Question

Give some examples of molecules containing "fused" benzene rings.

Short answer

Some examples of molecules containing fused benzene rings include anthracene (\(C_{14}H_{10}\)) and phenanthrene (\(C_{14}H_{10}\)) with three fused benzene rings; naphthacene (\(C_{18}H_{12}\)) and pyrene (\(C_{16}H_{10}\)) with four fused benzene rings; and perylene (\(C_{20}H_{12}\)) and coronene (\(C_{24}H_{12}\)) with six fused benzene rings. These are all types of polycyclic aromatic hydrocarbons (PAHs).

Step-by-step solution

Step 1. Understanding Polycyclic Aromatic Hydrocarbons (PAHs)

Polycyclic aromatic hydrocarbons (PAHs) are compounds that consist of multiple aromatic rings, such as benzene rings, fused together. These compounds generally have three or more fused benzene rings. PAHs are mainly known for their carcinogenic and mutagenic properties, and they are often found in coal, tar deposits, and even in grilled food.

Step 2. Examples of molecules with three fused benzene rings:

- Anthracene (\(C_{14}H_{10}\)): In anthracene, there are three linearly fused benzene rings. It has the molecular formula \(C_{14}H_{10}\) and is a common PAH. - Phenanthrene (\(C_{14}H_{10}\)): Phenanthrene is another molecule with three fused benzene rings. However, its structure is slightly different from anthracene as its middle ring is fused to the other two rings in a non-linear fashion.

Step 3. Examples of molecules with four fused benzene rings:

- Naphthacene (\(C_{18}H_{12}\)): Naphthacene consists of four linearly fused benzene rings. It has the molecular formula \(C_{18}H_{12}\). - Pyrene (\(C_{16}H_{10}\)): Pyrene is another molecule with four fused benzene rings. Its structure consists of four benzene rings arranged in a square formation, with all the corner rings being fused to the central benzene ring.

Step 4. Examples of molecules with five fused benzene rings:

- Perylene (\(C_{20}H_{12}\)): Perylene consists of five fused benzene rings in a ladder-like structure. It has the molecular formula \(C_{20}H_{12}\). - Coronene (\(C_{24}H_{12}\)): Coronene is another molecule with six fused benzene rings, in which a central benzene ring is fused with six surrounding benzene rings, forming a hexagonal structure. It has the molecular formula \(C_{24}H_{12}\).