Staggered and eclipsed conformers In the staggered conformation, the
H atoms are as far apart as possible. This reduces repulsive forces
between them. This is why staggered conformers are stable. In the eclipsed
conformation, H atoms are closest together. This gives higher repulsive forces
between them. As a result, eclipsed conformers are unstable. At any
moment, more molecules will be in staggered form than any other
conformation.
Torsional energy and torsional strain Torsional energy is the energy
required for rotating about the C–C s bond. In ethane, this is very low (only
3 kcal). Torsional strain is the strain observed when a conformer rotates
away from the most stable conformation (i.e. the staggered form). Torsional
strain is due to the slight repulsion between electron clouds in the C–H
bonds as they pass close by each other in the eclipsed conformer. In ethane,
this is also low.
Conformational isomerism in propane Propane is a three-carbon- (sp3-
hybridized) atom-containing linear alkane. All are tetrahedrally arranged.
When a hydrogen atom of ethane is replaced by a methyl (CH3) group, we
have propane. There is rotation about two C–C s bonds.
Staggered and eclipsed conformers In the staggered conformation, theH atoms are as far apart as possible. This reduces repulsive forcesbetween them. This is why staggered conformers are stable. In the eclipsedconformation, H atoms are closest together. This gives higher repulsive forcesbetween them. As a result, eclipsed conformers are unstable. At anymoment, more molecules will be in staggered form than any otherconformation.Torsional energy and torsional strain Torsional energy is the energyrequired for rotating about the C–C s bond. In ethane, this is very low (only3 kcal). Torsional strain is the strain observed when a conformer rotatesaway from the most stable conformation (i.e. the staggered form). Torsionalstrain is due to the slight repulsion between electron clouds in the C–Hbonds as they pass close by each other in the eclipsed conformer. In ethane,this is also low.Conformational isomerism in propane Propane is a three-carbon- (sp3-hybridized) atom-containing linear alkane. All are tetrahedrally arranged.When a hydrogen atom of ethane is replaced by a methyl (CH3) group, wehave propane. There is rotation about two C–C s bonds.
การแปล กรุณารอสักครู่..
