Unusual Thiolate-Bridged Diiron Clusters Bearing the cis-HNNH Ligand and Their Reactivities with Terminal Alkynes

A series of well-defined thiolate-bridged diiron clusters bearing the cis-HNNH ligand, [CpFe(μ-SEt)2(μ-η11-HNNH)FeCp][PF6] (Cp = η5-C5Me4H or η5-C5Me5), are successfully prepared in high yields and fully characterized by spectroscopy and X-ray crystallography. Under moderate conditions, these new Fe/S clusters exhibit high activity, not only for the catalytic cleavage of the N−N bond of hydrazines but also for the activation and coupling of terminal alkynes.