The realization of molecular nanodevices with advanced functions requires the development of new approaches to construct desired molecular nanostructures. Supramolecular approach starting from molecular building blocks can lead to controlled structures, which is achieved by selective and directional intermolecular interactions. When noncovalent intermolecular interactions, such as hydrogen bonding, are introduced into functional molecules, the selective intermolecular interaction results in the controlled formation of molecular nanostructures yielding exclusive crystals or dissolved structures. To adapt the functional supramolecular structures to nanodevices, it is necessary for the supramolecular structures to be supported on suitable substrates and at suitable positions. Although these surface-supported supramolecular structures have been directly observed using scanning tunneling microscopy (STM), the further control of their size and shape on surfaces should become a next step for realizing molecular nanodevices. This chapter demonstrates selective assembly of supramolecular aggregates with controlled size and shape on a gold surface by modifying substituent structures. The controlled aggregation of porphyrins has succeeded on a gold surface, which was visualized by low-temperature STM. On this surface, monomer, trimer, tetramer, or wire-like arrangements were controlled by local substituent interactions, and these structures were spontaneously and selectively formed by changing substituents. The selective aggregation approach should become a general strategy for the rational design and construction of desired molecular architectures on substrate surfaces.
|Title of host publication
|Nanotechnology and Nano-Interface Controlled Electronic Devices
|Number of pages
|Published - Apr 2003
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy