333 research outputs found
μ 3-Oxido-hexa-μ 2-pivalato-tris[(methanol-κO)cobalt(III)] chloride
The crystal structure of the title compound, [Co3(C5H9O2)6O(CH4O)3]Cl, consists of trinuclear CoIII complex cations and chloride anions. The CoIII cation has site symmetry m, and is coordinated by four oxygen atoms from four bridging pivalate groups, one central O anion and a methanol oxygen atom, forming a distorted octahedral geometry. The coordinated methanol molecule is located on a crystallographic special position, the C and O atoms being located on the mirror plane. The central O anion lies in the crystallographic position, and acts as a μ
3-O bridge, linking three equivalent CoIII cations and generating the oxo-centered trinuclear CoIII complex. The chloride anion, which acts as the counter-ion, is located on crystallographic position. O—H⋯Cl hydrogen bonding between the Cl anion and hydroxyl group of the coordinated methanol molecule links the molecules into a supramolecular network
Bis{μ-2-[1-(2-Pyridylmethylimino)ethyl]phenolato}bis[azidocopper(II)]
The title compound, [Cu2(C14H13N2O)2(N3)2], was synthesized by the reaction of Cu(NO3)2·3H2O with the Schiff base 2-[1-(2-pyridylmethylimino)ethyl]phenol (HL) in methanol–water solution, adding NaN3 as the bridging ligand. The asymmetric unit contains one half-molecule, the other half being generated by the inversion center. Each CuII atom shows a slightly distorted trigonal-pyramidal geometry formed by two N atoms and one O atom from one Schiff base ligand, by another O atom of a second Schiff base ligand and by an azide N atom. The crystal structure is stabilized by intermolecular C—H⋯N hydrogen bonds
4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-[2-(2-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-3-yl)ethyl]piperidinium nitrate
In the risperidone cation of the title compound, C23H28FN4O2
+·NO3
−, the piperidine ring adopts a chair conformation and the tetrahydropyridine ring is disordered over two orientations in a 0.620 (11):0.380 (11) ratio. N—H⋯O, C—H⋯O and C—H⋯F hydrogen bonds are present in the crystal structure
Pathogen-origin horizontally transferred genes contribute to the evolution of Lepidopteran insects
<p>Abstract</p> <p>Background</p> <p>Horizontal gene transfer (HGT), a source of genetic variation, is generally considered to facilitate hosts' adaptability to environments. However, convincing evidence supporting the significant contribution of the transferred genes to the evolution of metazoan recipients is rare.</p> <p>Results</p> <p>In this study, based on sequence data accumulated to date, we used a unified method consisting of similarity search and phylogenetic analysis to detect horizontally transferred genes (HTGs) between prokaryotes and five insect species including <it>Drosophila melanogaster</it>, <it>Anopheles gambiae</it>, <it>Bombyx mori</it>, <it>Tribolium castaneum </it>and <it>Apis mellifera</it>. Unexpectedly, the candidate HTGs were not detected in <it>D. melanogaster</it>, <it>An. gambiae </it>and <it>T. castaneum</it>, and 79 genes in <it>Ap. mellifera </it>sieved by the same method were considered as contamination based on other information. Consequently, 14 types of 22 HTGs were detected only in the silkworm. Additionally, 13 types of the detected silkworm HTGs share homologous sequences in species of other Lepidopteran superfamilies, suggesting that the majority of these HTGs were derived from ancient transfer events before the radiation of Ditrysia clade. On the basis of phylogenetic topologies and BLAST search results, donor bacteria of these genes were inferred, respectively. At least half of the predicted donor organisms may be entomopathogenic bacteria. The predicted biochemical functions of these genes include four categories: glycosyl hydrolase family, oxidoreductase family, amino acid metabolism, and others.</p> <p>Conclusions</p> <p>The products of HTGs detected in this study may take part in comprehensive physiological metabolism. These genes potentially contributed to functional innovation and adaptability of Lepidopteran hosts in their ancient lineages associated with the diversification of angiosperms. Importantly, our results imply that pathogens may be advantageous to the subsistence and prosperity of hosts through effective HGT events at a large evolutionary scale.</p
Aqua(1,10-phenanthroline-κ2 N,N′)bis(trimethylacetato)-κ2 O,O′;κO-cobalt(II)
In the title compound, [Co(C5H9O2)2(C12H8N2)(H2O)], the CoII atom is coordinated in a distorted octahedral environment by three carboxyl O atoms of two trimethylacetate ligands, one aqua O atom and two N atoms from 1,10-phenanthroline. The crystal structure is stabilized by O—H⋯O hydrogen bonds and π–π stacking interactions [interplanar distance between interdigitating 1,10-phenanthroline ligands = 3.378 (2) Å]
Aquabis(2-methyl-4-oxopyrido[1,2-a]pyrimidin-9-olato)zinc(II) monohydrate
The crystal structure of the title compound, [Zn(C9H7N2O2)2(H2O)]·H2O, involves discrete mononuclear complex molecules. The special positions on the rotation twofold axis are occupied by ZnII and O atoms of the coordinated and uncoordinated water molecules. The coordination around the ZnII atom can be described as transitional from trigonal-bipyramidal to square-pyramidal. The two chelating 2-methyl-4-oxopyrido[1,2-a]pyrimidin-9-olate ligands and the coordinated water molecule form the Zn coordination. O—H⋯O hydrogen bonds between the coordinated water molecule and the ligand and between the uncoordinated water molecule and the ligand dominate the crystal packing
Modulation of the thermodynamic, kinetic and magnetic properties of the hydrogen monomer on graphene by charge doping
The thermodynamic, kinetic and magnetic properties of the hydrogen monomer on
doped graphene layers were studied by ab initio simulations. Electron doping
was found to heighten the diffusion potential barrier, while hole doping lowers
it. However, both kinds of dopings heighten the desorption potential barrier.
The underlying mechanism was revealed by investigating the effect of doping on
the bond strength of graphene and on the electron transfer and the coulomb
interaction between the hydrogen monomer and graphene. The kinetic properties
of H and D monomers on doped graphene layers during both the annealing process
(annealing time 300 s) and the constant-rate heating process (heating
rate 1.0 K/s) were simulated. Both electron and hole dopings were
found to generally increase the desorption temperatures of hydrogen monomers.
Electron doping was found to prevent the diffusion of hydrogen monomers, while
the hole doping enhances their diffusion. Macroscopic diffusion of hydrogen
monomers on graphene can be achieved when the doping-hole density reaches
cm. The magnetic moment and exchange splitting were
found to be reduced by both electron and hole dopings, which was explained by a
simple exchange model. The study in this report can further enhance the
understanding of the interaction between hydrogen and graphene and is expected
to be helpful in the design of hydrogenated-graphene-based devices.Comment: Submitte
- …