Ferrocene is a sandwich-like compound composed of two cyclopentadienyl anions (C5H5–) that are bonded to a central iron (Fe2+) atom. The structure is rotationally symmetrical, and the electronic distribution is relatively uniform across the entire molecule, resulting in a non-polar character.
On the other hand, acetylferrocene is a derivative of ferrocene where an acetyl group (C2H3O) has been introduced to one of the cyclopentadienyl rings. This substitution introduces a polar carbonyl group (C=O) into the structure of ferrocene, which can significantly affect its overall polarity.
Due to the presence of the polar acetyl group in acetylferrocene, it disrupts the otherwise symmetrical charge distribution in ferrocene. The electronegativity difference between the carbon and oxygen in the carbonyl results in a dipole moment that points towards the oxygen. Therefore, while ferrocene is largely non-polar, acetylferrocene is expected to exhibit greater polarity due to the influence of the acetyl group.
In conclusion, acetylferrocene is more polar than ferrocene because the introduction of the acetyl group introduces a significant polar feature, which is absent in the structurally symmetrical ferrocene. Hence, we can predict that acetylferrocene will have stronger interactions with polar solvents compared to ferrocene.