The pentamethylmetallocenes CpMCp* (M = Ru, Fe) react with [Cp*Ru(OMe)]2/CF3SO3H in ether to give triple-decker salts [Cp*M(μ-Cp)RuCp*]CF3SO3 (4·CF3SO3, M = Ru; 5·CF3SO3, M = Fe) with an unsubstituted Cp as the bridging ligand. The structure of 4·CF3SO3-THF shows average metal-ring distances of 177.6(1) pm for the outer Cp* ligands and of 185.5(1) pm for the bridging Cp ring. The metalloelectrophiles [LM(solv)3]2+, generated from the dichlorides [(C6Me6)RuCl2]2, (Cp*RhCl2)2, (Cp*IrCl2)2, [(C4Me4)PtCl2]2, and AgCF3SO3 in MeNO2-d3, react with CpRuCp* at room temperature to undergo novel cyclopentadienyl transfer reactions, thus forming the cations [LMCp]+ besides 4+. With CpFeCp* labile triple-decker dications [LMCpFeCp*]2+” are formed in MeNO2-d3 at 0 °C while at higher temperature cyclopentadienyl transfer (for Ru, Ir) or alternatively redox reactions (for Rh, Pt) are observed. [(C6Me5)Ru(acetone)3] (CF3SO3)2 reacts with Fe(C5H4CHO)2 in acetone to give, after crystallization from CHC13, [(C6Me6)Ru(C6H4CHO)]CF3SO3-CHCl3 (70%). Extended Hückel MO calculations for CpFeCp* reveal weaker bonds to the Cp side and an asymmetric charge distribution with total net charges of −0.093 for the Cp and +0.104 for the Cp* fragments. This suggests that the observed regiochemistry of the stacking and ring ligand transfer reactions of 1 and 2 is primarily of electronic origin.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry