Levorotatory compound

Most of the physical properties (e.g., boiling and melting point, density, refractive index, etc.) of two enantiomers are identical. Importantly, however, the two enantiomers interact differently with polarized light. When plane polarized light interacts with a sample of chiral molecules, there is a measurable net rotation of the plane of polarization. Such molecules are said to be optically active. If the chiral compound causes the plane of polarization to rotate in a clockwise (positive) direction as viewed by an observer facing the beam, the compound is said to be dextrorotatory. An anticlockwise (negative) rotation is caused by a levorotatory compound. Dextrorotatory chiral compounds are often given the label d or ( + ) while levorotatory compounds are denoted by l or (—). 

CAS 137-32-6. CH3CH2CH(CH3)CH2OH. The active alcohol from fusel oil. The synthetic product is a racemic mixture of both dextro- and levorotatory compounds and therefore not optically active. 

Quinine is the main alkaloid obtained from the bark of the cinchona tree (Cinchona officinalis, and other hybrids). It is a levorotatory compound (its dextrorotatory diastereoisomer quinidine, obtained from the same source, is used primarily as a cardiac antiarrhythmic, Chapter 10). The cinchona trees cultivated on the island of Java, Indonesia, have the highest total alkaloidal content in its bark, 7-10%. About two-thirds of this total is quinine. The other significant alkaloids are quinidine, the diastereoisomeric pair cincho-... 

In reporting either observed or specific rotation, it is common to indicate a dextrorotatory compound with a plus sign in parentheses, (-f), and a levorotatory compound with a minus sign in parentheses, (—). For any pair of enantiomers, one enantiomer is dextrorotatory and the other is levorotatory. For each member, the value of the specific rotation is exactly the same, but the sign is opposite. Following are the specific rotations of the enantiomers of 2-butanol at 25 °C, observed with the D line of sodium ... 

An optically active substance that Is dextrorotatory would rotate plane-polarized light to the right (clockwise), while a levorotatory compound would rotate plane-polarized light to the left (counterclockwise). 

Explain the important distinction between each of the following pairs (a) coordination number and oxidation number (b) monodentate and polydentate ligands (c) cis and trans isomers (d) dextrorotatory and levorotatory compounds (e) low-spin and high-spin complexes. 

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