newton Prof. Dr. Yu-Fei Song 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(57):e202201899
The host–guest interaction can remarkably alter the physiochemical properties of composite materials. It is crucial to clarify the mechanism by revealing the influence of the host on the electronic structure of the guest molecules. Herein, we study the structural variation of polyoxometalates (POMs) after being confined in single-walled carbon nanotubes (SWNT). What we found is that in addition to the reported charge transfer from SWNT to POM, an intramolecular electron transfer within a single POM cluster can be observed in the POM@SWNT composites. Moreover, the charge density on the bridged oxygen of POMs is prominently enhanced. The structural change and electron reconfiguration of POMs upon encapsulation in SWNT significantly speed up electron and ion transport, leading to the improved electrochemical performance for sodium ions storage. 相似文献
6.
Surfactant‐Dependent Charge Transfer between Polyoxometalates and Single‐Walled Carbon Nanotubes: A Fluorescence Spectroscopic Study
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Dr. Liu Hong Prof. Naotoshi Nakashima Dr. Yunxing Li Prof. Hongbing Jia Prof. Cheng Yang 《化学:亚洲杂志》2018,13(2):210-216
Hybridizations of redox‐active polyoxometalates (POMs) with single‐walled carbon nanotubes (SWNTs) have been widely investigated for their diverse applications. For the purpose of constructing high‐quality electronic devices, controlling charge transfer within POM/SWNT hybrids is an inevitable issue. As determined by means of fluorescence spectroscopy, electron transfer between SWNTs and a common POM dopant, phosphomolybdic acid (PMo12), can be tuned simply by an alteration of nanotube surfactant type from anionic to nonionic. The mechanism is attributed to the influence of surfactant type on the stabilization of the electron donor–acceptor hybrid and effect of surfactant–nanotube interactions. These results will be important to control charge‐transport behavior in nanohybrids consisting of carbon nanotubes. 相似文献
7.
Amphiphilic Polyoxometalates for the Controlled Synthesis of Hybrid Polystyrene Particles with Surface Reactivity
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Dr. Jennifer Lesage de La Haye Dr. Jean‐Michel Guigner Dr. Eric Marceau Prof. Laurent Ruhlmann Prof. Bernold Hasenknopf Dr. Emmanuel Lacôte Dr. Jutta Rieger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2948-2953
Amphiphilic organo‐polyoxometalates (POMs) used in the radical emulsion polymerization of styrene allowed the preparation in aqueous medium of stable 50–100 nm polystyrene–POM composite latexes. Thanks to the presence of a trithiocarbonate group in the POM amphiphile, POMs could be covalently linked to the polymer particle surface. The chemical and catalytic integrity of the POMs was confirmed, and the POM‐mediated surface photoactivity of the latexes was demonstrated by the spatially controlled nucleation of silver nanoparticles at the periphery of the composites. 相似文献
8.
Yu‐Fei Song De‐Liang Long Chris Ritchie Leroy Cronin 《Chemical record (New York, N.Y.)》2011,11(3):158-171
The latest advances in the area of polyoxometalate (POM)‐based inorganic/organic hybrid materials prepared by self‐assembly, covalent modification, and supramolecular interactions are presented. This Review is composed of five sections and documents the effect of organic cations on the formation of novel POMs, surfactant encapsulated POM‐based hybrids, polymeric POM/organic hybrid materials, POMs‐containing ionic crystals, and covalently functionalized POMs. In addition to their role in the charge‐balancing, of anionic POMs, the crucial role of organic cations in the formation and functionalization of POM‐based hybrid materials is discussed. DOI 10.1002/tcr.201100002 相似文献
9.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(10):2708-2713
A series of polyoxometalates (POMs) that incorporate the highest‐nuclearity Ln clusters that have been observed in such structures to date (Ln26 , Ln=La and Ce) are described, which exhibit giant multishell configurations (Ln⊂W6⊂Ln26⊂W100). Their structures are remarkably different from known giant POMs that feature multiple Ln ions. In particular, the incorporated Ln–O clusters with a nuclearity of 26 are significantly larger than known high‐nuclearity (≤10) Ln–O clusters in POM chemistry. Furthermore, they also contain the largest number of La and Ce centers for any POM reported to date and represent a new kind of rare giant POMs with more than 100 W atoms. Interestingly, the La26‐containing POM can undergo a single‐crystal to single‐crystal structural transformation in the presence of various transition‐metal ions, such as Cu2+, Co2+, and Ni2+, from an inorganic molecular nanocluster into an inorganic–organic hybrid extended framework that is built from POM building blocks with even higher‐nuclearity La28 clusters bridged by transition‐metal complexes. 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(11):3020-3024
Anionic Keggin polyoxometalates (POMs) and ether linkage‐enriched ammonium ions spontaneously self‐assemble into rectangular ultrathin nanosheets in aqueous media. The structural flexibility of the cation is essential to form oriented nanosheets; as demonstrated by single‐crystal X‐ray diffraction measurements. The difference in initial conditions exerts significant influence on selecting for self‐assembly pathways in the energy landscape. Photoillumination of the POM sheets in pure water causes dissolution of reduced POMs, which allowed site‐specific etching of nanosheets using laser scanning microscopy. By contrast, photoetching was suppressed in aqueous AgNO3 and site‐selective deposition of silver nanoparticles occurred as a consequence of electron transfer from the photoreduced POMs to Ag+ ions on the nanosheet surface. 相似文献
11.
Tailor–made Covalent Organic‐Inorganic Polyoxometalate Hybrids: Versatile Platforms for the Elaboration of Functional Molecular Architectures
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Dr. Guillaume Izzet Dr. Florence Volatron Prof. Dr. Anna Proust 《Chemical record (New York, N.Y.)》2017,17(2):250-266
Post‐functionalization of organically modified polyoxometalates (POMs) is a powerful synthetic tool to devise functional building blocks for the rational elaboration of POM‐based molecular materials. In this personal account we focus on iodoaryl‐terminated POM platforms, describe reliable routes to the synthesis of covalent organic‐inorganic POM‐based hybrids and their integration into advanced molecular architectures or multi‐scale assemblies as well as their immobilization onto surfaces. Valorisation of the remarkable redox properties of POMs in the fields of artificial synthesis and molecular electronic is especially considered. 相似文献
12.
Zhang G Keita B Brochon JC de Oliveira P Nadjo L Craescu CT Miron S 《The journal of physical chemistry. B》2007,111(7):1809-1814
As a step toward the elucidation of the mechanistic pathways governing the known bioactivity of polyoxometalates (POMs), two representative molecules of this class of chemicals, the wheel-shaped [NaP(5)W(30)O(110)]14- (P(5)W(30)) and the Keggin-type anion [H(2)W(12)O(40)]6- (H(2)W(12)), are shown, by two independent techniques, to interact with the fatty-acid-free human serum albumin (HSA). The excited-state lifetime of the single tryptophan molecule of this protein is dramatically decreased by the binding. The quenching mechanism is found to constitute the first example of energy transfer between HSA and POMs. Such molecular recognition is believed to be a key step for subsequent evolution of the systems. Circular dichroism (CD) was used to assess the structural effects of POM binding on HSA and to confirm the interaction revealed by fluorescence studies. CD experiments showed that the two POMs have different effects on the secondary structure of the protein. Binding P(5)W(30) partially unfolds the protein whereas H(2)W(12) has no remarkable effect on the structure of the protein. 相似文献
13.
In this minireview, we discuss the recent efforts on expanding the catalytic capabilities of polyoxometalates (POM) through emulsion catalysis approaches with novel catalytic-active POM–organic hybrid clusters as emulsifiers. The hybrid emulsifiers include surfactant encapsulated POM complexes, molecular POMs–organic hybrids, and POM-based solid nanoparticles. With such novel approaches the catalytic efficiency of the POMs can be significantly improved by enhancing the compatibility of the POMs with organic media, providing catalytic interface for biphasic reactions, as well as easier preparation, and better recyclability. Particularly, a simple, green chemistry method to prepare metal nanoparticle materials with POMs as both reducing and capping agents in aqueous is reviewed. 相似文献
14.
Incorporating Polyoxometalates into a Porous MOF Greatly Improves Its Selective Adsorption of Cationic Dyes
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Ai‐Xue Yan Dr. Shuang Yao Prof. Yang‐Guang Li Dr. Zhi‐Ming Zhang Dr. Ying Lu Dr. Wei‐Lin Chen Prof. En‐Bo Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):6927-6933
Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL‐101 resulting in a series of POM–MOF composite materials POM@MIL‐101 (POM=K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one‐pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr3+ ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy‐dispersive X‐ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL‐101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL‐101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL‐101. An uptake capacity of 371 mg g?1, comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL‐101 in the methylene blue (MB) solution (100 mL of 100 mg L?1 MB solution). Further study revealed that the POM@MIL‐101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL‐101 (10 mg) towards MB (100 mL of 10 mg L?1) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL‐101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process. 相似文献
15.
Polyoxometalate‐Mediated One‐Pot Synthesis of Pd Nanocrystals with Controlled Morphologies for Efficient Chemical and Electrochemical Catalysis
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Dr. Dongheun Kim Ji Hyun Seog Minjune Kim MinHo Yang Eleanor Gillette Prof. Dr. Sang Bok Lee Prof. Dr. Sang Woo Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5387-5394
Polyoxometalates (POMs), as inorganic ligands, can endow metal nanocrystals (NCs) with unique reactivities on account of their characteristic redox properties. In the present work, we present a facile POM‐mediated one‐pot aqueous synthesis method for the production of single‐crystalline Pd NCs with controlled shapes and sizes. The POMs could function as both reducing and stabilizing agents in the formation of NCs, and thus gave a fine control over the nucleation and growth kinetics of NCs. The prepared POM‐stabilized Pd NCs exhibited excellent catalytic activity and stability for electrocatalytic (formic acid oxidation) and catalytic (Suzuki coupling) reactions compared to Pd NCs prepared without the POMs. This shows that the POMs play a pivotal role in determining the catalytic performance, as well as the growth, of NCs. We envision that the present approach can offer a convenient way to develop efficient NC‐based catalyst systems. 相似文献
16.
Corentin Rinfray Dr. Guillaume Izzet Prof. Dr. Jean Pinson Dr. Sarra Gam Derouich Dr. Jean‐Jacques Ganem Dr. Catherine Combellas Dr. Frédéric Kanoufi Prof. Dr. Anna Proust 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13838-13846
Polyoxometalates (POMs) are attractive candidates for the rational design of multi‐level charge‐storage materials because they display reversible multi‐step reduction processes in a narrow range of potentials. The functionalization of POMs allows for their integration in hybrid complementary metal oxide semiconductor (CMOS)/molecular devices, provided that fine control of their immobilisation on various substrates can be achieved. Owing to the wide applicability of the diazonium route to surface modification, a functionalized Keggin‐type POM [PW11O39{Ge(p‐C6H4‐C?C‐C6H4‐${{\rm N}{{+\hfill \atop 2\hfill}}}$ )}]3? bearing a pending diazonium group was prepared and subsequently covalently anchored onto a glassy carbon electrode. Electron transfer with the immobilised POM was thoroughly investigated and compared to that of the free POM in solution. 相似文献
17.
The Two‐Step Assemblies of Basic‐Amino‐Acid‐Rich Peptide with a Highly Charged Polyoxometalate
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Teng Zhang Dr. Hong‐Wei Li Prof. Dr. Yuqing Wu Dr. Yizhan Wang Prof. Dr. Lixin Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9028-9033
Two‐step assembly of a peptide from HPV16 L1 with a highly charged europium‐substituted polyoxometalate (POM) cluster, accompanying a great luminescence enhancement of the inorganic polyanions, is reported. The mechanism is discussed in detail by analyzing the thermodynamic parameters from isothermal titration calorimetry (ITC), time‐resolved fluorescent and NMR spectra. By comparing the actions of the peptide analogues, a binding process and model are proposed accordingly. The driving forces in each binding step are clarified, and the initial POM aggregation, basic‐sequence and hydrophobic C termini of peptide are revealed to contribute essentially to the two‐step assembly. The present study demonstrates both a meaningful preparation for bioinorganic materials and a strategy using POMs to modulate the assembly of peptides and even proteins, which could be extended to other proteins and/or viruses by using peptides and POMs with similar properties. 相似文献
18.
Roy S Bossers LC Meeldijk HJ Kuipers BW Kegel WK 《Langmuir : the ACS journal of surfaces and colloids》2008,24(3):666-669
Polyoxometalates or POMs, a class of inorganic transition metal-oxide based clusters, have gained significant interest owing to their catalytic, magnetic, and material science applications. All such applications require high surface area POM based materials. However, chemically synthesized POMs are still at most in the range of a few nanometers, with their size and morphology being difficult to control. Hence, there is an immediate need to develop design principles that allow easy control of POM morphology and size on mesoscopic (50-500 nm) length scales. Here, we report a design strategy to meet this need. Our method reported here avoids a complex chemical labyrinth by using a prefabricated cationic 1,2-dioleol-3-trimethylammonium-propane (DOTAP) vesicle as a scaffold/structure directing agent and gluing simple anionic heptamolybdates by electrostatic interaction and hydrogen bonds to form large POM spheres. By this method, complexity in the resulting structure can be deliberately induced either via the scaffold or via the oxometalate. The high degree of control in the matter of the size and morphology of the resulting POM superstructures renders this method attractive from a synthetic standpoint. 相似文献
19.
Hailong Yang Guoli Yue Tao Li Lingling Du Prof. Haohong Li Prof. Zhirong Chen Prof. Shoutian Zheng 《欧洲无机化学杂志》2023,26(32):e202300264
The coming big-data era has created a huge demand for next-generation memory technologies with characters of higher data-storage densities, faster access speeds, lower power consumption and better environmental compatibility. In this field, the design of resistive switching active materials is pivotal but challengeable. Polyoxometalates (POMs) are promising candidates for next-generation molecular memristors due to their versatile redox characters, excellent electron reservoirs and good compatibility/convenience in microelectronics processing. In this review, five kinds of POM-based active materials in nonvolatile memories (inorganic POMs, crystalline organic-inorganic hybrid POMOFs, polymer modified POMs, POM/transition metal oxides composites and the deposition of POM on metal surfaces) were described. The components of POMs active materials, device fabrications, device parameters, and resistive switching mechanisms relative to their structures were summarized. Finally, challenges and future perspectives of POMs-based memristors were also presented. 相似文献
20.
Dr. Jutta Rieger Dr. Tarek Antoun Soo‐Hyon Lee Marion Chenal Gaëlle Pembouong Jennifer Lesage de la Haye Iban Azcarate Prof. Bernold Hasenknopf Dr. Emmanuel Lacôte 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(11):3355-3361
We report the synthesis of the first organo‐POM with thermoresponsive properties. Our concept will provide chemists with a new tool to design POMs whose solubility is reversibly controllable through an external stimulus. POM–polymer TBA7[POM]‐poly(N,N‐diethylacrylamide) (POM–PDEAAm), was prepared by grafting PDEAAm‐NH2 (obtained by RAFT polymerization) onto the activated Dawson acyl‐POM, α2‐[P2W17O61SnCH2CH2C(?O)]6?. Extensive MS analysis was used to monitor the chain‐functionalization steps and to confirm the formation of the hybrid. Aqueous solutions of the (NH4)7[POM–PDEAAm] exhibited a LCST of 38 °C. Thus, the solubility/aggregation of the hybrid was reversibly controlled by changing the temperature. Above 38 °C, the solution became cloudy, and cleared again upon cooling. Dynamic light scattering (DLS) revealed the formation of small aggregates in the range 100 nm. We assumed that the charged POM head units prevented the formation of the larger‐scattering aggregates that are usually observed for PDEAAm, and promoted the formation of micelle‐like structures. The conjugate exhibited a temperature transition, which was different from that of the polymer and depended on the counterions associated with the POM. This result demonstrates the potential for merging organic (in this case, polymer) and inorganic structures to afford materials that exhibit new properties. 相似文献