Functionalization of Semiconductor Surfaces

CHAPTER 6

Influence of Functional Groups in Substituted Aromatic Molecules on the Selection of Reaction Channel in Semiconductor Surface Functionalization

ANDREW V. TEPLYAKOV

6.1 INTRODUCTION

6.1.1 Scope of this Chapter

Aromaticity has long been a fascinating topic in the entire field of chemistry [1]. Since the discovery of benzene that in a few years will celebrate its bicentennial anniversary, scientists and engineers have put this concept to a good use. As the measurements and applications have evolved though, the definition of aromaticity has also undergone dramatic changes. The original formulations of Kekulé (1865) and Erlenmeyer (1866) have become much more general and are based mostly on experimental and computational observations of the exceptional stability of aromatic compounds. The unusually high degree of symmetry of their molecular and often crystal structures and, as a consequence, often a highly symmetric wave function describing their quantum mechanical behavior lead to unusual magnetic and spectroscopic characteristics of aromatic compounds. It should be pointed out that the initially accepted description of aromaticity as a characteristic of compounds whose molecules are built upon flat ring-like structures with 4n+2 π electrons has long been abandoned as the aromaticity in some species has been demonstrated to involve σ orbitals, or only 4n electrons instead of 4n+2, or even be observed in transition metal sandwich structures and in three-dimensional clusters. ...