CONFORMATIONAL ISOMERISM Meaning and
Definition
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Conformational isomerism refers to a specific type of isomerism observed in molecules, wherein the spatial arrangement of atoms in the molecule can be altered by rotation around single bonds. This type of isomerism arises due to the flexibility of the carbon-carbon, carbon-nitrogen, or carbon-oxygen single bonds involved in the molecule.
In conformational isomerism, the structural integrity of the molecule remains unchanged, but different conformations or arrangements of the molecule can be attained by rotation around these bonds. The conformations arise from the torsional rotation of the bonds, resulting in different orientations of the atoms in space.
The different conformations, also known as conformers or rotamers, represent energetically distinct spatial arrangements of the molecule. These conformers can be interconverted by overcoming the energy barrier associated with bond rotation. They exhibit different stabilities due to the varying interatomic interactions, such as steric hindrance and van der Waals forces, which influence their overall energy levels.
The conformational isomers do not possess separate chemical properties but can influence the physical properties of the molecule, such as boiling point, dipole moment, and solubility. The energy differences between the different conformations are relatively small, and the interconversion between them occurs rapidly at room temperature.
Understanding conformational isomerism is crucial in fields such as organic chemistry and drug design, as it allows for the elucidation of molecular structures and the prediction of stability and reactivity.
Etymology of CONFORMATIONAL ISOMERISM
The word "conformational isomerism" is composed of two main components: "conformational" and "isomerism".
1. "Conformational" derives from the noun "conformation", which originated from the Latin word "conformare", meaning "to shape or mold together.”
2. "Isomerism" comes from the Greek terms "isos", meaning "equal", and "meros", meaning "part".
When combined, "conformational isomerism" refers to the phenomenon in chemistry where molecules have the same atomic composition but differ in spatial arrangement due to rotation around single bonds. The term was likely coined in the field of organic chemistry to describe this specific type of isomerism.
