Conformer

A conformer is a molecule that has the same chemical formula and bonding arrangement as another molecule (an isomer), but differs in the three-dimensional shape due to rotation around a single bond. Conformers, unlike structural isomers or stereoisomers, are generally rapidly interconvertible at room temperature. The energy difference between different conformers, referred to as conformational isomers, arises from the steric hindrance (repulsion between atoms), and electronic effects within the molecule. The preference for one conformer over another is determined by the stability and energy levels of the molecule, often influenced by factors like temperature, solvent, and the presence of other molecules. The study of conformers is crucial in understanding a molecule's reactivity, physical properties, and its interactions with other molecules, especially in biochemistry, where the shape of a molecule is critical to its function.

Conformer meaning with examples

• The rotation around the C-C bond in ethane results in different conformers, namely staggered and eclipsed forms. The staggered conformer is more stable, having lower potential energy due to the minimized steric repulsion between the hydrogen atoms, and is therefore favored at room temperature. The study of conformers provides a method for understanding the physical properties and how these are determined by the shape of the molecule.
• Cyclohexane exhibits several conformers. The most stable is the chair conformer, where the atoms are staggered, and the hydrogen atoms are relatively far apart. A less stable form is the boat conformer, that is more strained due to the eclipsed interactions. The existence of these conformers explains cyclohexane's inertness at room temperature, and ability to react under increased temperatures.
• In the context of protein structure, different conformers of a polypeptide chain give rise to distinct secondary structures, like alpha helices and beta sheets. The flexibility of the polypeptide backbone allows it to explore various conformational spaces, adopting forms that allow specific folding, determined by hydrogen bonds. Conformers have a profound effect on the interactions of these molecules.
• Understanding the conformers of drug molecules is essential in drug design, since it impacts the molecule's ability to bind to its target protein. A drug molecule may only bind effectively in a specific conformation, therefore, predicting and designing this conformation is crucial. By determining these conformers scientists can produce more effective and less damaging drugs to our health.
• Computational chemistry methods are frequently used to simulate and predict the different conformers a molecule might adopt, and their relative stabilities. Molecular dynamics simulations can track how molecules convert through many conformations over time. These computations helps scientists to understand the behavior of large, complex molecules, and provides a greater insight into the properties of said molecules.