The structure of cyanidin is as follows:
There are eight double bonds in the entire compound, and hence $8 \times 2 = 16$ π-electrons, which does not satisfy the $4n + 2$ rule. However, the molecule is usually depicted as aromatic in literature. MarvinSketch (a software) also reports the entire molecule as aromatic.
- Is this molecule aromatic? Why?
- Are all anthocyaninidins aromatic?