Stefanie Dehnen

Li10SnP2S12: an affordable lithium superionic conductor.

The reaction of Li2S and P2S5 with Li4[SnS4], a recently discovered, good Li(+) ion conductor, yields Li10SnP2S12, the thiostannate analogue of the record holder Li10GeP2S12 and the second compound of this class of superionic conductors with very high values of 7 mS/cm for the grain conductivity and 4 mS/cm for the total conductivity at 27 °C. The replacement of Ge by Sn should reduce the raw material cost by a factor of ~3.

Chalcogen-Bridged Copper Clusters

The investigation of coinage metal molecular clusters bridged by chalcogen atoms represents an area of ever increasing activity in recent chemical and material science research. This is largely due to the relatively high ionic and even higher electric conductivity of binary coinage metal chalcogenides, which leads to properties intermediate between those of semiconducting and metallic phases. In addition, the size-dependency of the chemical, physical, and structural properties of substances on going from small molecules to bulk materials is of general interest. Approaches towards the synthesis and investigation of such clusters have included the study of colloidal nanoparticles with a narrow size distribution, as well as the formation and isolation of crystalline cluster compounds amenable to structural determination by single-crystal X-ray diffraction analysis. Irrespective of the chosen synthesis route, the molecules have to be kinetically protected from decomposition to the thermodynamically favored binary phases by a suitable ligand sphere, often consisting of tertiary phosphane molecules, or a combination of phosphanes and organic groups. In this report, we concentrate on the syntheses and structural as well as physical properties of ligand-stabilized, chalcogen-bridged copper clusters, which have been comprehensively studied by means of experimental and quantum chemical investigations.

Formation of a Strandlike Polycatenane of Icosahedral Cages for Reversible One-Dimensional Encapsulation of Guests

Self-assembly of ZnCl(2) and the ligand 2,4,6-tris(4-pyridyl)pyridine (pytpy) in solution yields [(ZnCl(2))(12)(pytpy)(8)](n)·xCHCl(3), a polycatenane consisting of a strand of mechanically interlocking icosahedral cages with an inner volume of more than 2700 Å(3). This can be used to encapsulate guest molecules of appropriate size and polarity, forming a precisely defined three-dimensional array of solvent nanodroplets within the crystalline framework. The dynamic composition of these droplets was studied using quantitative solid-state NMR spectroscopy.

[BMIm]4[Sn9Se20]: Ionothermal Synthesis of a Selenidostannate with a 3D Open-Framework Structure

The reaction of [K(4)(H(2)O)(4)][SnSe(4)] with [BMIm][BF(4)] at 130-180 °C afforded [BMIm](4)[Sn(9)Se(20)] (1). The anion of the title compound represents a unique three-dimensional (3D) open framework, based on a variety of interconnectivity modes of Sn/Se units that lead to a system of six intersecting channels. 1 comprises the first example of a binary 3D open-framework selenidostannate anion and the first 3D open-framework chalcogenido metalate to be conveniently obtained by ionothermal synthesis.

[Pd3Sn8Bi6]4-: a 14-vertex Sn/Bi cluster embedding a Pd3 triangle.

The endohedral cluster anion [Pd(3)Sn(8)Bi(6)](4-) crystallizes as its K([2.2.2]crypt)(+) salt 1 upon reaction of [K([2.2.2]crypt)](2)[Sn(2)Bi(2)]·en and Pd(dppe)(2) in 1,2-diaminoethane (en)/toluene and incorporates a complete Pd(3) triangular cluster within a medium-size 14-vertex cage of Sn and Bi atoms. 1 was characterized by a combination of single crystal diffraction, ESI mass spectrometry, elemental analysis, and magnetic measurements. According to quantum chemical investigations, the Pd(3) triangle interacts only weakly with the Sn/Bi cluster shell despite the relatively small cavity inside the cage.

Synthesis and reactivity of functionalized binary and ternary thiometallate complexes [(RT)4S6], [(RSn)3S4]2-, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4- (R=C2H4COOH, CMe2CH2COMe; T=Ge, Sn).

A series of compounds comprising functionalized thiometallate cages [(RT)4S6] (R terminated by COO(H) or COR groups), based on adamantane (T=Ge) or double-decker (T=Sn) type structures or [(RSn)3S4]2- anionic defect heterocubanes were synthesized and their reactions with 1) transition-metal compounds and 2) hydrazine derivatives were explored. Hence it was possible to generate functionalized ternary CuSnS or CuGeS clusters and to transfer COR ligands into CR(N-NH2) or CR(N-NHPh) terminal groups, respectively. The report provides the proof-of-principle for a directed functionalization and derivatization of chalcogenidometallate cages with respect to the formation of chalcogenidometallate-organic hybrid compounds containing M/E semiconductor nodes, as an alternative to the so far most prominent M/O combination in metal-organic frameworks. DFT investigations deliver further insight in the peculiarities of Ge/S versus Sn/S precursors and their products.

Doped Semimetal Clusters: Ternary, Intermetalloid Anions [Ln@Sn7Bi7]4– and [Ln@Sn4Bi9]4– (Ln = La, Ce) with Adjustable Magnetic Properties

Two K([2.2.2]crypt) salts of lanthanide-doped semimetal clusters were prepared, both of which contain at the same time two types of ternary intermetalloid anions, [Ln@Sn(7)Bi(7)](4-) and [Ln@Sn(4)Bi(9)](4-), in 0.70:0.30 (Ln = La) or 0.39:0.61 (Ln = Ce) ratios. The cluster shells represent nondeltahedral, fullerane-type arrangements of 14 or 13 main group metal atoms that embed the Ln(3+) cations. The assignment of formal +III oxidation states for the Ln sites was confirmed by means of magnetic measurements that reveal a diamagnetic La(III) compound and a paramagnetic Ce(III) analogue. Whereas the cluster anions with a 14-atomic main-group metal cage represent the second examples in addition to a related Eu(II) cluster published just recently, the 13-atomic cages exhibit a yet unprecedented enneahedral topology. In contrast to the larger cages, which accord to the Zintl-Klemm-Busmann electron number-structure correlation, the smaller clusters require a more profound interpretation of the bonding situation. Quantum chemical investigations served to shed light on these unusual complexes and showed significant narrowing of the HOMO-LUMO gap upon incorporation of Ce(3+) within the semimetal cages.

[Eu@Sn6Bi8]4−: A Mini‐Fullerane‐Type Zintl Anion Containing a Lanthanide Ion

Experimental and theoretical studies on intermetalloid cluster anions, that is, main-group-element cages with interstitial transition metal atom(s), have attracted the interest of chemists and physicists for about a decade. This is due to a large variety of novel structural types, unprecedented bonding situations, and unexpected chemical and physical properties of the resulting phases; furthermore, the compounds are discussed as being models for doped materials and/or precursors to novel intermetallic phases. The structures of the known intermetalloid anions are controlled by both the synthetic reaction route and the embedded transition metal atom. For instance, whereas most of the reports include closed-shell d metal atoms, two of the most recent results showed that endohedral Group 8 or Group 9 metal atoms serve to stabilize small non-deltahedral clusters [Fe@Ge10] 3 [3] and [Co@Ge10] 3 , that would not exist without interstitial atom. These anions feature exclusively nondeltahedra faces and thus direct toward fullerene-like molecular structures. To date, it has not been possible to isolate main-groupmetal cages stabilized by Ln ions, although these elements are well-known as both components of intermetallic phases, for example, in EuSn3Sb4, [5] and as guests in doped main-groupelement host lattices, for example in nanocrystalline LED phosphors such as M2Si5N8:Eu 2+ (M = Sr, Ba) or laser materials such as Nd:YAG. Moreover, photoelectron spectroscopy and quantum chemical investigations indicated the existence of [LnSin] species (3 n 13; Ln = Ho, Gd, Pr, Sm, Eu, Yb), [EuSin] (3 n 17), and Yb@Pb12 in the gas phase. In the condensed phase, Ln ions have only been trapped by carbon cages such as M@C82 and M2@Cx (M = La– Nd, Sm–Lu; x = 72, 78, 80). These clusters have been discussed as “designer” materials because a small variation in their composition can significantly manipulate their chemical, electronic, and magnetic properties. For instance, the magnetic moment is tunable by the type and oxidation state of the incorporated lanthanide ion. We have extended our recent investigations of compounds comprising ternary Zintl anions, such as [K([2.2.2]crypt)]4[Zn@Zn5Sn3Bi3@Bi5]·0.5en·0.5tol (en = 1,2ethylenediamine, tol = toluene), formed upon reactions of the binary precursor [Sn2Bi2] 2 [12] by the introduction of a lanthanide ion, which gave rise for the formation of a spherical cluster with a fullerene-related structure: The reaction of [K([2.2.2]crypt)]2[Sn2Bi2]·en with [(C5Me4H)3Eu] yields the desired compound [K([2.2.2]crypt)]4[Eu@Sn6Bi8]·1.1en (1) as extremely air-sensitive, dark brown crystals (yield: 11% with respect to [Sn2Bi2] 2 ) along with the crystalline starting material (>80 %; see the Supporting Information). Six Sn and eight Bi atoms in the [Eu@Sn6Bi8] 4 anion in 1 (Figure 1) form a polyhedron that consists of nine nondeltahedral faces, namely six pentagons and three square faces. This enneahedron has been unknown to date in an isolated, ligand-free form. However, topologically identical polyhedra were previously observed and discussed as part of complicated networks within two solid-state phases: elongated in the intermetallic phase Ag7Te4 [13] or undistorted in

Directed Formation of an Organotin Sulfide Cavitand and Its Transformation into a Rugby-Ball-like Capsule

We report the systematic synthesis and thorough characterization of a discrete organotin sulfide cavitand, [R(B)(4)Sn(12)S(20)] {1, R(B) = 1,5-bis[(E)-2-(4-methylpentan-2-ylidene)hydrazinyl]naphthalene}, which readily undergoes a unique transformation into a stable, rugby-ball-like capsule, [R(B)(3)Sn(6)S(8)][(SnCl(3))(2)] (2), upon addition of a protic acid. DMF molecules are embedded within the cavities of both compounds by hydrogen-bonding interactions, spotlighting the title compounds with respect to molecular containment.

Thiostannate Tin–Tin Bond Formation in Solution: In Situ Generation of the Mixed-Valent, Functionalized Complex [{(RSnIV)2(μ-S)2}3SnIII2S6]†

In broad daylight: The double-decker thiostannate [(RSn(IV))(4)S(6)] (1, R = CMe(2)CH(2)COMe) condenses to form [{(RSn(IV))(2)(mu-S)(2)}(3)Sn(III)(2)S(6)] (2; see picture). This mixed-valent complex, which formally contains both Sn(III) and Sn(IV) atoms as confirmed by Mössbauer spectroscopy and DFT calculations, forms by a complicated, concerted mechanism. Additionally, 2 provides six carbonyl groups for further derivatization.