Chapter 7 - Stereochemistry Chapter 7 Stereochemistry...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Stereochemistry Chapter 7 Stereochemistry • Stereochemistry refers to the three-dimensional structure of a molecule. • Minor differences in 3-D structure can result in vastly different properties.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Requires bacterial enzymes for digestion Digestible by most animals Why you eat corn but not the cob. ..but cows eat both. A particular three-dimensional arrangement is called a configuration . Stereoisomers differ in configuration.
Background image of page 2
Chirality • Although all objects have mirror images, the mirror images may or may not be superimposable . (superimposable = identical) Objects with “left-handed” and “right-handed” forms are said to be chiral . chiral – derived from the Greek word for hand ( cheir ) Stereochemistry • Other molecules or objects are indeed superimposable on their mirror image ( e.g. , socks). • A sock and its mirror image are identical. • A molecule or object that is superimposable on its mirror image is said to be achiral .
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chirality in Molecules Br Cl H F H Cl Br F To test for non-superimposability, rotate this model 180°around a vertical axis. Chirality in Molecules bromochlorofluoromethane
Background image of page 4
Br Cl H F H Cl Br F Chirality in Molecules bromochlorofluoromethane are enantiomers with respect to each other and Nonsuperimposable mirror images are enantiomers of each other. Chirality in Molecules Enantiomers
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
• A carbon atom with four different groups bonded to it is a tetrahedral chirality center . Chirality in Molecules Enantiomers No matter how you rotate the two molecules, the two will never completely overlap (superimpose). Ring carbons are chirality centers if two different groups are bonded to it and the path around the ring is different in each direction. • To find chirality centers , examine each tetrahedral carbon atom in a molecule, and look at the four groups—not the four atoms—bonded to it. All four groups must be different . Hints: Always omit from consideration CH 2 and CH 3 groups Any sp or sp 2 hybridized C chirality center
Background image of page 6
Chirality in Molecules Enantiomers • Generally a molecule with no chirality centers will not be chiral. • With one chirality center, a molecule will always be chiral. • With two or more stereogenic centers, a molecule may or may not be chiral. • Achiral molecules usually contain a plane of symmetry but chiral molecules do not. • A
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/22/2011 for the course CHEM 3371 taught by Professor Anderson,k during the Fall '08 term at Southern Methodist.

Page1 / 24

Chapter 7 - Stereochemistry Chapter 7 Stereochemistry...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online