Structural and Electrochemical Properties of a Ruthenium–Diiron Dithiolene Complex

The ruthenium–diiron dithiolene complex [(η 6 ‐C 6 Me 6 )Ru(CO)(µ‐CO) 2 Fe 2 (µ‐bdt)(CO) 4 ] ( 2 ) (bdt = 1,2‐benzenedithiolate) was synthesized, and two crystallographic isomers, which depend on the recrystallization temperature, were isolated; specifically, 2 and its isomer ( 2′ ) were obtained at –30 °C and room temperature, respectively. A single crystal of 2 was converted to 2′ by leaving it in hexane at room temperature for one week. A single crystal of 2′ did not convert to 2 in hexane at –30 °C. However, 2 could be obtained by the recrystallization of 2′ from a mixed solvent of dichloromethane and hexane. These results indicate that 2 is the most stable form in solvent. The isomerization occurs because of the stability of the 2′ packing structure compared with that of 2 . Additionally, 2 was found to act as a catalyst for proton reduction; catalytic proton reduction occurred at a potential of –2.1 V and 250 µA in acetic acid (50 equiv.).