Search results for "Hexagonal crystal system"
showing 10 items of 39 documents
2D and 3D Anilato-Based Heterometallic M(I)M(III) Lattices: The Missing Link
2015
The similar bis-bidentate coordination mode of oxalato and anilato-based ligands is exploited here to create the first examples of 2D and 3D heterometallic lattices based on anilato ligands combining M(I) and a M(III) ions, phases already observed with oxalato but unknown with anilato-type ligands. These lattices are prepared with alkaline metal ions and magnetic chiral tris(anilato)metalate molecular building blocks: [M(III)(C6O4X2)3](3-) (M(III) = Fe and Cr; X = Cl and Br; (C6O4X2)(2-) = dianion of the 3,6-disubstituted derivatives of 2,5-dihydroxy-1,4-benzoquinone, H4C6O4). The new compounds include two very similar 2D lattices formulated as (PBu3Me)2[NaCr(C6O4Br2)3] (1) and (PPh3Et)2[KF…
Subcellular duplex DNA and G‐quadruplex interaction profiling of a hexagonal PtII metallacycle
2019
[Abstract] Metal‐driven self‐assembly afforded a multitude of fascinating supramolecular coordination complexes (SCCs) with applications as catalysts, host–guest, and stimuli‐responsive systems. However, the interest in the biological applications of SCCs is only starting to emerge and thorough characterization of their behavior in biological milieus is still lacking. Herein, we report on the synthesis and detailed in‐cell tracking of a Pt2L2 metallacycle. We show that our hexagonal supramolecule accumulates in cancer cell nuclei, exerting a distinctive blue fluorescence staining of chromatin resistant to UV photobleaching selectively in nucleolar G4‐rich regions. SCC co‐localizes with epit…
MICRO- AND NANO-STRUCTURES IN SINGLE CRYSTALS OF LITHIUM NIOBATE CONTAINING LANTHANIDE ADMIXTURES
2008
ABSTRACT Micro-size domain structures in lithium niobate single crystals containing lanthanide (Gd, Tm, Sm, Lu) admixture, grown under stationary and non-stationary conditions are studied by efficient and flexible Thixomet® image analyser. Regular fractal-type domain structures observed along the three Y-axes of the hexagonal crystallographic set-up are assigned to pinning of the domain walls at defects created under conditions of imbalanced crystallization of the doped melt. Characteristic types of domains have been found analysing the configurations of domains on optical and atomic force microscopic images of surfaces of different crystallographic orientations.
Nature of the asymmetry in the hydrogen-bond networks of hexagonal ice and liquid water.
2014
The interpretation of the X-ray spectra of water as evidence for its asymmetric structure has challenged the traditional nearly tetrahedral model and initiated an intense debate about the order and symmetry of the hydrogen-bond network in water. Here, we present new insights into the nature of local interactions in ice and liquid water obtained using a first-principle energy decomposition method. A comparative analysis shows that the majority of molecules in liquid water in our simulation exhibit hydrogen-bonding energy patterns similar to those in ice and retain the four-fold coordination with only moderately distorted tetrahedral configurations. Although this result indicates that the tra…
Crystal inclusions in subepithelial fibroblasts of the brood pouch of sea horses (hippocampus kuda)
1968
In the subepithelial connective tissue of the inactive broodpouch of sea horses (Hippocampus kuda), fibroblasts with striking crystal inclusions are described light microscopically and electron microscopically in the tunica adventitia of capillaries. These very electron dense crystals turn out to be hexagonal prisms of heterogeneous structures. Results of the X-ray microanalysis and comparison with other crystalline cell inclusions so far described allow the conclusion that they contain an iron protein stored as crystals. The structure and genesis of these crystals as well as the possible importance of the iron protein for the biology of these animals are discussed.
The effect of Zn vacancies and Ga dopants on the electronic structure of ZnO:Ab initiosimulations
2012
Zinc oxide modied by metal dopants can be used as a low-cost material for production of transparent conducting lms. Its optical and electronic properties vary with the type and the concentration of dopants. In this study we have performed rst-principle calculations on ZnO with Zn vacancies and that with Ga dopants in wurtzite type hexagonal morphology using density functional theory approach. Dependence of the electronic properties on the concentration of dopants has been studied using supercells of dierent sizes.
A fluorescent layered oxalato-based canted antiferromagnet
2018
We report the synthesis and characterization of the first fluorescent oxalato-based canted antiferromagnet. Compound [DOC][MnFe(C2O4)3] (1) (DOC = 3,3'-diethyloxacarbocyanine) combines the well-known canted antiferromagnetic [MnFe(C2O4)3]- honeycomb layers with a fluorescent cationic cyanine-type fluorescent dye. Besides the expected spin canted antiferromagnetic order in the oxalato layer at ca. 29 K, we show the key role played by the anionic oxalato lattice in the optical properties of the cation since it provides isolation of dye cations in the hexagonal cavities of the oxalato-based matrix. The emission of the DOC+ dye shows a redshift and a broadening of the emission as well as an inc…
Smart High-κ Nanodielectrics Using Solid Supported Polyoxometalate-Rich Nanostructures
2011
Utilizing Langmuir-Blodgett deposition and scanning probe microscopy, we have investigated the extent to which cations alter the self-assembly processes of hybrid polyoxometalates (POMs) on surfaces. The well-defined 2D hexagonal nanostructures obtained were extensively characterized and their properties were studied, and this has revealed fascinating dielectric behavior and reversible capacitive properties. The nanostructures are extremely stable under ambient conditions, and yet exhibit fascinating self-patterning upon heating. These findings present POMs as effective smart nanodielectrics and open up a new field for future POM applications. (c) 2011 American Chemical Society.
Texture and Phase Recognition Analysis of beta-NaYF4 Nanocrystals
2014
Texture and phase recognition analysis (TPRA) based on electron nanodiffraction technique is used to characterize the geometry of up-conversion nanocrystals (UCNCs) synthesized by the common thermal-decomposition protocol in the presence of a stoichiometric amount of NH4F. Here, we confirmed experimentally that despite the apparently different shapes of samples (hexagons, rods, and cubes), all the nanocrystals are actually beta-phase hexagonal prisms. This is of relevance since many biological features of nanostructures, such as cellular internalization and cytotoxicity, are governed by their geometry. In addition, reproducibility in biological experiments is paramount.
Supramolecular self-assembling in mesostructured materials through charge tuning in the inorganic phase
1998
Supramolecular self-assembling of organic CTA+ micelles and inorganic [VO(H2O)PO4]n^q-2 2D-anions for the isolation of hexagonal mesostructured materials can be reached by charge tuning in the inorganic phase through the adjustment of the vanadium mean oxidation state. El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Cabrera Medina, Saul, Saul.Cabrera@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Alamo Serrano, Jaime, Jaime.Alamo@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es