Os alcanos son hidrocarburos, é dicir que teñen só átomos de carbono e .. difiren en enerxía: a conformación alternada é 12,6 kJ/mol menor en enerxía (por . Presentación del tema: “Estructura y Estereoquímica de Alcanos”— . Conformaciones son diferentes arreglos de los átomos producidos al rotar el enlace σ. Análisis conformacional del etano Análisis conformacional del butano Mecánica molecular aplicada a los alcanos y los cicloalcanos
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El Cis-1,3-dimetilciclohexano puede tener ambos grupos axiales o ecuatoriales. Same Length Chains Caption: The angle compression for butane is Newman Projection of Methylcyclohexane: When there are two carbon chains of the conformacions length, the one that has the most substituents must be chosen to name the compound.
conformaciones de butano
Conformations of Cyclohexane Caption: The methyl group is axial in one conformation, and equatorial in the other. Longer chained alkanes have greater surface area and can have more surface contact and more induced dipoles than branched alkanes with smaller surface areas.
Groups like tert-butyl are so bulky that it will force the chair conformation where it is in the equatorial position, regardless of other groups present.
The equatorial bonds are directed outward, toward the equator of the ring. Propane is shown here as a perspective drawing and as a Newman projection looking down one of the carbon-carbon bonds.
Estructura y Estereoquímica de Alcanos
The staggered conformations are lower in energy than the eclipsed conformation because the staggering allows the electron clouds of the C-H bonds to be as far apart zlcanos possible. The chair conformation of cyclohexane has one methylene group puckered upward and another puckered downward. Some common alkyl groups and their names. Butano tiene 2 conformaciones alternadas diferentes: Dr Analysis of Ethane Caption: Regardless of the other groups present, the most stable conformation has a t-butyl group in an equatorial position.
Some groups are so bulky that they are extremely hindered in axial positions. Chair-chair interconversion of methylcyclohexane.
Conformational Analysis of Butane Caption: Conformacuones interconversion would still produce an axial and an equatorial methyl. The only intermolecular force of nonpolar molecules are London dispersion forces which result from induced dipole attractions. Chair Conformations of cis-1,3-Dimethylcyclohexane Caption: This puckered conformation reduces the eclipsing of adjacent CH2 groups.
Estructura y Estereoquímica de Alcanos – ppt video online descargar
In this conformacines both chairs have the same energy, and they are present in equal amounts. The conformation of cyclopentane is slightly folded, like the shape of an envelope.
The four hydrogen atoms are covalently bonded to the central carbon atom, with bond lengths of 1.
The high reactivity of cyclopropanes is due to the non-linear overlap of the sp3 orbitals. Cyclic compound with 4 carbons or more adopt non-planar conformations to relieve ring strain.
Folding gives partial relief from the eclipsing of bonds, as shown in the Newman projection. The Newman projection is the best way to judge the stability of the different conformations of a molecule. In the actual molecule, the boat conformation is skewed to give the twist boat, a conformation with less eclipsing of bonds and less interference between the two flagpole hydrogens.
Ambas conformaciones tienen un metil axial y otro ecuatorial.
Análisis conformacional by Química Orgánica on Prezi
Angle strain in cyclopropane. Ethane, the two-carbon alkane, is composed of two methyl groups with overlapping sp3 hybrid orbitals forming a sigma bond between them. Among the staggered conformations, the anti is lower in alcxnos because it has the electron clouds of the methyl groups as far apart as possible.
Totally Eclipsed Conformation of Butane Caption: Comparison of the boiling points of the unbranched alkanes blue with those of some branched alkanes red.