Dedicated to Professor Francis SØcheresse on the occasion of his 60th birthdayPolygons can be placed on spherical surfaces such that periodical structures of a cyclic nature result, while these can be considered as discrete models for two-dimensional (extended) structures. If we wish to construct a chemical structure on a spherical capsule surface in the same way, we have to remember that 1) pentagons are the basic units for sphere constructions, as is well known, for example, from virus structures, 2) they exist, for example, in the form of { ( [5b]). However, until now it was not possible to synthesize a spherical capsule surface directly by the addition of linkers to the pentagonal units that are available in a dynamic library. [1][2][3][4][5] It is significant that in the Keplerates the linkers describe generic Archimedean solids: in the case of dinuclear linkers M 2 a distorted truncated icosahedron, {M 2 } 30 , and in the case of mononuclear linkers the unique icosidodecahedron (Figure 1) [6] {M 30 }, which has-geometrically speaking-linked M 3 triangles. Surprisingly the related consequences for chemistry have not been discussed until now. In the {M 30 } situation, there is a network of corner-shared triangles on the sphere surface, this can result unique magnetic properties as in the case of the "classical" Keplerate {(Mo VI )Mo . [7, 8] This is the first laboratory example of a "zero-dimensional" system that at low temperatures embodies characteristics of geometrical frustration/magnetic ordering [8b] which otherwise have only been observed in selected one-, two-, and three-dimensional lattice spin systems.[9] Herein we report on the spherical cluster 1 a where the twelve {(Mo VI )Mo VI 5 } type units fix 30 d 1 V IV linkers/centers with spin S = 1/2 in the form of an icosidodecahedron, and thus 1) demonstrating for the first time that the spherical capsule/Keplerate can be directly constructed from the mononuclear linkers and the appropriate molybdate library, [5c] 2) providing the chance to obtain new information regarding the unique molecular magnetism of the {M 30 } type network of linkers/triangles, and 3) clarifying the quantum effects of the spin S = 1/2 vanadyl linkers especially in connection with the two-dimensional S = 1/2 KagomØ lattice which contains linked triangles and exhibits unique magnetic properties.[9a]After adding vanadyl sulfate to an acidified molybdate solution, in the presence of K + ions, compound 1 precipitates after some time in high yield. (A simpler expression for the

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Dedicated to Professor Francis SØcheresse on the occasion of his 60th birthdayPolygons can be placed on spherical surfaces such that periodical structures of a cyclic nature result, while these can be considered as discrete models for two-dimensional (extended) structures. If we wish to construct a chemical structure on a spherical capsule surface in the same way, we have to remember that 1) pentagons are the basic units for sphere constructions, as is well known, for example, from virus structures, 2) they exist, for example, in the form of { ( [5b]). However, until now it was not possible to synthesize a spherical capsule surface directly by the addition of linkers to the pentagonal units that are available in a dynamic library. [1][2][3][4][5] It is significant that in the Keplerates the linkers describe generic Archimedean solids: in the case of dinuclear linkers M 2 a distorted truncated icosahedron, {M 2 } 30 , and in the case of mononuclear linkers the unique icosidodecahedron (Figure 1) [6] {M 30 }, which has-geometrically speaking-linked M 3 triangles. Surprisingly the related consequences for chemistry have not been discussed until now. In the {M 30 } situation, there is a network of corner-shared triangles on the sphere surface, this can result unique magnetic properties as in the case of the "classical" Keplerate {(Mo VI )Mo . [7, 8] This is the first laboratory example of a "zero-dimensional" system that at low temperatures embodies characteristics of geometrical frustration/magnetic ordering [8b] which otherwise have only been observed in selected one-, two-, and three-dimensional lattice spin systems.[9] Herein we report on the spherical cluster 1 a where the twelve {(Mo VI )Mo VI 5 } type units fix 30 d 1 V IV linkers/centers with spin S = 1/2 in the form of an icosidodecahedron, and thus 1) demonstrating for the first time that the spherical capsule/Keplerate can be directly constructed from the mononuclear linkers and the appropriate molybdate library, [5c] 2) providing the chance to obtain new information regarding the unique molecular magnetism of the {M 30 } type network of linkers/triangles, and 3) clarifying the quantum effects of the spin S = 1/2 vanadyl linkers especially in connection with the two-dimensional S = 1/2 KagomØ lattice which contains linked triangles and exhibits unique magnetic properties.[9a]After adding vanadyl sulfate to an acidified molybdate solution, in the presence of K + ions, compound 1 precipitates after some time in high yield. (A simpler expression for the

Two tris(oxouranium)-substituted Keggin and Dawson sandwich-type tungstophosphate heteropolyanions NaI2[(UO)3(H20)6(PW9034)2]21 H20 (1) and Nalsl(UO)3(H20)6(PEW15056)2]'27 H20 (2) have been prepared by reaction of uranium sulphate with [PW9034] 9-and [P2W15056] 12-, respectively, in aqueous media at 4.7 pH. The products were characterized by elemental and thermal analyses, IR, UV-Vis spectroscopy and magnetical susceptibility. The results of these studies suggest that the compounds obtained from Keggin and Dawson trilacunary anions are 2:3 sandwich-type complexes and both exhibit a square antiprismatic stereochemistry for uranium(IV) with retention of polyoxometallate parent structure.

Two polyoxometalates (POMs) with W were synthesized by a two-step, self-assembling method. They were used for stimulation of mesenchymal stem cell differentiation into insulin-producing cells. The nanocompounds (tris(vanadyl)-substituted tungsto-antimonate(III) anions [POM1] and tris-butyltin-21-tungsto-9-antimonate(III) anions [POM2]) were characterized by analytical techniques, including ultraviolet-visible, Fourier transform infrared, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. We found that these polyoxotungstates, with 2-4 nm diameters, did not present toxic effects at the tested concentrations. In vitro, POM1 stimulated differentiation of a greater number of dithizone-positive cells (also organized in clusters) than the second nanocompound (POM2). Based on our in vitro studies, we have concluded that both the POMs tested had significant biological activity acting as active stimuli for differentiation of stem cells into insulin-producing cells. Copyright