Synthesis, characterization, and some electrocatalytic properties of heteromultinuclear Fe I /Ru II Clusters

A series of new heteromultinuclear Fe I /Ru II clusters are described. The complexes ( η 6 ‐arene)RuFe 2 S 2 (CO) 6 (arene = p ‐cymene 1 , C 6 Me 6 2 ) and Fe 2 [ μ ‐S (Cp*Ru)(CO) 2 ] 2 (CO) 6 (Cp* = η 5 ‐C 5 Me 5 ) ( 3 ) were prepared by the reduction reactions of ( μ ‐S) 2 Fe 2 (CO) 6 with 2 equiv of LiHBEt 3 , followed by treatment ( μ ‐SLi) 2 Fe 2 (CO) 6 with ruthenium‐arene complexes Ru 2 ( μ ‐Cl) 2 Cl 2 ( η 6 ‐arene) 2 or Cp*Ru (CO) 2 Cl in 22–33% yields. Further reactions of 1 and 2 with 1 equiv of triphenylphosphine in the presence of the decarbonylating agent Me 3 NO·2H 2 O, afforded the corresponding monophosphine‐substituted Fe I /Ru II complexes ( η 6 ‐arene)RuFe 2 S 2 (CO) 5 (Ph 3 P) (arene = p ‐cymene 4 , C 6 Me 6 5 ) in 75% and 78% yields. While treatment of parent complex 1 or 2 with 1 equiv of diphosphine Ph 2 PCH 2 PPh 2 (dppm) in xylene at reflux temperature resulted in the formation of the diphosphine‐bridged RuFe 2 S 2 (CO) 9 derivate RuFe 2 S 2 (CO) 7 (dppm) ( 6 ). The possible pathway for the formation was proposed. Two isomers of novel macrocyclic complexes involve the ( η 6 ‐arene) Ru‐bridged quadruple‐butterfly Fe/S clusters [{ μ ‐S (CH 2 ) 3 S‐ μ }{( μ ‐CS 2 )Fe 2 (CO) 6 } 2 ] 2 [( η 6 ‐arene)Ru] 2 (arene = p ‐cymene 7a and 7b , C 6 Me 6 8a and 8b ) were isolated by reactions of two μ ‐CS 2 ‐containing dianion [{ μ ‐S (CH 2 ) 3 S‐ μ }{( μ ‐S=CS)Fe 2 (CO) 6 } 2 ] 2− with [Ru 2 ( μ ‐Cl) 2 Cl 2 ( η 6 ‐arene) 2 ], in which the propylene groups are attached to two S atoms by ee and ea types of bonds respectively. All the new complexes 1 – 8 have been characterized by elemental analysis, spectroscopy, and particularly for 1 – 6 , 7b and 8a by X‐ray crystallography. In addition, the electrochemical properties of representative complexes 1 – 4 and 6 have been investigated.