Trans-Tetracarbonyl iron complex

First, cis- and trans-2-phenylmethylenecyclopropanes-3-d were shown to give trimethyl-enemethane complexes with the deuterium at a location consistent only with disrotatory ring-opening (Figure 41). Second, reaction of 2,2-diphenylmethylenecyclopropane with a variety of iron carbonyl reagents allowed isolation of the methylenecyclopropane iron tetracarbonyl complex. This compound could be shown to give the trimethylenemethane complex on reaction with trimethylamine-N-oxide or diiron nonacarbonyl, both of which... 

Ligand isomerization must also occur in the photochemical transformation of cis- and trans-(1.2-dibromoethylene)iron tetracarbonyl to a binuclear complex (see section E7c), since both iron tetracarbonyls yield the same product with a trans-configurated C=C bond 202,285)... 

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