Search results for "Oct"
showing 10 items of 3052 documents
Crystal structure of copper(II) cimetidine sulphate nonahydrate. Cation distortion and structure isomerism in three copper(II) cimetidine complexes
1988
Abstract In the crystalline state, the complex [Cu(CM) 2 ]SO 4 ·9H 2 O (CM = cimetidine) is constituted of two-dimensional cations[Cu(CM) 2 2+ ] n separated by SO 4 2− anions and water molecules. As in the related complexes [Cu(CM) 2 ](ClO 4 ) 2 and [Cu(CM) 2 ](NO 3 ) 2 , the copper atom lies in a strongly distorted octahedral CuN 4 S 2 environment. The distortion is quite different from one complex to another (cation distortion isomerism). In the title compound the CuS bond is unusually long (2.91 A). Unlike the title compound, the [Cu(CM) 2 2+ ] n cations in the perchlorate and nitrate salts are one-dimensional infinite chains characterized by different conformations of the cimetidine mo…
Bromide hydrogen oxalate salts with the diprotonated 1,4-diazabicyclo[2.2.2]octane counterion
2020
Abstract Two new salts composed of the diprotonated 1,4-diazabicyclo[2.2.2]octane (DABCO) molecule as the cations and bromide and hydrogen oxalate as the anions have been isolated and structurally characterized by X-ray diffraction analysis. The salt [DABCOH2]{[HC2O4][Br]} (1) crystallizes in the orthorhombic system, space group P212121 with a = 9.0809(7), b = 9.5156(7), c = 12.3558(9) Å, V = 1067.67(14) Å3 and Z = 4. The salt [DABCOH2]2{[HC2O4][Br]3}·H2O (2) crystallizes in the orthorhombic system, space group Pnma with a = 26.6554(17), b = 7.3711(4), c = 10.7421(7) Å, V = 2110.6(2) Å3 and Z = 4. The compounds were prepared from ethanolic solutions of [DABCOH2][HC2O4]2 (L 1 ) and ZnBr2 in …
Model Pumices Supported Metal Catalysts
1997
The catalyzed, selective hydrogenation, in liquid phase, of 1,3-cyclooctadiene was studied on a series of Pd catalysts supported on natural pumice, model pumices (with variable content of alkali metal ions), silica, and sodium-doped silica. At constant pressure of H2(1 atm.) the reaction follows a zero-order kinetic for all the Pd catalysts. At low metal dispersion (Dx < 20%), Pd/pumice catalysts exhibit higher activity as compared to Pd/silica catalysts; the turnover frequency is maintained even at high metal dispersion in Pd/pumice but Pd/silica and Pd/model pumices without alkali ions show a decrease in activity. At increasingDx, the binding energy shift of Pd 3dlevel is negative in Pd/p…
Synthesis and pharmacological evaluation of enantiomerically pure endo-configured KOR agonists with 2-azabicyclo[3.2.1]octane scaffold
2021
Conformationally restricted bicyclic KOR agonists 10 with an endo configured amino moiety were synthesized to analyze the bioactive conformation of conformationally flexible KOR agonists such as 2-5. A seven-step, chiral pool synthesis starting with (S)-configured 4-oxopiperidine-2-carboxylate 13 was developed. cis and trans configured diesters 12 were obtained in a 3:1 ratio via hydrogenation of the α,β unsaturated ester 14. After establishment of the bicyclic scaffold, a diastereoselective reductive amination of ketone 11 provided exclusively the endo configured bicyclic amines 10a,b. The 3:1 mixtures of enantiomers were separated by chiral HPLC, respectively, leading to enantiomerically …
Synthesis, Structure and Catalytic Properties of Dinuclear Mo-VI Complexes with Ditopic Diaminotetraphenols
2013
MoVI complexes with novel ditopic diaminotetraphenol ligands have been prepared by using a one-pot procedure in methanol or DMSO with [MoO2(acac)2] (acac = acetylacetonate) as the molybdenum source. The complexes were characterised with X-ray diffraction, NMR spectroscopic studies, elemental analysis and IR spectroscopy. In the solid state, the compounds represent either a rodlike molecular or oxido-bridged polymeric structure. The catalytic activity of the complexes was investigated by oxidising benzyl alcohol and 1-phenylethanol with hydrogen peroxide to the corresponding aldehyde and ketone, respectively. Furthermore, the catalytic activity was surveyed also in epoxidation of cyclooctene.
Synthesis, crystal structure and properties of two acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) complexes: bis(5-acetamidato- 1,3,4-th…
1992
Abstract The diverse coordination chemistry exhibited by acetazolamide (H2acm), a potent inhibitor of the carbonic anhydrase metalloenzyme, is highlighted in two new copper(II) complexes of this ligand: [Cu(Hacm)2(en)2] (I) and [Cu(Hacm)2(tn)2] (II). The synthesis, crystal structure and spectroscopic properties of both compounds are reported in this paper. The structures of both compounds consist of discrete units of [Cu(Hacm)2(en)2] (I) and [Cu(Hacm)2(tn)2] (II), respectively, interacting through van der Waals contacts and hydrogen bonds only. Hacm, however, binds differently in each compound. In both cases, the Cu(II) ions, lying on the symmetry centers, show an elongated octahedral geome…
Discrete unusual mixed-bridged trinuclear CoIII2CoII and pentanuclear NiII coordination complexes supported by a phenolate-based ligand: theoretical …
2021
Two new complexes [CoIII2CoII(μ-OL)2(μ-OOCCH3)2(μ-N3)2(N3)2]·Et2O (1·Et2O) and [NiII5(μ-OL)4(μ-OOCCH3)2(OOCCH3)2(μ-N3)2]·CH3CN (2) (HOL = 2-((2-(pyridin-2-yl)ethylamino)methyl)phenol) have been synthesized and characterized by elemental analysis, IR, and UV/Vis spectroscopy. Structural analysis revealed that 1 is a discrete trinuclear and 2 is a discrete pentanuclear coordination complex. In complex 1, terminal metal (CoIII) is in a distorted octahedral MN4O2 environment where coordination is satisfied by two nitrogen atoms and one oxygen atom of the ligand, and an oxygen atom from the acetate group and two nitrogen atoms from azide (one each from the bridging and terminal ones). The centra…
Synthesis and X-Ray Single Crystal Structure of Two New Copper Complexes with the Redox Active Ligand 1,10-Phenanthroline-5,6-dione
2005
The synthesis and the crystal structures of the complexes [Cu(LI)2](ClO4) (1) and [Cu(LI)(CH3CN)2(ClO4)2] (2) are reported. 1 crystallizes in the monoclinic space group C2/c with the unit cell dimensions a = 13.169(4), b = 12.289(3), c = 14.732(3) A, β = 109.03(2)° and Z = 4. Copper(I) is coordinated to four N atoms of the two 1,10-Phenanthroline-5,6-dione (LI) ligands with a two-fold axis passing between the ligands. The copper(II) compound 2 crystallizes in the orthorhombic space group Pbn21 with unit cell dimensions of a = 7.498(5), b = 23.492(7), c = 12.363(4) A and Z = 4. Copper(II) coordination can be described as a distorted octahedron with the N donor atoms of one LI ligand and of t…
Bicyclo[2.2.2]octane-1,4-dicarboxylic acid: towards transparent metal–organic frameworks
2017
The preparation of transparent porous materials can offer a different access towards the study of molecules under solid confined space. Metal-organic frameworks represent a unique opportunity due to their tunable pore size, however aromatic linkers present strong absorption and reduce the transparency. Herein, we report the first example of a MOF with bicyclic organic dicarboxylic linkers and its use as a solid solvent.
A distorted honeycomb motif in divalent transition metal compounds based on 4-phosphonbenzoic acid and exchange coupled Co(II) and Cu(II): synthesis,…
2013
The first example of a two-dimensional inorganic hybrid material with cobalt as an open-shell transition metal ion and 4-phosphonbenzoic acid as a linker is presented together with its copper analogue. For both metal ions the inorganic part consists of edge-sharing metal–oxygen octahedra leading to a metal honeycomb motif. The magnetic properties of the cobalt compound are reported together with those of the corresponding copper compound based on the remarkably six-coordinated copper(II) ions.