Organo-gallium/indium chalcogenide complexes of copper(I): molecular structures and thermal decomposition to ternary semiconductors.

Several organo-gallium/indium chalcogenide complexes of copper(I), stabilized by trialkylphosphines, were isolated, structurally characterized by using single-crystal X-ray diffraction, and investigated in thermolysis experiments. The syntheses with [E(Me3Si)2] (E=S, Se) as a starting material and a chalcogen source involve the elimination of volatile silyl acetate, silyl ethers, and methane from copper(I) acetate, and Group 13 metal trimethyl compounds, respectively. Chalcogenide complexes, according to the general formulas [(R3PCu)4(MeM)4E6] (1-6) and [(R3PCu)6(MeM)4M4S13] (7-9; with R=alkyl and M=Ga, In), and mixed chalcogenide-phenylchalcogenolate complexes [(iPr3PCuEPh)3(MeGaE)4] (10, 11) were isolated. The heavy atom cores of 1-6 consist of an octahedron of chalcogen atoms, interpenetrated by a cube of metal atoms. Depending on the steric demand of the phosphine ligands, two constitutions are observed; the metal atoms of the same element either forming tetrahedra, or parallelograms, respectively. This constitutional isomerism is further investigated by quantum chemical calculations. Complexes 7-9 contain a central sulfur atom, surrounded by two interpenetrating tetrahedra of Group 13 metal atoms, an octahedron of copper atoms, and an icosahedron of twelve outer sulfur atoms; the heavy atom framework of 10 and 11 is a "cut-out" of this structure. Thermolysis experiments include thermogravimetry measurements and subsequent Rietveld phase analysis of the residues by using powder X-ray diffraction. The homologous compounds 1, 3, 4, and 6 yield the respective crystalline ternary semiconductor material CuME2 at temperatures below 300 °C. Partial release of Me3 M during the thermolysis process results in excess copper in the residue and therefore in small amounts of additional binary copper chalcogenide phases or metallic CuM alloys. Compound 8 produces nanocrystalline CuGaS2 at about 300 °C.

Total synthesis and biological activity of the proposed structure of phaeosphaeride A.

The total synthesis of the structure assigned to the natural product phaeosphaeride A 1a was accomplished. The key steps involve the addition of vinyllithium reagent 7 to the acetonide-protected aldehyde 8 to access the carbon backbone of 1a, the introduction of the methoxylamino group followed by intramolecular hetero-Michael cyclization, and methanol elimination to form the dihydropyran ring. In this study, both enantiomers of 1a were synthesized and tested for biological activity. Preliminary results showed that (6R,7R,8R)-1a and (6S,7S,8S)-1a inhibit STAT3-dependent transcriptional activity in a dose-dependent manner and exhibit antiproliferative properties in breast (MDA-MB-231) and pancreatic (PANC-1) cancer cells.

Flexible and hydrophobic Zn-based metal-organic framework.

A zinc-based metal-organic framework Zn(2)(adb)(2)(dabco)·4.5 DMF (K) (DUT-30(Zn), DUT = Dresden University of Technology, adb = 9,10-anthracene dibenzoate, dabco =1,4-diazabicyclo[2.2.2]octane, DMF = N,N-dimethylformamide) was synthesized using a solvothermal route. This MOF exhibits six crystallographic guest dependent phases. Two of them were characterized via single crystal X-ray analysis. The as-synthesized phase K crystallizes in the orthorhombic space group Fmmm, with a = 9.6349(9), b = 26.235(3), and c = 28.821(4) Å and consists of two interpenetrated pillar-layer networks with pcu topology. When the substance loses 0.5 DMF molecules per formula unit, a phase transition from the kinetic phase K to a thermodynamic phase T occurs. Zn(2)(adb)(2)(dabco)·4 DMF (T) crystallizes in the tetragonal space group I4/mmm, with a = 19.5316(8) and c = 9.6779(3) Å. During the evacuation the DUT-30(Zn) undergoes again the structural transformation to A. The activated compound A shows the gate pressure effect in the low pressure region of nitrogen physisorption isotherm and has a BET surface area of 960 m(2 )g(-1) and a specific pore volume of 0.43 cm(3) g(-1). Furthermore, DUT-30(Zn) exhibits a hydrogen storage capacity of 1.12 wt % at 1 bar, a CO(2) uptake of 200 cm(3) g(-1) at -78 °C and 0.9 bar, and a n-butane uptake of 3.0 mmol·g(-1) at 20 °C. The N(2) adsorption process was monitored in situ via X-ray powder diffraction using synchrotron radiation. A low temperature induced transformation of phase A to phase V could be observed if the compound was cooled under vacuum to -196 °C. A further crystalline phase N could be identified if the framework was filled with nitrogen at -196 °C. Additionally, the treatment of activated phase A with water leads to the new phase W.

Trialkylphosphine-stabilized copper(I) phenylchalcogenolate complexes--crystal structures and copper-chalcogenolate bonding.

A series of trialkylphosphine-stabilized copper(I) phenylchalcogenolate complexes [(R(3)P)(m)(CuEPh)(n)] (R = Me, Et, (i)Pr, (t)Bu; E = S, Se, Te) has been prepared and structurally characterized by X-ray diffraction. Structures were found to be mono-, di-, tri-, tetra-, hexa-, hepta-, or decanuclear, depending mainly on size and amount of phosphine ligand. Several structural details were observed, including unusually long Cu-E bonds or secondary Cu-E connections, µ(4)-bridging, and planar bridging chalcogenolate ligands. Relatively rigid Cu-E-C angles were found to be of significant influence on the flexible molecular structures, especially for bridging chalcogenolate ligands, since in these cases a correlation results between the Cu-E-Cu angles and the inclination of the E-C bonds to their Cu-E-Cu planes. We further address some of these phenomena by means of density functional computations.

A highly porous flexible Metal-Organic Framework with corundum topology.

A flexible Metal-Organic Framework Zn(4)O(BenzTB)(3/2) (DUT-13) was obtained by combination of a tetratopic linker and Zn(4)O(6+) as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs.