The reaction of 1, l'-dialkynylferrocene (eta5-C5H4C=CR)2Fe (1) (R=Ph,
SiMe3, Me, Fc; Fc=ferrocenyl) with excess octacarbonyldicobalt (2) re
sults in the formation of dark green complexes (eta5-C5H4C-CR)2Fe{Co2(
CO)6}2 (3) (R=Ph, SiMe3, Me, Fc), in which a Co2(CO)6 group coordinate
s to each of the two C-C bonds of 1. When 1, 1'-di(phenylethynyl)ferro
cene (1a) was treated with an equimolar amount of 2, (eta5-C5H4C=CPh)2
Fe{Co2(CO)6), as well as 3a, was obtained.