Conversion of Perfluorobenzyl Complexes of Rhodium to Fluorinated Oxarhodacycles

The perfluorobenzylrhodium complex [Cp*Rh(CO)(CF2C6F5)(I)], 1 (Cp* = C5Me5), reacts with N-methylmorpholine-N-oxide (NMO) with loss of CO2 and formation of the iodo-bridged dimer [Cp*Rh(μ2-I)(CF2C6F5)]2, 5, which has been characterized by X-ray crystallography. While attempts to prepare hydroxo complexes by reaction of [Cp*Rh(PMe3)(CF2C6F5)(I)], 3, with sources of hydroxide were unsuccessful, treatment of 3 with moist silver oxide affords the oxametallacycle [Cp*(PMe3)RhO(C6F4)CF2], 9, which undergoes rapid hydrolysis of the α-CF2 group by adventitious moisture to afford the crystallographically characterized analogue [Cp*(PMe3)RhO(C6F4)CO], 10. A brief discussion of possible mechanisms is presented.