Metal-organic framework host/guest photocatalysts for CO₂ reduction

Jessica N. Martin and Randy W. Larsen

University of South Florida

Currently, fossil fuels including coal, petroleum and natural gas, account for over 80% of worldwide energy usage. Combustion products from these energy systems make a significant contribution to greenhouse gases and represent a significant environmental threat. To mitigate the threat of greenhouse gas emission, catalysts capable of both capturing and reducing greenhouse gases, such as CO₂, are of critical importance. A particularly attractive class of CO₂ photoreduction catalyst involve Re(I)(CO)₃(2,2’-bipyridine)L complexes where L represents a photoreleasable ligand. Coupling this type of catalyst with a porous metal-organic framework (MOF), capable of sequestering high concentrations of CO_2, represents a significant advance in technology for CO₂ mitigation. Here we describe the synthesis, optical properties, and solid state structural characterization of various Re(I)(CO)₃(2,2’-bipyridine)L complexes encapsulated within the Zn(II)-trimesic acid based MOF, USF2. Effects of encapsulation on the Re(I) complex will be discussed as well as the consequences of confinement of the overall catalytic mechanism.