| Recently, more and more attention has been paid on exploring polyoxometalates modified by transition-metal cluster?s?. Due to their special structures, transition-metal cluster?s? may own specific properties, which could affect the polyoxometalate components after being modified by transition-metal clusters. This could attain the goal that might improve the structures and properties of polyoxometalates through coordinating transition-metal cluster?s?.In this paper, we selected polyoxometalates as the basic building units, and different metal ions to obtain novel polyoxometalate-based transition-metal clusters under conventional solution or hydrothermal methods. Moreover, the influence of different synthesis conditions was also discussed, as well as the potential application of these compounds.In this paper, twelve polyoxotungstates modified by transition-metal cluster?s? were obtained through selecting lacunary Dawson or Keggin polyoxometalates as inorganic ligands. Those compounds were characterized through ICP-AES, IR, XPS, XPRD, IP, UV-vis, NMR and so on. The magnetic properties, electrochemical properties and photocatalytic properties of some compounds were primarily studied.1. Two{P8W48}-based compounds modified by transition metals have been synthesized by reaction of the hexavacant Dawson polyoxoanion {P2W12} and copper or molybdenum ions under the conventional aqueous solution.Na12Li16{[Cu?H2O?]2[Cu4?OH?4?H2O?8]2P8W48O184}55H2O ?1?K4Na24Li10{?MoO2?2(P8W48O184)}61H2O ?2?In compound 1, a wheel-type{P8W48} containing two{CU4} clusters and two isolated Cu cations, results in a 10-Cu-containing polyoxotungstate, which represents the first {P8W48}-based compound trapping two transition-metal ?TM? clusters in its inner cavity. Further, the polyoxoanion was connected by Na+ and Li+ cations into a 3D framework. Compound 2 is a 2-Mo-containing{P8W48}-based polyoxotungstate. The two compounds were characterized in solution by UV-vis spectra and electrochemistry. Magnetic study indicates that antiferromagnetic interactions exist in compound 1.2. A polyoxometalate-based inorganic-organic hybrid ionic compound was synthesized by using hexavacant Dawson polyoxoanion{P2W12} under hydrothermal conditions.[WO4{Ni?en?2?H2O?}3] [Ni?en?3]{P2W18O62</sub>}[Ni?en?3]CO3H2O ?3?Compound 3 consists of a heterometallic cluster [WO4{Ni?en?2?H2O?}3]4+, two chiral [Ni?en?3]2+groups, one [CO3]2-group, one water molecule and one Wells-Dawson anion [P2W18O62</sub>]6-, which represents the first POM-based ionic crystal with the heterometallic macrocation cluster. One chiral [Ni?en?3]2+ group could combine with the [P2W18O62</sub>]6- anion by the H-bonding interactions, leading to the whole molecule with the chiral feature of the flack parameter of 0.006?19?. Photocatalytic studies indicate that compound 3 is not only actively photocatalytic for degradation of methylene blue under visible light irradiation, but very stable and easily separated from the reaction system for reuse as well.3. The transition metals play important roles in biological processes, such as their being involved in catalysis, structure, transport, signaling, and sensing. Transition-metal clusters are a unique area within cluster chemistry, and are of interest not only on account of their contribution to the development of modern chemistry but also for their potential use as models for various industrial and biological catalytic processes. Especially, transition-metal cubane clusters represent an important subfamily of cluster chemistry with applications in multidisciplinary fields. Because of their special structures, transition-metal cubane clusters have great potential for magnetism and photocatalysis. This chapter focuses on the synthetic strategies for, structures of, and applications of these polyoxometalate-based transition-metal cubane clusters, particularly highlighting how polyoxometalates can be used as the inorganic ligands to construct cubane-like transition-metal clusters. Although the investigation of polyoxometalate-based cubane-like clusters is still at a nascent stage, it is evident from the examples cited that these materials have a bright future, not only in the field of the synthesis of new polyoxometalate-based transition-metal cubane clusters, but also in the field of the application of old polyoxometalate-based transition-metal cubane clusters. This is because the introduction of POMs imparts excellent and versatile properties to the composite materials, endowing them with both structural integrity and functional tunability. In consideration of the similarity to{Mn4O5Ca} subsite of photosystem ?, this is worth looking forward to making those compounds do photocatalytic oxygen evolution attempts.Twelve new polyoxometalates modified by transition-metal cubane-type clusters were synthesized by choosing lacunary polyoxotungstates as the inorganic ligands, supplementing the library of polyoxometalates modified by transition-metal cubane-type clusters. K10Na3[{Ho?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O31?2]24H2O ?4?K10Na3[{Tm?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O31?2]22H2O ?5? K10Na3 [{Yb?Mn4?{?3-O)2??2-OH?2?H2O??CO3?}??-SiW8O31?2]21H2O ?6?K7Na6[{Sm?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O3,?2]22H2O ?7? K7Na6[{Gd?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O31?2]20H2O ?8?K7Na6[{Er?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O3,?2]22H2O ?9? K7Na5[{Ce?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-SiW8O3,?2]24H2O ?10?K10Na3[{Er?Mn4???3-O?2??2-OH?2?H2O??CO3?}??-GeW8O31?2]23H2O ?11?Na32[{Mn4?OH?3PO4}4?A-a-SiW9O34?4]12H2O ?12?... |
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