Do you know what is celebrated on June 21?
Make a hunch. You've probably seen people pose in various body-contorting positions.
Yes! The 21st of June is recognized as International Yoga Day!
The advantages of yoga for physical and mental health care are available to people of all ages. If you are recovering from surgery, fighting an illness, or managing a chronic condition, yoga can also play a significant role in your care and possibly hasten your recovery. Tadasana (Mountain Pose), Utkatasana (Chair Pose), and Virabhadrasana (Warrior Pose), to mention a few, are a handful of the many yoga poses.
You may have noticed that shifting your body position can be done in a variety of ways. Alternately, we could assert that there are countless possible spatial configurations. Similarly in chemistry, by rotating the single bonds, a molecule can take on a number of shapes while maintaining its localised atom arrangement (every saturated carbon atom is tetrahedral).
Let us study more related to the different conformations of butane and their stability in detail on this concept page.
TABLE OF CONTENTS
In alkanes, the electron distribution in the sigma molecular orbital is symmetrical around the C-C bond's internuclear axis. As a result, unfettered rotation around the C-C single bond (sigma bond) is possible. Different spatial arrangements of carbon atoms in space are observed as a result of this rotation, which can transform into one another.
Conformation, conformer, or rotamer refers to a spatial configuration of different groups (substituents) transformed into one another by rotating around a C-C sigma bond.
Rotation around C-C single bonds allows alkanes to have an endless variety of conformations. However, due to repulsive interactions between the electron clouds of C-C bonds, this rotation is not totally free. Torsional strain and van der Waals strain are the names for this repulsive relationship.
There are a few terms related to conformational analysis. These are explained below.
a.) Free Rotation
A sigma covalent bond which undergoes free rotation at room temperature such as
b.) Conformers / Rotamers or Conformations
Due to free rotation along a sigma covalent bond, molecules can have an endless variety of spatial orientations which are referred to as conformers.
c.) Conformational Isomers
The formula of butane can be represented as given below.
Butane is a type of alkane that has C-C bonds. When we rotate the butane molecule around the axis of the C2-C3 bond, it normally exhibits distinct conformational isomerism. Fully eclipsed, gauche, eclipsed, and anti are the four conformational isomers of Butane.
Let's have a look at these isomers in more detail.
The stability order of the conformations of butane is listed below from the lowest to the highest. The conformer with the most energy is the least stable, whereas those with the least energy are the most stable.
The order of stability of conformers of butane is Anti > Gauche > Partially eclipsed > Fully eclipsed.
Let's take a moment to imagine what the energy–rotation graph might look like before we start drawing it.
Q1. Different configurations of atoms can be changed into one another by rotating around the __________.
A. Double bond
B. Single bond
C. Triple bond
D. Rotation is not possible
Solution: Conformational isomerism is a type of stereoisomerism in which isomers can only be interconverted by rotating them around formally single bonds. Conformational isomers, also known as conformers or conformers, or rotamers, are examples of such isomers.
So, option B) is the correct answer.
Q2. __________ is the amount of energy required to rotate an n-butane molecule around its carbon-carbon bond.
A. Enantiomeric energy
B. Potential energy
C. Rotational energy
D. Conformational energy
Solution: Conformational energy is the amount of energy required to rotate a molecule around a carbon-carbon bond.
So, option D) is the correct answer..
Q3. The energy required to rotate n-butane around the (C2-C3) carbon-carbon bond is about _______.
A. 3 kJ mol-1
B. 10 kJ mol-1
C. 50 kJ mol-1
D. 100 kJ mol-1
Solution: The rotation of n-butane around the (C2-C3) carbon-carbon bond requires only about 3 kJ mol-1of energy.
So, option A) is the correct answer.
Q4. Due to _______________, gauche conformation is less stable than eclipsed conformation in n-butane.
A. Angle strain
B. Hydrogen bonding
C. van der Waals repulsion
D. Covalent bonding
Solution: As van der Waals’ force of attraction is weak, gauche conformation is less stable than eclipsed conformation of n-butane.
So, option C) is the correct answer.
Q1. Is it possible to separate conformers?
Answer: Yes, it is possible to separate conformers. Atropisomers, for example, are conformational isomers that can be differentiated due to constrained rotation. Atropisomers are conformers in which steric hindrance severely restricts the rotation around a single bond. These conformers can be isolated as a result.
Q2. What exactly does it mean to be superimposable?
Answer: Superimposable (superposable) is the ability to place one thing on top of another, usually so that both are visible. The ability for an object to be positioned over another object is frequently interchanged with the broader term superimposable, which implies that visibility is not limited.
Q3. What do you understand by the term ‘Newman projection’?
Answer: A Newman projection depicts the conformation of a chemical bond from front to back, with a line representing the front atom and a circle indicating the back carbon. It is useful in alkane stereochemistry. The atom closest to the front is referred to as proximal, whereas the atom closest to the back is referred to as distal.
Q4. What do you understand by the term ‘Sawhorse projection’?
Answer: A sawhorse projection depicts the conformation of a molecule at an angle rather than straight on. A figure known as a saw-horse formula is used to show a particular molecule's conformation. The sawhorse projection makes the three-dimensional geometry between neighbouring carbon atoms easier to see. This projection is typically used to illustrate interactions in processes between groups on nearby carbon atoms.