to about 2 particularly suitable organomagnesium compounds include for example di n butyl magnesium n butyl sec butyl magnesium diisopropyl magnesium di n hexyl magnesium isopropyl n butyl magnesium ethyl n hexyl magnesium ethyl n butyl magnesium di n octyl magnesium butyl octyl and such complexes as di n butyl magnesium 1 3 aluminum triethyl di n butyl magnesium 1 6 aluminum triethyl mixtures thereof and the like suitable oxygen containing compounds include for example water carbon dioxide hydroxyl containing organic compounds such as alcohols glycols polyoxyalkylene glycols and the like aldehydes ketones acetals ketals carboxylic acids carboxylic acid esters orthoesters or halides carboxylic acid anhydrides organic carbonates mixtures thereof and the like wherein each r is a hydrocarbyl group having from 1 to about 20 preferably from 1 to about 10 carbon atoms or a halogen nhr or nh 2 substituted hydrocarbyl group having from 1 to about 20 preferably from 1 to about 10 carbon atoms each r 39 is independently a divalent hydrocarbyl group having from 1 to about 20 preferably from 1 to about 10 carbon atoms each r 34 is independently hydrogen a hydrocarbyl group having from 1 to about 20 preferably from 1 to 10 carbon atoms or a halogen nhr or nh 2 substituted hydrocarbyl group having from 1 to about 20 preferably from 1 to about 10 carbon atoms at least one of which is hydrogen z is a multivalent organic radical containing from 2 to about 20 carbon atoms n has a value from zero to about 10 and.