Photophysical Studies of MOF Encapsulated Ruthenium Polyimines for Light Activated Drug Delivery

Michaela Senn, Randy Larsen

University of South Florida

The ability to confine photo-active transition metal complexes within metal-organic frameworks (MOFs) provides a platform for a wide range of applications including photocatalysis, light harvesting and light responsive drug release. Here, ruthenium polyimine complexes including Ru(II)(2,2’-bipyridine) (RuBpy), Ru(II)bis(2,2’-bipyridine)(6,6’-dimethyl-2,2’-bipyridine) (RuBpy₂Dmbpy), and Ru(II)(2,2’-bipyridine)(2,2’:6,2’’-terpyridine)(L) (RuTrpyBpyL) where L = acetonitrile, are investigated as photo-active guests encapsulated within the cavities of polyhedral Zn²⁺ based MOF USF-2 and Cd²⁺  based MOF RWLC-5. By varying the ancillary ligands of the ruthenium polyimine complex and the MOFs topology, ligand photo-release quantum yields can be modulated, as the energy barrier between the ³MLCT and ³LF states of the ruthenium polyimine can be modulated by the nature of the MOFs cavities.