Streochemistry
Experiment 1
Stereochemistry
Stereochemistry is the study of the three-dimensional configuration that makes up a molecule and the ways in which this arrangement affects the physical and chemical properties of molecules. Isomerism is the main concern of stereochemistry. Isomers are sets of chemical compounds with identical molecular formulas but different structural properties. There are two types of isomers, structural isomers and stereoisomers.
Structural isomers are subdivided into two: position and functional isomers. Position isomers occur among substituted hydrocarbons. The substituents are attached to different positions on the carbon chain.
ex. CH3CH2CH2OH CH3CH(OH)CH3 1-propanol 2-propanol
Functional isomers, on the other hand, have very different chemical properties because differences in the structures give rise to different functional groups. ex. CH3CH2OH CH3OCH3 ethanol dimethyl ether
Stereoisomers are molecules which have the same basic arrangement of atoms in their molecules but differ in the way the atoms are arranged in space. There are three basic types of stereoisomers such as conformational isomers, geometric isomers and optical isomers. Molecules that exhibit free rotation about a single bond give rise to conformational isomerism. This is usually illustrated by alkanes due to their C-C single bond. It is usually represented using the Newman projection.
eclipsed staggered
anti-staggered gauche-staggered
chair boat
The second type of stereoisomerism is geometric isomerism which is common in alkenes. Geometric isomers differ in physical properties such as melting points and boiling points.
ex. cis (same side) trans (opposite side)
For alkenes where cis-trans configuration does not apply, the geometry of the alkene may be designated by E (entgegen, opposite) or Z (zussamen, together). This is applied by determining
Stereochemistry
Stereochemistry is the study of the three-dimensional configuration that makes up a molecule and the ways in which this arrangement affects the physical and chemical properties of molecules. Isomerism is the main concern of stereochemistry. Isomers are sets of chemical compounds with identical molecular formulas but different structural properties. There are two types of isomers, structural isomers and stereoisomers.
Structural isomers are subdivided into two: position and functional isomers. Position isomers occur among substituted hydrocarbons. The substituents are attached to different positions on the carbon chain.
ex. CH3CH2CH2OH CH3CH(OH)CH3 1-propanol 2-propanol
Functional isomers, on the other hand, have very different chemical properties because differences in the structures give rise to different functional groups. ex. CH3CH2OH CH3OCH3 ethanol dimethyl ether
Stereoisomers are molecules which have the same basic arrangement of atoms in their molecules but differ in the way the atoms are arranged in space. There are three basic types of stereoisomers such as conformational isomers, geometric isomers and optical isomers. Molecules that exhibit free rotation about a single bond give rise to conformational isomerism. This is usually illustrated by alkanes due to their C-C single bond. It is usually represented using the Newman projection.
eclipsed staggered
anti-staggered gauche-staggered
chair boat
The second type of stereoisomerism is geometric isomerism which is common in alkenes. Geometric isomers differ in physical properties such as melting points and boiling points.
ex. cis (same side) trans (opposite side)
For alkenes where cis-trans configuration does not apply, the geometry of the alkene may be designated by E (entgegen, opposite) or Z (zussamen, together). This is applied by determining
References: Institute of Chemistry. “Organic Chemistry Laboratory Manual” UP Diliman, 2004 Institute of Chemistry. “Laboratory Manual in Basic Organic Chemistry” UP Los Baños. Palleros, D.R. “Experimental Organic Chemistry” N.Y. John Wiley & Sons, Inc. 2000.