Symmetry breaking of α-[H2W12O40](6-) depends on the transformation of isopolyoxotungstates.

Two enantiotopic 1D chain compounds, [Cu3(L1)3(H2O)2(H2W12O40)]·4H2O (1a,b; L1 = 2-(4,6-bis(pyridin-2-yl)pyridin-2-yl)pyridine), crystallizing in the chiral space group P212121 were prepared and spontaneously resolved in the absence of any chiral source. Interestingly, compounds 1a,b can be prepared from a [W7O24](6-) aqueous solution, [(n-C4H9)4N]4[W10O32], or Na10[H2W12O42], but when [H2W12O40](6-) aqueous solution was the starting material, the achiral compound [CuL1]2[H4W12O40]·5H2O (2) was obtained. When a terpyridine ligand (L2) having a coordination mode similar to that of L1 was used, the mesomeric dimer [Cu3(L2)3(H2O)(H2W12O40)]2·4H2O (3) was obtained from [W7O24](6-) aqueous solution or Na10[H2W12O42], but from [H2W12O40](6-) aqueous solution only compound [Cu2(L2)2Cl2]2[W10O32] (4) was isolated. It is notable that in compounds 1a,b and 3 the symmetry of the α-[H2W12O40](6-) cluster is broken by asymmetric coordination with metal-organic units in a similar mode. As the asymmetric subunit based on a tridecorated [H2W12O40](6-) cluster can be obtained from several isopolyoxotungstate sources except for [H2W12O40](6-), we speculate that the symmetry breaking of α-[H2W12O40](6-) depends on the transformation of isopolyoxotungstates. Furthermore, during the transformation a possible reaction intermediate as the precursor for 1a,b, compound [Cu3(L1)3(H2O)3(H4W11O38)] (5), has been presented and characterized by density functional theory (DFT) calculations.

Optimized pregelatinized starch technique for cell block preparation in cell cultures.

The aim of the present study was to optimize the pregelatinized starch technique for cell block preparation and apply this approach in cultured cells of all types of growing forms, suspension and adherent. In order to evenly mix the starch powder and the cell suspension, we crafted a special plastic dropper. To prove the effectiveness of this optimized technique we used different cell lines, NCI-H69, NCI-H345, HCT-116, SKBR3 and MDA-MB-231. The morphology features, immunocytochemistry (ICC) and fluorescent/chromogenic in-situ hybridization (FISH/CISH) on the cell block sections were evaluated. The morphology features, the ICC and ISH results of cell block sections prepared by the new method were satisfactory comparing with the results obtained in biopsies, the gold standard test for this kind of analysis. The most attractive advantage of our optimized pregelatinized starch technique is that this new method is based on cell suspensions instead of cell sediment, so with our technique every section will contain cells due to the even distribution of the starch powder and the cells forming a homogeneous cell block. To the authors' knowledge, this is the first description on cell block preparation based on cell suspension.

Transformation from [W6O19](2-) to [W6O22](8-) stabilized by Cu(II) complexation.

A rare [W6O22](8-) fragment has been first captured in aqueous solution of [W6O19](2-) by using a transition-metal complex and isolated as a new compound [Cu4(W6O22)(L1)2(H2O)2]·2H2O (1; L1 = 2-amino-4,6-bis(2-pyridyl)pyrimidine), indicating that [W6O19](2-) could also transform to [W6O22](8-) in aqueous solution besides the earlier proven ψ-metatungstates, [W10O32](4-), ß-[(H2)W12O40](6-) and [W7O24](6-).

Structural diversity of silver(I) 4,6-dipyridyl-2-aminopyrimidine complexes: effect of counteranions and ligand isomerism.

Using two ligands, 4,6-bis(2-pyridyl)-2-aminopyrimidine (L1) with two N,N'-chelating sites and 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (L2) (as the isomer of L1) containing one chelating site and one bridging unit, a series of novel Ag(I) complexes varying from zero- to two-dimensions have been prepared and their crystal structures determined via single-crystal X-ray diffraction. The two ligands are employed for the first time in coordination chemistry. The structures of compounds 1-3 are directed by the counteranions adopted in the reaction system: The reaction of L1 with AgNO3 yielded a dimer [Ag2L12](NO3)2 (1). The reaction of L1 with AgCF3SO3 led to a one-dimension "V-shaped" chain {[AgL1](CF3SO3)}n (2). When AgSCN was used, a one-dimension ladder {[Ag2L1(SCN)2].H2O}n (3) was obtained. While ligand L2 reacted with AgNO3, a two-dimension {[Ag2(L2)2](NO3)2.H2O}n (4) was prepared with the help of an argentophilic interaction. Compounds 1-4 display room-temperature photoluminescence.