نتایج جستجو برای: penta
تعداد نتایج: 2468 فیلتر نتایج به سال:
Based on first-principles calculations, we predict that penta-twinned Cu nanowires (NWs) are superior to conventional Cu catalysts for CO2 electroreduction. The penta-twinned NWs possess a combination of ultrahigh mechanical strength, large surface-to-volume ratios and an abundance of undercoordinated adsorption sites, all desirable for CO2 electroreduction. In particular, we show that the pent...
The title compound, C(19)H(10)F(5)NO(2), was synthesized by the 1:1 condensation of 2-methyl-8-hydroxy-quinaldine with penta-fluoro-benzaldehyde. It crystallizes with two almost identical mol-ecules in the asymmetric unit. The penta-fluoro-benzene ring is essentially coplanar with the quinoline ring, forming dihedral angles of 2.49 (17) and 8.72 (16)° in the two mol-ecules.
An efficient three-step synthesis of d-mannoheptulose was successfully accomplished from 2,3,4,5,6-penta-O-benzyl-d-mannose. First, an olefinated sugar was prepared from 2,3,4,5,6-penta-O-benzyl-d-mannose via a Wittig reaction. Second, the key step, a 2-hydroxyoxirane product was unexpectedly obtained by oxidation of the olefinated sugar with potassium permanganate in aqueous acetone. Finally d...
The title dinuclear titanocene, [Ti(2)(C(8)H(9)O)(C(18)H(25)Si)(2)Cl(3)O], contains one Ti atom tetra-hedrally coordinated by two Cl atoms, a bridging O atom and the substituted cyclo-penta-dienyl ligand, and another Ti atom tetra-hedrally coordinated by a Cl atom, a bridging O atom, the 2,6-dimethyl-phenolate ligand and the substituted cyclo-penta-dienyl ligand. The bridging O atom lies on a t...
In the title compound, [Fe(C5H5)(C14H10NO3)], the cyclo-penta-dienyl rings are in an eclipsed conformation and the pyran ring adopts a half-chair conformation. The mean plane of the pyran ring makes dihedral angles of 79.33 (1) and 80.73 (1)°, respectively, with the substituted and unsubstituted cyclo-penta-dienyl rings. In the crystal, pairs of C-H⋯O hydrogen bonds link the mol-ecules into inv...
In the title compound, [Fe(C(5)H(5))(C(21)H(20)NO(5))], the pyrrolidine and cyclo-penta-none rings exhibit a twist conformation. The pyrrolidine ring is almost perpendicular to the cyclo-penta-none ring, making a dihedral angle of 81.91 (6)°. The mol-ecular conformation is stabilized by an intra-molecular O-H⋯N hydrogen bond and C-H⋯O inter-actions. The crystal structure is stabilized by inter-...
The mol-ecule of the title compound, C(66)H(40)F(6)·CH(2)Cl(2), is centrosymmetric; the dihedral angle between the central fluorinated unit and the cyclo-penta-diene ring is 88.36 (7)°. The dihedral angles between the cyclo-penta-diene ring and the four surrounding phenyl rings are in the range 26.6 (1)-65.6 (1)°. Centrosymmetric cavities in the crystal structure are populated by disordered dic...
The title compound, [Fe(C(5)H(5))(C(8)H(9)S)(CO)(2)], is a three-legged piano-stool iron(II) complex that is characterized by a thio-ethyl-linked phenyl ring and a cyclo-penta-dienyl moiety that occupies the apical coordination site. The two aromatic rings are essentially planar with the same maximum deviation of 0.009 Å. The mean planes of the phenyl and cyclo-penta-dienyl rings bis-ect at an ...
Metal-free and environmentally friendly synthesis highly controlled by natural sources like visible light and air (or oxygen) is always a pursuit of green chemistry. In this paper, an atmosphere and light tuned highly diastereoselective synthesis of two important polyheterocyclic skeletons: cyclobuta/penta[b]indoles from aniline-tethered alkylidenecyclopropanes with alkynes, has been developed....
A contemporaneidade, marcada por um mercado de emprego flexível e competitivo, exige que os jovens, nomeadamente universitários, sejam capazes gerir a sua carreira. Para profissionais carreira consigam auxiliar estes precisam ter à disposição instrumentos válidos fiáveis lhes possibilitem avaliar comportamentos carreira, como as respostas adaptativas. Este estudo tem objetivo analisar proprieda...
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