The reaction of
[Re2(CO)8(MeCN)2] with
diazocyclopentadiene in refluxing tetrahydrofuran in a 1:1
molar ratio gave
[Re(CO)3(C5H5)]
(1), the cyclopentadienylidene complex
[Re2(CO)8(μ,η1:η5-C5H4)]
(2), and the
fulvalene complex
[Re2(CO)6(μ,η5:η5-C10H8)]
(3) in moderate overall yield. A similar reaction in a 1:2 molar
ratio gave almost exclusively the new compound
[Re2(CO)8{μ-N2(C5H4)2}]
(4) containing a novel diazo-bridging ligand.