With  methanol; ascorbic acid powder in  dichloromethane  mixture of Os(VI)-complex and L-(+)-ascorbic acid is stirred in a MeOH/CH2Cl2 soln. at room temp. for 2 h; filtn., washing with CH2Cl2, combining of washing and filtrate and reducing to 5 ml, chromy. on silica gel (CH2Cl2/EtOH), evapn. of solvent, recrystn. (hot alcohol), elem. anal.;