in tetrahydrofuran dissolution of Ru-complex in dry THF (under N2), addn. of CpNa in THF, stirring for 3 h; evapn. of THF to dryness on a rotary evaporator, addn. of a mixt. of CCl4, silica gel and sand, evapn. of CCl4, addn. to a silica/CCl4 column, elution (CCl4), evapn. of solvent, product is slurried in cold MeOH, filtration;