ISOMERIA CONFORMACIONAL PDF
Isomeria Conformacional. fhmateo; 3 videos; 18 views; Last updated on Oct 11, Play all. Share. Loading Save. Empleo de la notación E-Z en la isomería Cis-Trans | | UPV – Duration: Universitat. Isomería de conformacional de alcanos y ciclo alcanos. Isomería conformacional (cis-trans): en dobles enlaces, en anillo.
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Conformations of Cyclobutane Caption: Among the staggered conformations, the anti is lower in energy because it has the electron clouds of the methyl groups as far apart as possible.
Structures of some cycloalkanes. Conformational Analysis of Ethane Caption: El Cis-1,3-dimetilciclohexano puede tener ambos grupos axiales o ecuatoriales. Viewed from the Newman projection, the chair conformation has no eclipsing of the carbon-carbon bonds. Rotations about the center bond in butane give different molecular shapes. Pure conformers cannot be isolated in most cases, because the molecules are conforacional rotating through all the possible conformations.
Melting Points of Alkanes Caption: Conformational energy of cyclohexane. The other eclipsed conformations are lower in energy than the totally eclipsed conformation but are still more unstable than the staggered conformations. Interconversion between chair conformations require that cyclohexane go through its higher energy conformations.
Conformations of Ethane Caption: Chair interconversion would still produce an axial and an conformcaional methyl. Two chair conformations are possible for cis-1,3-dimethylcyclohexane. The chair conformation is most stable, followed by the twist boat. Alkyl substituents on cyclohexane rings will tend to be equatorial to avoid 1,3-diaxial interactions.
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 as possible. Esta interferencia es llamada interacciones 1,3-diaxial. The Newman Projection of Propane Caption: This kind of interference between two bulky groups is called steric strain or steric hindrance. The ring strain of a planar cyclobutane results from two factors: In the actual molecule, the boat conformation is skewed to give the twist boat, a conformation with less eclipsing of bonds and less interference conformcaional the two flagpole hydrogens.
Chair Conformations of trans-1,3-Dimethylcyclohexane Caption: In the Newman projection it is easier to see the steric interaction between the methyl substituent and the hydrogens and carbons of the ring.
Estructura y Estereoquímica de Alcanos
Conformations of Cyclopropane Caption: Cyclic compound with 4 carbons or more adopt non-planar conformations to relieve ring strain. The melting point curve for n-alkanes with even numbers of carbon atoms is slightly higher than that for alkanes with odd numbers of carbons.
Newman Projections of Butane Caption: There is steric hindrance between these hydrogens so the molecule twists a little producing the twist boat conformation which is 1. At room temperature, this barrier is easily overcome, and the molecules rotate constantly. Conformational Analysis of Butane Caption: The axial substituent interferes with the axial hydrogens on C3 and C5. Solution The longest carbon chain contains eight carbon atoms, so this compound is named as an octane.
In this case both chairs have the same energy, and they are present in equal amounts.
The even-numbered carbons have their downward bonds axial and their upward bonds equatorial. The six-membered rings in cis- and trans-decalin assume chair conformations. The C-C bond distance is 1. The chair conformation of cyclohexane has one methylene group puckered upward and another puckered downward.
Isomerisme conformacional – Viquipèdia, l’enciclopèdia lliure
The angle compression for butane is The following figure shows the severe steric interactions in a chair conformation with a t-butyl group axial. The conformation of cyclopentane is slightly folded, like the shape of an envelope.