Synthesis of B4C/Al-B4C/TiB2 Composite with a Two-Layer Structure

2011 ◽  
Vol 194-196 ◽  
pp. 1703-1706 ◽  
Author(s):  
Xin Yan Yue ◽  
Hong Qiang Ru ◽  
Cui Ping Zhang ◽  
Wei Wang
Keyword(s):  
Porous Layer ◽  
Hot Pressing ◽  
Layer Structure ◽  
Liquid Aluminum ◽  
Three Dimensional ◽  
Interfacial Bonding ◽  
Dimensional Network

A two-layer structure composite based on B4C/Al-B4C/TiB2was prepared using hot pressing and infiltration aluminum in vacuum. The results showed that the B4C porous layer in the two-layer preform looked like a three-dimensional network of interconnected capillaries which could promote the infiltration of liquid aluminum. In the B4C/TiB2layer the TiB2dispersed homogenously in B4C matrix. After infiltrating process the two-layer B4C/Al-B4C/TiB2composite with good interfacial bonding was obtained.

Formation of Nickel(II) Coordination Polymers by a Double Betaine: [{Ni(L)(H2O) 2} n] Cl2n.2nH2O and [{Ni(L)2(H2O)2} n

1997 ◽  
Vol 50 (1) ◽  
pp. 85 ◽  
Author(s):  
Ping-Rong Wei ◽  
De-Dong Wu ◽  
Bo-Mu Wu ◽  
Thomas C. W. Mak
Keyword(s):  
Layer Structure ◽  
Three Dimensional ◽  
Distorted Octahedral Geometry ◽  
Zigzag Chain ◽  
X Ray Crystallography ◽  
Metal Atoms ◽  
Dimensional Network ◽  
Distorted Octahedral ◽  
Network Complex ◽  
Double Betaine

Two novel polymeric nickel(II) complexes of a double betaine with a rigidtris(ethylene) bridge between the pair of nitrogen atoms, namely [ {Ni(L)(H2O)4 }n]Cl2n.2nH2O(1)and [ {Ni(L)2(H2O)2} n](ClO4)2n.4nH2O(2) [L =¯O2CCH2N+(CH2CH2)3N+CH2CO2¯], have been prepared and characterized by X-ray crystallography. Thenickel(II) atom in either complex is coordinated by unidentate carboxylategroups and aqua ligands in a distorted octahedral geometry. The crystalstructure of (1) features an infinite zigzag chain composed of an alternatearrangement of metal atoms and double betaine ligands, and hydrogen bondingamong adjacent chains leads to a three-dimensional network. Complex (2)exhibits a wave-like layer structure corresponding to the (2 0 0) family ofplanes.

scholarly journals Single-crystal structure determination of two new ternary bismuthides: Rh6Mn5Bi18 and RhMnBi3

2018 ◽  
Vol 74 (7) ◽  
pp. 863-869 ◽  
Author(s):  
Peter Kainzbauer ◽  
Klaus W. Richter ◽  
Herta Silvia Effenberger ◽  
Martin C. J. Marker ◽  
Herbert Ipser
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
Layer Structure ◽  
Three Dimensional ◽  
Van Der Waals Interactions ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Dimensional Network ◽  
Pearson Symbol

A study of the ternary Rh–Mn–Bi phase diagram revealed the existence of two new ternary bismuthides, viz. hexarhodium pentamanganese octadecabismuthide (Rh6Mn5Bi18) and rhodium manganese tribismuthide (RhMnBi3). Their crystal structures represent new structure types. Rh6Mn5Bi18, with a Wyckoff sequence a f2 g2 i5, crystallizes in the tetragonal system (space group P42/mnm; Pearson symbol tP58), and RhMnBi3, with a Wyckoff sequence a c g i q, crystallizes in the orthorhombic system (Cmmm; oS20). In the Rh6Mn5Bi18 structure, the transition metal atoms are linked into ribbon-like structural units aligned along the [001] direction, whereas planar sheets are formed in RhMnBi3. In both crystal structures, the units formed by the transition metal atoms are enveloped by Bi atoms, which themselves form a loosely bound network. The linkage results in a layer structure for RhMnBi3, while in the case of Rh6Mn5Bi18, a three-dimensional network is formed; the latter, however, contains several areas where Bi...Bi distances suggest van der Waals interactions. Both phases under discussion have analogous structural motifs.

scholarly journals 3-Difluoromethyl-5-[4-(trifluoromethyl)phenyl]isoxazole

IUCrData ◽  
2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Hui Zhao
Keyword(s):  
Hydrogen Bonds ◽  
Layer Structure ◽  
Three Dimensional ◽  
Unit Cell ◽  
Mirror Plane ◽  
Orthorhombic Unit Cell ◽  
Π Interactions ◽  
Dimensional Network ◽  
Title Molecule

The title molecule, C11H6F5NO, lies on a mirror plane in the orthorhombic unit cell, with only two F atoms each of the difluoro and trifluoromethyl substituents lying out of the plane. In the crystal, molecules are linked by C—H...O, C—H...N and C—H...F hydrogen bonds, forming a layer structure parallel to the (001) plane. Weak π–π interactions promote the formation of a three-dimensional network.

N—H...S and C—H...S hydrogen bonds in two tetraalkylammonium dithiobiurea(1–) inclusion compounds

2015 ◽  
Vol 71 (4) ◽  
pp. 242-246 ◽  
Author(s):  
Hao Guo ◽  
Jinfeng Wu
Keyword(s):  
Hydrogen Bonds ◽  
Network Structure ◽  
Inclusion Compounds ◽  
Layer Structure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Host Molecule ◽  
One Dimensional ◽  
Dimensional Network ◽  
Hydrogen Bonded

Two inclusion compounds of dithiobiurea and tetrapropylammonium and tetrabutylammonium are characterized and reported, namely tetrapropylammonium carbamothioyl(carbamothioylamino)azanide, C12H28N+·C2H5N4S2−, (1), and tetrabutylammonium carbamothioyl(carbamothioylamino)azanide, C16H36N+·C2H5N4S2−, (2). The results show that in (1), the dithiobiurea anion forms a dimerviaN—H...N hydrogen bonds and the dimers are connected into wide hydrogen-bonded ribbons. The guest tetrapropylammonium cation changes its character to become the host molecule, generating pseudo-channels containing the aforementioned ribbons by C—H...S contacts, yielding the three-dimensional network structure. In comparison, in (2), the dithiobiurea anions are linkedviaN—H...S interactions, producing one-dimensional chains which pack to generate two-dimensional hydrogen-bonded layers. These layers accommodate the guest tetrabutylammonium cations, resulting in a sandwich-like layer structure with host–guest C—H...S contacts.

A novel two-dimensional cobalt(II) complex composed of one-dimensional twisted pair-like chains: poly[[tetraaquabis(μ3-pyridine-2,5-dicarboxylato-κ4N,O2:O5:O5′)dicobalt(II)] dihydrate]

2014 ◽  
Vol 70 (3) ◽  
pp. 302-305
Author(s):  
Qing-Biao Hou ◽  
Li-Juan Chen ◽  
Jing Guo ◽  
Shen Lin
Keyword(s):  
Layer Structure ◽  
Three Dimensional ◽  
Carboxylate Group ◽  
Two Dimensional ◽  
Twisted Pair ◽  
One Dimensional ◽  
Dimensional Network ◽  
Solvent Molecules ◽  
Neutral Polymer ◽  
Interlamellar Region

A novel neutral polymer, {[Co2(C7H3NO4)2(H2O)4]·2H2O}n, was hydrothermally synthesized using pyridine-2,5-dicarboxylate (2,5-PDC2−) as the organic linker. It features a two-dimensional layer structure constructed from one-dimensional {[Co(2,5-PDC)2]2−}nchains interlinked by [Co(H2O)4]+units. The two CoIIcations occupy special positions, sitting on inversion centres. Each 2,5-PDC2−anion chelates to one CoIIcationviathe pyridine N atom and an O atom of the adjacent carboxylate group, and links to two other CoIIcations in a bridging modeviathe O atoms of the other carboxylate group. In this way, the 2,5-PDC2−ligand connects three neighbouring CoIIcentres to form a two-dimensional network. The two-dimensional undulating layers are linked by extensive hydrogen bonds to form a three-dimensional supramolecular structure, with the uncoordinated solvent molecules occupying the interlamellar region.

CdII and CoII coordination polymers constructed from benzene-1,4-dicarboxylic acid and 2-(pyridin-3-yl)-1H-benzimidazole ligands

2014 ◽  
Vol 70 (5) ◽  
pp. 488-492
Author(s):  
Xiao-Hua Chen ◽  
Hua Huang ◽  
Ming-Xing Yang ◽  
Li-Juan Chen ◽  
Shen Lin
Keyword(s):  
Hydrogen Bonding ◽  
Layer Structure ◽  
Three Dimensional ◽  
Water Molecules ◽  
Dimensional Chain ◽  
One Dimensional ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Complex Forms ◽  
Coordinated Water

In poly[aqua(μ3-benzene-1,4-dicarboxylato-κ5 O 1,O 1′:O 1:O 4,O 4′)[2-(pyridin-3-yl-κN)-1H-benzimidazole]cadmium(II)], [Cd(C8H4O4)(C12H9N3)(H2O)] n , (I), each CdII ion is seven-coordinated by the pyridine N atom from a 2-(pyridin-3-yl)benzimidazole (3-PyBIm) ligand, five O atoms from three benzene-1,4-dicarboxylate (1,4-bdc) ligands and one O atom from a coordinated water molecule. The complex forms an extended two-dimensional carboxylate layer structure, which is further extended into a three-dimensional network by hydrogen-bonding interactions. In catena-poly[[diaquabis[2-(pyridin-3-yl-κN)-1H-benzimidazole]cobalt(II)]-μ2-benzene-1,4-dicarboxylato-κ2 O 1:O 4], [Co(C8H4O4)(C12H9N3)2(H2O)2] n , (II), each CoII ion is six-coordinated by two pyridine N atoms from two 3-PyBIm ligands, two O atoms from two 1,4-bdc ligands and two O atoms from two coordinated water molecules. The complex forms a one-dimensional chain-like coordination polymer and is further assembled by hydrogen-bonding interactions to form a three-dimensional network.

scholarly journals Crystal structure of 3-[2-(1,3-thiazol-2-yl)diazen-1-yl]pyridine-2,6-diamine monohydrate

2018 ◽  
Vol 74 (4) ◽  
pp. 563-565 ◽  
Author(s):  
Ratanon Chotima ◽  
Bussaba Boonseng ◽  
Akkharadet Piyasaengthong ◽  
Apisit Songsasen ◽  
Kittipong Chainok
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Hydrogen Bonds ◽  
Organic Molecule ◽  
Layer Structure ◽  
Three Dimensional ◽  
Azo Compound ◽  
Compound C ◽  
Dimensional Network ◽  
The Mean

In the title hydrated azo compound, C8H8N6S·H2O, the two aromatic groups are close to coplanar with the dihedral angle between the mean planes of the thiazole and pyridine rings being 2.9 (2)°. The organic molecule adopts an E configuration with respect to the double bond of the azo bridge. In the crystal, molecules are linked by (amine)N—H...N(pyridine), (amine)N—H...O(water) and (water)O—H...N(thiazole) hydrogen bonds along with π–π interactions involving pairs of thiazole rings and pairs of pyridine rings. The plane-to-plane distance between two parallel molecules is 3.7856 (4) Å and corresponds to the length of the a axis. In this way, a layer structure parallel to (010) is formed. The layers are linked by weak C—H...S hydrogen bonds, eventually resulting in a three-dimensional network.

Development of Mucoadhesive Buccal Drug Delivery System of Propranolol Hydrochloride Using Aster ericoides Mucilage

2020 ◽  
Vol 10 (2) ◽  
pp. 133-148
Author(s):  
Ankaj Kaundal ◽  
Pravin Kumar ◽  
Rajendra Awasthi ◽  
Giriraj T. Kulkarni
Keyword(s):  
Buccal Cavity ◽  
Three Dimensional ◽  
Hot Water ◽  
Fickian Diffusion ◽  
Aster Ericoides ◽  
Dimensional Network ◽  
Buccal Tablet ◽  
Significant Difference ◽  
Volunteer Group

Aim: The study was aimed to develop mucoadhesive buccal tablets using Aster ericoides leaves mucilage. Background : Mucilages are naturally occurring high-molecular-weight polyuronides, which have been extensively studied for their application in different pharmaceutical dosage forms. Objective: The objective of the present research was to establish the mucilage isolated from the leaves of Aster ericoides as an excipient for the formulation of the mucoadhesive buccal tablet. Method: The mucilage was isolated from the leaves of Aster ericoides by maceration, precipitated with acetone and characterized. Tablets were prepared using wet granulation technique and evaluated for various official tests. Results: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Conclusion: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Other: However, to prove the potency of the polymer, in vivo bioavailability studies in human volunteers are needed along with chronic toxicity studies in suitable animal models.

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