Yes, if one part of a molecule is antiaromatic, it can make the whole structure antiaromatic. A molecule is considered antiaromatic if it possesses a cyclic, conjugated system of π electrons with a continuous overlap of p-orbitals and follows the 4n Rule, where n is an integer. According to the 4n Rule, a molecule is antiaromatic if the number of π electrons is equal to 4 (4n) where n is an integer. Therefore, if even one part of a molecule fulfills the criteria for antiaromaticity, the entire structure would be considered antiaromatic.
