Dimer of Diruthenium Compound Bridged by 1,1′-Diethynylferrocene: Ferrocene as a Weak Mediator for Electronic Coupling

The reaction between Ru-2(ap)(4)Cl (ap = 2-anilinopyridinate) and lithiated 1,1'-diethynylferrocene resulted in the expected product 1,1'-[Ru-2(ap)(4)(C C)](2)Fc (1) and 1-(Me3SiC C), 1'-1'-[Ru-2(ap)(4)(C C)](2)Fc (1) and 1-(Me(3)Sic C), 1'-[Ru-2(ap)(4)(C C)]Fc (2) as a byproduct. X-ray diffraction study of compound 1 revealed an anti arrangement of two Ru-2(ap)(4)(sigma-C C) fragments around the Fc unit. Cyclic and differential pulse voltammetric (CV and DPV) measurements indicated that two Ru-2 termini in 1 are weakly coupled in the reduced form. Also reported is the MO analysis of coupling mechanism based on the extended Huckel calculation of 1.