in dichloromethane; acetonitrile Irradiation (UV/VIS); irradiation of Fe-complex with 1.5 equiv. of phosphine (150 W flood lamp, 4 h), cooling, filtration, concn., dissoln. in CH2Cl2, cooling to -10°C, bubbling SO2 through soln. for 2 min, stirring for 30 min, warming to room temp.; solvent removal, chromy. (Al2O3, hexane, then CHCl3), solvent removal (vac.), drying (1 mm Hg, overnight);

in water byproducts: β-cyclodextrin; heating Fe-complex with excess of phosphine to 60°C for 5 h; cooling, filtration;

in liquid sulphur dioxide Irradiation (UV/VIS); condensation of liquid SO2 onto Fe-complex at -10°C, stirring (-10°C, 2 h); evapn., solvent removal, chromy. (Al2O3, CHCl3), solvent removal, drying(1 mm Hg, overnight); elem. anal.;