Synthesis of [Re2(CO)8{μ-N2(C5H4)2}], Derived from the Reaction of [Re2(CO)8(MeCN)2] and Diazocyclopentadiene

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.