Design of Novel Functional Materials Using Reactions of Quinones with Aromatic Amines

Abstract

This chapter presents examples for the successful use of Schiff base chemistry in the molecular design and synthesis of novel organic semiconductors composed of fused heterocyclic ladder oligomers as an alternative for oligoacenes. The materials resulting from reacting quinones with aryl amines (Schiff Bases) have proven to possess favorable properties for applications when compared with their oligoacene counterparts, including pentacene. Molecules obtained from reactions of 2,5- dichloro-1,4-benzoquinone and 2,3-dichloro-1,4-naphtoquinone with 2-aminophenols and 2-aminothiophenols discussed in this chapter. We also include one example of half a ladder molecule, which we usually use as a first step in the preparation of asymmetrical structures. Four molecules are discussed in this work. They are: benzo[5,6][1,4]thiazino[2,3-b]phenothiazine (1); 6,9-dichloro-5H-benzo[a]phenoxazin-5-one (2); benzo[a]benzo[5,6][1,4]thiazino [3,2-c]phenothiazine (3); and 13-nitrobenzo[a]benzo[5,6][1,4]oxazino[3,2-c]phenothiazine (4). Compounds 2 and 3 crystallize in the monoclinic space groups P21/c with four molecules in the unit cell each, whereas compound 4 crystallizes in the orthorhombic Fdd2 space group with 16 molecules in the unit cell. Some of the most significant features in the single-crystal structures of three of these are also discussed. π–π Stack distances of 3.085 and 3.290 Å were also observed in compounds 3 and 4.