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Form N (form + n)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

ChemInform Abstract: Three-Component Reaction of 5,5-Dimethylcyclohexane-1,3-dione, Aromatic Aldehydes, and Acetonitrile in the Presence of Chlorosulfonic Acid Forming N-[(2-Hydroxy-4-4-dimethyl-6-oxocyclohexene-1-yl)-aryl-methyl] -acetamides.

CHEMINFORM, Issue 15 2010
Mohammad Anary-Abbasinejad
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Two concomitant polymorphs of N,N,-bis[4-(diethylamino)phenyl]terephthaldiamide

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2010
Piotr Ku
The title compound, C28H34N4O2, crystallizes simultaneously as a monoclinic, (Im), and a (twinned) triclinic polymorph, (It), from d6 -dimethyl sulfoxide. Polymorph (It) (P, Z = 1) displays the standard `ladder' packing for this group of compounds, with neighbouring inversion-symmetric molecules related by translation and connected by hydrogen bonds of the form N,H...O=C. Polymorph (Im) (Cc, Z = 4) has no imposed symmetry; there are three independent hydrogen bonds, one classical N,H...O=C and a bifurcated system with N,H...O=C augmented by a short C,H...O=C interaction. Each molecule is thereby linked to four neighbouring molecules, two lower and two higher, so that a crosslinked three-dimensional pattern is formed rather than the standard ladder. [source]

Mesoporous Silicas by Self-Assembly of Lipid Molecules: Ribbon, Hollow Sphere, and Chiral Materials

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2008
Haiying Jin
Abstract Using lipids (N -acyl amino acids) and 3-aminopropyltriethoxysilane as structure- and co-structure-directing agents, mesoporous silicas with four different morphologies, that is, helical ribbon (HR), hollow sphere, circular disk, and helical hexagonal rod, were synthesized just by changing the synthesis temperature from 0,°C to 10, 15, or 20,°C. The structures were studied by electron microscopy. It was found that 1),the structures have double-layer disordered mesopores in the HR, radially oriented mesopores in the hollow sphere, and highly ordered straight and chiral 2D-hexagonal mesopores in the disklike structure and helical rod, respectively; 2),these four types of mesoporous silica were transformed from the flat bilayered lipid ribbon with a chain-interdigitated layer phase through a solid,solid transformation for HR formation and a dissolving procedure transformation for the synthesis of the hollow sphere, circular disk, and twisted morphologies; 3),the mesoporous silica helical ribbon was exclusively right-handed and the 2D-hexagonal chiral mesoporous silica was excessively left-handed when the L -form N -acyl amino acid was used as the lipid template; 4),the HR was formed only by the chiral lipid molecules, whereas the 2D-hexagonal chiral mesoporous silicas were formed by chiral, achiral, and racemic lipids. Our findings give important information for the understanding of the formation of chiral materials at the molecular level and will facilitate a more efficient and systematic approach to the generation of rationalized chiral libraries. [source]

Hydrogen-bond motifs in N -monosubstituted derivatives of barbituric acid: 5-allyl-5-isopropyl-1-methylbarbituric acid (enallylpropymal) and 1,5-di(but-2-enyl)-5-ethylbarbituric acid

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2010
Thomas Gelbrich
Both title structures exhibit essentially planar barbiturate rings. The crystal structure of enallylpropymal (5-allyl-5-isopropyl-1-methylbarbituric acid), C11H16N2O3, is composed of centrosymmetric N,H...O hydrogen-bonded dimers, while 1,5-di(but-2-enyl)-5-ethylbarbituric acid, C14H20N2O3, forms N,H...O hydrogen-bonded helical chains. Each of the ten known crystal structures of closely related N -monosubstituted derivatives of barbituric acid displays one of the fundamental N,H...O hydrogen-bonded motifs of the two title structures, i.e. either a dimer or a chain. [source]