Phenyltin-Substituted 9-Tungstogermanate and Comparison with Its Tungstosilicate Analogue

Macrocyclic Inorganic Tin-Containing Oxo Clusters: Heterometallic Strategy for Configuration and Catalytic Activity Modulation

In this work, the first examples of inorganic macrocyclic tin-oxo clusters which are stabilized by sulfate ligands are reported. As determined by X-ray diffraction and photoelectron spectroscopy analyses, the prepared inorganic Sn₁₀ -oxo cluster displays interesting mixed valence behaviors, with 8 Sn⁴⁺ located at the cyclic skeleton and two Sn²⁺ encapsulated in the center. When further introducing Ti⁴⁺ and In³⁺ ions to the synthetic systems, heterometallic Sn₂ Ti₆ and SnIn₅ Ti₆ complexes with Ti₆ (SO₄ )₉ and SnIn₅ (SO₄ )₁₂ macrocyclic skeletons were prepared whose configuration and packing models were affected by the ionic radius of incorporated metals. Moreover, comparative CO₂ reduction experiments confirm that such heterometallic composition can significantly improve the catalytic activities of these inorganic macrocyclic oxo clusters. This work represents a milestone in constructing inorganic tin complexes and also macrocyclic metal oxo clusters with tunable configurations and properties.

Metal-metal bonds in polyoxometalate chemistry

Half a century ago, F. Albert Cotton emphasized the relevance of metal-metal bonding in the constitution of cluster materials. Based on his description, nanoscale polyoxometalates (POMs) normally would not be regarded as cluster materials. One reason is that metal-metal bonding is typically associated with inorganic systems featuring metal centres in low oxidation states, a feature that is not common for POMs. However, over the past decades, there have been increasing reports on POMs integrating different types of metal-metal bonding. This article conceptualises and reviews the area of metal-metal bonded POMs, and their preparation and physicochemical properties. Attention is given to the changes in the electronic structure of POMs, the emergence of covalent dynamics and its impact on the development of applications in catalysis, nanoswitches, donor-acceptor systems, electron storage materials and nanoelectronics (i.e., "POMtronics").

Tailor-made Covalent Organic-Inorganic Polyoxometalate Hybrids: Versatile Platforms for the Elaboration of Functional Molecular Architectures

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.

19-Tungstodiarsenate(III) Functionalized by Organoantimony(III) Groups: Tuning the Structure-Bioactivity Relationship

A family of three discrete organoantimony(III)-functionalized heteropolyanions-[Na{2-(Me2HN(+)CH2)C6H4Sb(III)}As(III)2W19O67(H2O)](10-) (1), [{2-(Me2HN(+)CH2)C6H4Sb(III)}2As(III)2W19O67(H2O)](8-) (2), and [{2-(Me2HN(+)CH2)C6H4Sb(III)}{WO2(H2O)}{WO(H2O)}2(B-β-As(III)W8O30)(B-α-As(III)W9O33)2](14-) (3)-have been prepared by one-pot reactions of the 19-tungstodiarsenate(III) precursor [As(III)2W19O67(H2O)](14-) with 2-(Me2NCH2)C6H4SbCl2. The three novel polyanions crystallized as the hydrated mixed-alkali salts Cs3KNa6[Na{2-(Me2HN(+)CH2)C6H4Sb(III)}As(III)2W19O67(H2O)]·43H2O (CsKNa-1), Rb2.5K5.5[{2-(Me2HN(+)CH2)C6H4Sb(III)}2As(III)2W19O67(H2O)]·18H2O·Me2NCH2C6H5 (RbK-2), and Rb2.5K11.5[{2-(Me2HN(+)CH2)C6H4Sb(III)}{WO2(H2O)}{WO(H2O)}2(B-β-As(III)W8O30)(B-α-As(III)W9O33)2]·52H2O (RbK-3), respectively. The number of incorporated {2-(Me2HN(+)CH2)C6H4Sb(III)} units could be tuned by careful control of the experimental parameters. Polyanions 1 and 2 possess a dimeric sandwich-type topology, whereas 3 features a trimeric, wheel-shaped structure, representing the largest organoantimony-containing polyanion. All three compounds were fully characterized in the solid state via single-crystal X-ray diffraction (XRD), infrared (IR) spectroscopy, and thermogravimetric analysis, and their aqueous solution stability was validated by ultraviolet-visible light (UV-vis) and multinuclear ((1)H, (13)C, and (183)W) nuclear magnetic resonance (NMR) spectroscopy. Effective inhibition against six different types of bacteria was observed for 1 and 2, and we could extract a structure-bioactivity relationship for these polyanions.

Organoantimony(III)-Containing Tungstoarsenates(III): From Controlled Assembly to Biological Activity

A family of three sandwich-type, phenylantimony(III)-containing tungstoarsenates(III), [(PhSb(III) ){Na(H2 O)}As(III) 2 W19 O67 (H2 O)](11-) (1), [(PhSb(III) )2 As(III) 2 W19 O67 (H2 O)](10-) (2), and [(PhSb(III) )3 (B-α-As(III) W9 O33 )2 ](12-) (3), have been synthesized by one-pot procedures and isolated as hydrated alkali metal salts, Cs3 K3.5 Na4.5 [(PhSb(III) ){Na(H2 O)}As(III) 2 W19 O67 (H2 O)]⋅41H2 O (CsKNa-1), Cs4.5 K5.5 [(PhSb(III) )2 As(III) 2 W19 O67 (H2 O)]⋅35H2 O (CsK-2), and Cs4.5 Na7.5 [(PhSb(III) )3 (B-α-As(III) W9 O33 )2 ]⋅42H2 O (CsNa-3). The number of incorporated {PhSb(III) } units could be selectively tuned from one to three by careful control of the reaction parameters. The three compounds were characterized in the solid state by single-crystal XRD, IR spectroscopy, and thermogravimetric analysis. The aqueous solution stability of sandwich polyanions 1-3 was also studied by multinuclear ((1) H, (13) C, (183) W) NMR spectroscopy. Effective inhibitory activity against six different kinds of bacteria was identified for all three polyanions, for which the activity increased with the number of incorporated {PhSb(III) } groups.

Two Keggin sandwich-type tungstophosphates modified by open-chain carboxyethyltin groups and transition metals

Two new crystalline Keggin sandwich-type POMs containing open-chain carboxyethyltin groups showed good fluorescence quenching effects and oxidation catalytic activities.

Synthesis and characterization of multinuclear manganese-containing tungstosilicates

The five manganese-containing, Keggin-based tungstosilicates [Mn(II)3(OH)3(H2O)3(A-α-SiW9O34)](7-) (1), [Mn(III)3(OH)3(H2O)3(A-α-SiW9O34)](4-) (2), [Mn(III)3(OH)3(H2O)3(A-β-SiW9O34)](4-) (3), [Mn(III)3Mn(IV)O3(CH3COO)3(A-α-SiW9O34)](6-) (4), and [Mn(III)3Mn(IV)O3(CH3COO)3(A-β-SiW9O34)](6-) (5) were synthesized in aqueous medium by interaction of [A-α-SiW9O34](10-) or [A-β-SiW9O34H](9-) with either MnCl2 (1) or [Mn(III)8Mn(IV)4O12(CH3COO)16(H2O)4] (2-5) under carefully adjusted reaction conditions. The obtained salts of these polyanions were analyzed in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric analysis. The salts of polyanions 1, 2, and 4 were further characterized in the solid state by magnetic studies, as well as in solution by electrochemistry.

Synthesis and biological activity of organoantimony(III)-containing heteropolytungstates

Three discrete organoantimony(III)-containing heteropolytungstates [(PhSb(III))(4)(A-α-Ge(IV)W(9)O(34))(2)](12-) (1), [(PhSb(III))(4)(A-α-P(V)W(9)O(34))(2)](10-) (2), and [{2-(Me(2)NCH(2)C(6)H(4))Sb(III)}(3)(B-α-As(III)W(9)O(33))](3-) (3) have been synthesized in one-pot reactions in aqueous medium using the appropriate lacunary heteropolyanion precursor and organoantimony(III) source. Polyanions 1-3 were isolated as hydrated salts, (NH(4))(12)[(PhSb(III))(4)(A-α-Ge(IV)W(9)O(34))(2)]·20H(2)O (1a), Rb(9)Na[(PhSb(III))(4)(A-α-P(V)W(9)O(34))(2)]·20H(2)O (2a), and Rb(3)[{2-(Me(2)NCH(2)C(6)H(4))Sb(III)}(3)(B-α-As(III)W(9)O(33))]·7H(2)O (3a). The compounds 1a-3a were fully characterized in the solid state using infrared (IR) spectroscopy, single-crystal XRD, and thermogravimetric and elemental analyses. The stability of 1-3 in aqueous solution was confirmed by multinuclear NMR ((1)H, (13)C, (31)P, and (183)W) spectroscopy. Preliminary studies on the biological activity of 1-3 showed that all three compounds might act as potent antimicrobial agents.