PAHs with Five-membered Rings

PAHs with Five-membered Rings 13.4.2.1 Corannulene 

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Polycyclic aromatic hydrocarbons (PAH s) with external cyclopentafused five-membered rings, such as the cyclopentafused pyrene derivatives (Fig. 10), belong to the class of non-alternant polycyclic aromatic hydrocarbons. 

Compound 45 is nonplanar, based on molecular model calculations, due to the presence of five-membered rings, and therefore offers the possibility to create bowl-shaped molecules via flash vacuum pyrolysis (FVP) [86, 89]. The C150 disc 47 is the largest disc with threefold symmetry yet made [86], whereas the giant nanographene 48 with its 222 carbon atoms is the largest PAH to be synthesized and characterized to date [88]. 

The fusion of four-, five-, or six-membered rings with benzenoid rings usually produces nonalternant PAHs, examples of which are shown in Fig. 3.6 [10]. 

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