نتایج جستجو برای: tetra

تعداد نتایج: 9109  

2010
Donia Zaouali Zgolli Habib Boughzala Ahmed Driss

In the title manganese(III) complex, [MnCl(2)(C(10)H(24)N(4))]BF(4) or trans-[MnCl(2)(cyclam)]BF(4) (cyclam is the tetra-dentate amine ligand 1,4,8,11-tetra-azacyclo-tetra-deca-ne), the Mn(III) ions occupy the center of a distorted octa-hedron coordinated by all four ligand nitro-gen donors in the macrobicyclic cavity and two chloride ions occupy the axial positions. Intra-molecular hydrogen bo...

Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-Bu...

2010
Fang-Ming Wang Chang-Sheng Lu Yi-Zhi Li Qing-Jin Meng

In the title compound, tetra-kis[μ(3)-(2-pyrid-yl)methano-lato]tetra-kis[bromido(methanol)cobalt(III)] tetra-bromide 2-(hydroxy-meth-yl)pyridine tetra-solvate dihydrate, [Co(4)Br(4)(C(6)H(6)NO)(4)(CH(3)OH)(4)]Br(4)·4C(6)H(7)NO(4)·2H(2)O, the cation comprises a [Co(4)O(4)] cubane-type core ( symmetry). The four Co(III) ions and bridging O atoms from four (2-pyrid-yl)methano-late anions are locat...

2012
K. LINEK J. ALFÖLDI T. STACH V. PÄTOPRSTÝ

N-Acetylation of (2,3,4,6-tetra-O-acetyl-a-D-glucopyranosyl) (2,3,4,6-tetra-0-acetyl-/?-D-glucopyranosyl)amine or bis(2,3,4,6-tetra-0-acetyl-/3-D-glucopyranosyl)amine afforded N-acetyl-bis(2,3, 4,6-tetra-0-acetyl-/3-D-glucopyranosyl)amine; deacetylation of the latter gave Af-acetyl-di-/3-Dglucopyranosylamine. Similarly, TV-acetylation of bis(2,3,4-tri-0-acetyl-/3-L-rhamnopyranosyl)amine led to ...

2015
Jeonghoo H. Lee Ji Hoon Kang Sung-Chul Lim Seung-Tae Hong

The previously unknown crystal structure of barium perchlorate anhydrate, determined and refined from laboratory X-ray powder diffraction data, represents a new structure type. The title compound was obtained by heating hydrated barium perchlorate [Ba(ClO4)2·xH2O] at 423 K in vacuo for 6 h. It crystallizes in the ortho-rhom-bic space group Fddd. The asymmetric unit contains one Ba (site symmetr...

2010
Mohamed Azrour Brahim Elouadi Lahcen El Ammari

Single crystals of lithium zinc vanadate, LiZnVO(4), were grown by the flux method. The structural type of this vanadate is characterized by a three-dimensional arrangement of tetra-hedra sharing apices in an LiZnVO(4) network. This arrangement contains three different tetra-hedra, namely one [VO(4)] and two disordered mixed-site [Li/ZnO(4)] tetra-hedra. The resulting lattice gives rise to hexa...

2017
Seul Gi Lee Ji Yeon Ryu Junseong Lee

The title compound, C10H10N4O3, was synthesized by the esterification of hy-droxy-phenyl tetra-zole. There is an intra-molecular O-H⋯N hydrogen bond present involving the hy-droxy group and the tetra-zole ring. The tetra-zole ring is inclined to the phenol ring by 2.85 (13)°, while the methyl acetate group is almost normal to the tetra-zole ring, making a dihedral angle of 82.61 (14)°. In the c...

2012
Myrvete Tafili-Kryeziu Kurt Mereiter Wolfgang Linert Franz Werner

The crystal structure of the title compound, C(15)H(14)N(4), contains chains of coplanar tetra-zole rings with the chain direction along b. These are formed through weak hydrogen bonds, donated by the tetra-zole H atoms and by one of the H atoms of the methyl-ene group, and accepted by two neighbouring N atoms of the adjacent tetra-zole ring. The chains are connected to each other in a staircas...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1990
C R Woese S Winker R R Gutell

The four-base loops that cap many double-helical structures in rRNA (the so-called "tetra-loops") exhibit highly invariant to highly variable sequences depending upon their location in the molecule. However, in the vast majority of these cases the sequence of a tetra-loop is independent of its location and conforms to one of three general motifs, GNRA, UNCG, and (more rarely) CUUG. For the most...

2018
Mouhamadou Birame Diop Libasse Diop Allen G Oliver

The title compound, (C21H20OP)(C19H15N4)[CuCl4], was obtained by reacting CuCl2·2H2O with a mixture of one equivalent of acetonyltri-phenyl-phospho-nium chloride and one equivalent of 2,3,5-tri-phenyl-tetra-zolium chloride in aceto-nitrile. In the structure, the Cu centre in the dianion is bonded to four chloride ligands and adopts a distorted tetra-hedral geometry. The phospho-nium cation like...

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