Torsionsbarriere

Torsionsbarriere refers to the energy required to rotate a bond between two atoms within a molecule. This rotational barrier arises from the overlap of electron clouds around the bond and steric interactions between atoms or groups attached to the rotating atoms. Different conformations of a molecule are separated by these energy barriers, and rotation around a single bond is typically not completely free but rather involves overcoming a small energetic hurdle.

The magnitude of the torsionsbarriere depends on several factors, including the type of bond (single, double, or triple), the nature of the substituents on the bonded atoms, and the electronic environment of the molecule. For instance, rotation around a double bond is significantly hindered due to the strong pi-bond component, leading to a high torsionsbarriere and the existence of cis and trans isomers. Rotation around single bonds is generally easier, with lower energy barriers, allowing for greater conformational flexibility. Understanding torsionsbarriere is crucial in various fields, including organic chemistry, biochemistry, and materials science, as it influences molecular shape, reactivity, and physical properties. Computational methods are often employed to calculate and predict these energy barriers.