This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ge and mirror image are superimposable: Achiral. Quick test: Chiral molecules lack a mirror plane. Asymmetric Carbon: No Mirror Plane cis-trans Cycloalkanes are "diastereomers" Objects are Chiral and Achiral Escargot 20,000 : 1 Enantiomers: Which is which? Absolute Stereoisomerism configuration. 1. X-ray crystal structure. "Photo." 2. Polarimeter: Optical rotation of plane polarized light: Image dextrorotatory (clockwise), (+)-enantiomer Mirror image levorotatory (counterclockwise), (-)-enantiomer. The Polarimeter Enantiomers are optically active. Racemates are not. Measured rotation t(C) = Optical rotation: lc
D CH2CH3 CH2CH3 H Br H Br * C CH3 H3C +23.1
Mirror plane C* Length of vessel (in dm usually) Concentration (g ml-1) -23.1 is called specific rotation. Note: Sign of rotation does not tell...
View Full Document
- Fall '04