Humidity Sensitive Structural Dynamics and Solvatomagnetic Effects in a 3D Co(II)-Based Coordination Polymer.

A chiral Co(II)-based coordination polymer, [Co3(pimda)2(H2O)5] (1, H3pimda = 2-propyl-1H-imidazole-4,5-dicarboxylic acid) with 3D hyperkagomé topology is reported. Upon heating/cooling, the water molecules which are coordinated to a pair of crystallographically symmetric Co(II) ions are removed/recovered discretely in two steps, giving [Co3(pimda)2(H2O)4] (2) and [Co3(pimda)2(H2O)3] (3), which is evidenced by the reversible single-crystal-to-single-crystal (SCSC) structural transformations. As the coordination geometry of the two Co(II) ions changes from octahedron to trigonal bipyramid, obvious color change from pink for 1 to dark violet for 2 and 3 is observed. Further magnetic measurements demonstrate the presence of a solvatomagnetic effect from paramagnets for 1 and 2 to weak ferromagnet for 3. Moreover, as revealed by the variable-temperature crystallographic measurements, the first and second dehydration temperatures could be controlled from 298 K (25 °C) and 383 K (110 °C) sealed in a capillary (high humidity) to 255 K (-18 °C) and 307 K (34 °C) in dry N2 (low humidity), indicating the strong humidity sensitivity of the structural dynamics.

Spin frustration in a family of pillared kagomé layers of high-spin cobalt(II) ions.

Based on the analogous kagomé [Co3 (imda)2 ] layers (imda=imidazole-4,5-dicarboxylate), a family of pillar-layered frameworks with the formula of [Co3 (imda)2 (L)3 ]⋅(L)n ⋅xH2 O (1: L=pyrazine, n=0, x=8; 2: L=4,4'-bipyridine, n=1, x=8; 3: L=1,4-di(pyridin-4-yl)benzene, n=1, x=13; 4: L=4,4'-di(pyridin-4-yl)-1,1'-biphenyl, n=1, x=14) have been successfully synthesized by a hydrothermal/solvothermal method. Single-crystal structural analysis shows a significant increase in the interlayer distances synchronized with the extension of the pillar ligands, namely, 7.092(3) (1), 10.921(6) (2), 14.780(5) (3), and 19.165(4) Š(4). Despite the wrinkled kagomé layers in complexes 2-4, comprehensive magnetic characterizations revealed weakening of interlayer magnetic interactions and an increase in the degree of frustration as the pillar ligand becomes longer from 1 to 4; this leads to characteristic magnetic ground states. For compound 4, which has the longest interlayer distance, the interlayer interaction is so weak that the magnetic properties observed within the range of temperature measured would correspond to the frustrated layer.

Additional four species of Tatraea (Leotiomycetes, Helotiales) in Yunnan Province, China.

During the investigations of discomycetes in Yunnan, China, five species of Tatraea were discovered on decayed, decorticated oak trees or unidentified wood. All species have typical disc-like, large fruiting bodies with grey, brown or greyish-green colors. The ITS sequence analysis showed that they belong to Tatraea (Helotiaceae, Helotiales) and the LSU and ITS combination revealed a different topology within the genus. Four species, T.clepsydriformis, T.griseoturcoisina, T.yunnanensis and T.yuxiensis were established as new species, and T.aseptata was collected and described on oak woods. The pairwise homoplasy index (PHI) test results indicated that there is no significant genetic recombination (Φw = 1.0) between all related species pairs. All the species described here are supported by descriptions, illustrations and multi-gene analyses.

Novel three-dimensional 3d-4f microporous magnets exhibiting selective gas adsorption behavior.

Three microporous Ln-Co-pyta heterometallic compounds [Ln4Co3(pyta)6(H2O)9].5H2O (Ln = Sm (1), Eu (2), Gd (3); H3pyta = 2,4,6-pyridinetricarboxylic acid) have interesting selective adsorption abilities towards H2/N2 and CO2/N2 because of size-selective effects; magnetic analysis reveals that has a ferromagnetic behavior.

Synthesis, Crystal Structure, Spectroscopic Properties, and Interaction with Ct-DNA of Zn(II) with 2-Aminoethanethiol Hydrochloride Ligand.

The zinc(II) complex (C2H6NS)2Zn·ZnCl2 was synthesized with 2-aminoethanethiol hydrochloride and zinc sulfate heptahydrate as the raw materials in aqueous solution. The composition and structure of the complex were characterized by elemental analysis, infrared spectra, single crystal X-ray diffraction, and thermogravimetry. The crystal structure of the zinc(II) complex belongs to monoclinic system, space group P 21/n, with cell parameters of a = 0.84294(4), b = 0.83920(4), c = 1.65787(8) nm, Z = 2, and D = 2.041 g/cm(3). In this paper, the interaction of complex with Ct-DNA was investigated by UV-visible and viscosimetric techniques. Upon addition of the complex, important changes were observed in the characteristic UV-Vis bands (hyperchromism) of calf thymus DNA and some changes in specific viscosity. The experimental results showed that the complex is bound to DNA intercalative (intercalation binding).