1、Yuxin Pei (裴玉新) 2012-10-23,Organic Stereochemistry,Contents,Introduction Stereoisomerism and Chirality Properties - has optical activity (the property of rotating the plane of plane-polarized light).,1.4 Polarimetry and Optical Rotation,optical activity,1.4 Polarimetry and Optical Rotation,optical a

2、ctivity,1.4 Polarimetry and Optical Rotation,Polarimeter,1.4 Polarimetry and Optical Rotation,Sample: liquid (neat, density) solution (solvent, concentration) solid/gas, : Observed rotation,dextrorotatory (+) or (d) do not confuse with D Counter-clockwise direction levorotatory (-) or (l) do not con

3、fuse with L,when the plane of polarized light is rotated in a,Clockwise direction,1.4 Polarimetry and Optical Rotation,specific rotation (D = sodium lamp, = 589 nm). Dimension of : deg.cm2.g-1 = +6.2 (c 1.0, EtOH),c： Concentration（g/100mL） l： Length （dm）,: Observed rotation,1.4 Polarimetry and Optic

4、al Rotation,Limitation: max unknown in most cases, questions regarding reliability of the published data. 2. The smaller the optical rotation, the bigger the error. 3. Nonlinear affected by concentration, temperature, impurity, solvent and etc. 4. Large amount of sample needed.,1.4 Polarimetry and O

5、ptical Rotation,1.4 Polarimetry and Optical Rotation,Problem: Please explain the meaning of the following description:,= -20.6 (c 1.3, CHCl3),Chapter 1 Homework,Explain briefly the meaning of the following basic stereochemical terms. Stereochemistry Chirality Plane-polarized light Polarimeter Optical activity Observed optical rotation Specific rotation What is the units of observed optical rotation and specific rotation? Design an experiment for measuring the s