On-Surface Supramolecular Chemistry with Porphyrins and Phthalocyanines: An Architectural Concept Leading to Engineered Quantum-Functional Nanostructures

摘要

The availability of porphyrin and phthalocyanine functionalization and synthesis, 'by design', at the time when sub-molecular resolution imaging at surfaces came into action boosted the emergence of 'On-Surface-Supramolecular Chemistry'. It is instructive to compare supra-molecular binding motifs in the fluid phase with the corresponding or modified analogues found after assembly on surfaces. In some similarity to chemistry and coordination chemistry translating into the corresponding 'on-surface' sciences, there are many factors complicating the on-surface assembly and architecture. Examples are provided by the modified dimensionality and kinetics, the site-specific conformational flexure and chirality and the close to irreversible adsorption in the strong surface potential in absence of a solvent which may complicate the on-surface assembly and architecture. Further, porphyrins and phthalocyanines interact with the substrate by different, competitive interactions, i.e. via (1) the central metal atom and (2) the porphyrin pi-system in addition to (3) the functional side groups. Binary and ternary assemblies of porphyrins and other functional components make it possible to create a wealth of 'phases', i.e. different complex supramolecular architectures with interesting physical properties to explore and exploit.