in petroleum ether addn. of azo compd. to Fe-compd. in petroleum ether (-30°C), standing at room temp. (24 h); filtn., concn. and chromy. on silica gel, elution with petroleum ether gives traces of Fe3(CO)12 and triiron compd., then elution with petroleum ether/CH2Cl2 gives semidine complex;

in petroleum ether addn. of azo compd. to Fe-compd. in petroleum ether (-30°C), standing at room temp. (24 h); filtn., concn. and chromy. on silica gel, elution with petroleum ether gives traces of Fe3(CO)12 and triiron compd., then elution with petroleum ether/CH2Cl2 gives semidine complex;