Abstract

An exploration of the 2D supramolecular self-assembly of benzoquinone derivatives at the liquid-solid interface using scanning tunneling microscopy (STM) is presented. In the 30 years since its discovery, STM has emerged as one of the most powerful and unique surface characterization techniques. We have applied a versatile transamination reaction of 2,4-diaminoresorcinol to synthesize zwitterionic meta-diaminobenzoquinones (Cnm) with the ability to form robust charge-assisted hydrogen bonded arrays. Charge-assisted hydrogen bonding, where traditional hydrogen bonding is accompanied by Coulombic interactions, leads to exceptionally strong and inherently flexible interactions between oppositely charged or zwitterionic components. The typical energy of a NH···O charge-assisted hydrogen bond is 4 times as strong as that of normal hydrogen bond. We also have easy access to para-aminobenzoquinones (Cnp) which have the ability to form a conventional hydrogen-bond network. Formation and self-assembly of the 2:1 metal complex of C18m with Ni(II), (C18m)2Ni, was investigated and conglomerate chiral domains were observed in contrast to the pseudoracemic domains of C18m. In this thesis, synthesis of the above mentioned compounds under both solvent and solvent-free conditions are described. In addition, factors governing morphology, chirality and multilayer formation are discussed, presenting an important foundation for understanding the properties of a large family of related molecules with interesting potential in supramolecular design. Controlling well-defined 2D structures provides important insight into crystallization and is an essential step in the rational design of solid-state materials for interfacial applications.