An Iodido‐Bridged Dimer of Cubane‐Type RuIr 3 S 4 Cluster: Structural Rearrangement to New Octanuclear Core and Catalytic Reduction of Hydrazine

Nitrogen‐fixing enzymes contain octanuclear metal–sulfur clusters at the active site, which are constructed on the basis of combined two cubic M 4 S 3 C skeletons. In this study, the dimer of cubane‐type RuIr 3 S 4 cluster [{(Cp*Ir) 3 (µ 3 ‐S) 4 Ru} 2 (µ 2 ‐I) 3 ]I ( 2 : Cp* = η 5 ‐C 5 Me 5 ) was synthesized via oxidation of [(Cp*Ir) 3 (µ 3 ‐S) 4 (CymRu)] (Cym = η 6 ‐ p ‐ i PrC 6 H 4 Me) with I 2 followed by ligand exchange. Two cubane cores are bridged by three iodido ligands in 2 , while these cubes are fused into a unique Ru 2 Ir 6 S 8 framework by 2e‐reductuion to give [(Cp*Ir) 6 Ru 2 (µ 3 ‐S) 8 ][I] 2 . Addition of excess PhNHNH 2 to 2 cleaved the dimer structure to form the hydrazine adduct of single cubane [(Cp*Ir) 3 (µ 3 ‐S) 4 {RuI(NH 2 NHPh) 2 }]I. Reduction of N 2 H 4 with Cp 2 Co and [HNEt 3 ][BF 4 ] was catalyzed by 2 in much higher rate than disproportionation of N 2 H 4 . The molecular structures of all new cluster compounds were characterized by X‐ray diffraction studies.