Guest-Based Photoactive Porous Materials Based upon Zn-Carboxylate Metal Organic Frameworks

Metal organic framework (MOF) materials are attractive candidates for the development of solar energy applications due to the modularity of design, high porosity, and ease of functionalization of these materials. The encapsulation of photoactive guests into porous MOFs is a particularly attractive strategy for the development of photosensitive MOFs. This chapter is focused on the encapsulation of Ruthenium polyimine-type complexes into MOFs due to their high stability, robust photophysical properties, and excited state tuneability. It has now been demonstrated that Ru(II)tris(2,2⁰-bipyridine) (RuBpy) can exhibit a templating effect in the formation of the resultant metal organic framework (MOF) materials. A number of new topologies have now been synthesized using Zn(II) ions and carboxylate ligands in which the encapsulated RuBpy clusters exhibit unique photophysical properties. In this chapter, the relationship between MOF cavities and the RuBpy photophysical properties is reviewed. Two polyhedral MOFs (RuBpy@HKUST-1(Zn) and RuBpy@USF2) and five RuBpy templated MOFs (RWLC-1,-2,-3,-5 and-6) are discussed in terms of cavity influence on excited state population and decay pathways.