CH 221 1st Edition Lecture 11Outline of Last Lecture I. Quarternary Ammonium SaltsII. Staggered and Eclipsed StructuresIII. Zig Zag Arrangement IV. Bond Angles in Planar Cyclic AlkanesOutline of Current Lecture V. Isomersa. Cis-Trans IsomersVI. Chiral and AchiralVII. EnantiomersCurrent LectureV. Isomers- compounds that have the same formulas but with different structures- Constitutional isomers differ in the ways atoms are connected such as ethanol, dimethyl ether, acetone, propionaldehyde, 1-chlorobutane, and 2-chlorobutanea. Cis-Trans isomers have a doubled bonded restricted rotation- Cis- hydrogens are on the same side of the double bond- Trans- hydrogens are on opposite sides of the double bond- They have different physical/biological properties such as boiling point and polarity- Some alkanes don’t have cis-trans isomers because two substituents on ansp2 carbon are the same- Cis-Trans isomers have different configurationsCompounds with different conformations cannot be separated and compounds with different configurations can be separated.VI. Chiral objects- mirror image is different than the original- Achiral objects- mirror image is the same as original - An asymmetric center is an atom that is attached to four different groups such as in 4-bromobutane, 4-octanol, and 2,4-dimethylhexaneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.VII. Enantiomers- two isomers that are different compounds, can be separated, and have the same physical and chemical properties- Enantiomers are nonsuperimposable mirror images- Naming enantiomers begins by assigning relative priorities to the four groups based on Cahn-Ingold-Prelog rules- Example: for 2-bromobutane, begin by numbering Br with 1 because it has the highest atomic number- Hydrogen has the lowest atomic number, therefore it gets numbered 4- After numbering the components, draw an arrow from 1 to 2 to 3- The group with the lowest priority, in this case hydrogen, is bonded by a hatched wedge- If the lowest priority group is on a hatched wedge then clockwise arrows=R and counterclockwise
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