Conformational Isomerism

University:
Boston University
Course:
GRS CH 644 | Medicinal Chemistry
Academic year:

2023
Views:

390

Pages:

4
Author:

StellarSymphony

Conformational Isomerism :- Different spatial arrangement of atoms on greaups Cau be that Converted into one another by the rotation around Single bond are called Conformere or Conformation on Conformational isomers. This phenomenon is called. Isomerism. as Conformat Characteristics:- 1. The Various Conformen of the same Compound are Slight! differ in their energy Content. 2. The energy of the arrangement is maximum when the bond Pair of two central Carbon atom are vere to each other. Such an arrangement Verry Closed is Called eclipsed form This is the most unstable Conformation of as the energy is maximum or highest. 3. The energy of the arrangement is minimum when the bond Pair of two Central Carbon atom are far apart from each other. Such au arrangement is Called Staggered form This is the most Itable Conformation as the energy is minimum or lowest. 4. A lange no. of Conformation involve in Carbon-Carbon bond may be Possible depending up on angle of rotation. All the conformation other than eclipsed and staggered arce Called as Skew or Gauche form. 5. The energy difference between any two Conformation is not more than 5 kcal/mol. Conformation of Ethane:- (H) In this molecule, two (arborn atom are bonded by a single bond. Therefure, ethane is capable of showing Conformational isomerism. Due to free rotation of one Carbon atom win.t.. the other, a numberrous Conforamen are Possible. In this molecule, two Pirominent conformer will be Possible those are- i) In One form. C-H bonds of two Carbon atom are Veng closed to each other (Eclipsed funm). 1) In Othen forem, the C-H bonds are far apart from each other. (Staggered form) The Various Conforamation of ethane Can be represented where one of the Carbon atom to be fixed and the other One is rotated through an angle of 60°. The notation is Carried out by using Newmans Projection formula as below :- Energy Profile diagram of ethane Cau be represented as 12.67/mal Augle of rotation 1. The Staggered forem is more stable forem. In this forme, bond pair of all the C-H bond are far away from each other. The energy repulsion between C-H bond Pair. is minimum because of less 2 The eclipsed form is most unstable form. In this form. bond Pair of all the C-H bond very closed to each are ver other. The energy is maximum because of mom between C-H bond fair. repulsom 3 The energy difference between these two form is about 12.6 kJ/md