in dichloromethane; acetonitrile byproducts: ferrocene; addn. of ferrocenium tetrafluoroborate (0.20 mmol) to soln. of (Rh2(C2O4)(C8H12)2) (0.20 mmol) in CH2Cl2/CH3CN (1:1);; removal of solvent in vac.; extg. 3 times with ether to remove ferrocene; extg. with CH3CN; concg. ext. and layering with ether; crystn. after 12 h at -20°C; sepn., identification by IR, NMR and elem. anal.;;