Multinuclear Metal Complexes: Coordination Dendrimers, Polymers, and Coordination Cages

Supramolecular multinuclear systems with well-defined structures and architectures capable of responding to external stimuli such as photons or electrons have become increasingly interesting and are fundamental objectives for the design of future functional devices at the nanoscale. Metal-containing macromolecules as coordination dendrimers, polymers, and cages have become a field of huge and wide interest because of their possible application in a number of fields ranging from solar energy conversion and optoelectronics to bioimaging and drug delivery. The presence of transition metal ions in a supramolecular structure would offer an attractive platform for combining the chemical, electronic, and optical properties of metal complexes with those of the organic materials. In recent decades, many efforts have been devoted to the development of efficient and effective synthetic protocols for the preparation of these multi-nuclear structures with specific functions. In this chapter we would like to resume the principal research output of the field, essentially related to the facile tuning of photophysical properties and photo-activated functions of these versatile materials. To this goal we have tried to underlie the relationship between chemical and electronic structures of these species and their photophysical properties. Because of their intriguing properties the literature is very extended, and then it is clear that is not possible to prepare a review which can be comprehensive on photoactive supramolecular multimetallic compounds, so this chapter must be limited in its scope and will deal with a few examples of coordination dendrimersDendrimers, polymers, and cages.