Toward Catalytic Hydrogenolysis of Chlorofluorocarbons with Group 8 and 9 Complexes

Abstract

Chlorofluorocarbons (CFCs) are man-made chemicals used for aerosols and refrigerants. CFCs are the sole cause of the hole in the ozone layer, and thus the use and production of these chemicals have been banned. There are, however, still CFCs waiting for disposal. Currently, CFCs are disposed of by burning in the presence of O2 and CH4 to form HF, HCl, and CO2. This thesis discusses a targeted catalytic cycle for the transformation of CFCs to HCFCs (hydrochlorofluorocarbons). Chapter 2 discusses the development of multiple systems suitable for the hydrogenolysis of dichloromethane, and the acid-base limitations for CFC hydrogenolysis specifically. Chapter 3 discusses another targeted system for catalysis, (tBuPOCOP)Rh(CO) (tBuPOCOP = κ3-C6H3-1,3-[OP(tBu)2]2). Pincer ligand metallation is presumed to proceed via initial coordination to the phosphorous atoms followed by C—H oxidative addition. While investigating the use of this system, protonation of (tBuPOCOP)Rh(CO) resulted in formation of [(tBuPOCOP)Rh(CO)H][B(C6F5)4]. When examined in the solid state, the compound was revealed to have an agostic interaction between Cipso—H and rhodium. This is one of few examples of an intermediate in the metallation of pincer ligands. The rhodium complex has been fully investigated in the solution state. Our studies have revealed exaggerated steric effects in (POCOP)Rh(CO) complexes in comparison to iridium analogues.