in dichloromethane exclusion of moisture; addn. of org. compd. to suspn. of Mo-compd. in CH2Cl2 (room temp.), boiling (14 h); partial distn. of CH2Cl2, addn. of CCl4, sepn., evapn. (vac.), washing (CCl4), drying, recrystn. (CH2Cl2/diisopropyl ether), filtn., washing (CH2Cl2), drying (vac.); elem. anal.;