X-ray, 13 C NMR, and DFT studies on the cationic Ru(IV) allyl complex Ru(Cp*)Cl(CH 3 CN)(η 3 -PhCHCHCH 2 ), as a PF 6 salt, have revealed a marked asymmetry in the bonding of the allyl ligand, which can be interpreted as arising from differences in π-bonding from the metal center to the two terminal allyl carbons. This asymmetry in the bonding is offered as an explanation for the observed control of regioselectivity in the Rucatalyzed allylic alkylation reaction.

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New triple-decker complexes with bridging tetramethylcyclopentadienyl ligands were synthesized by the reaction of electrophilic metal fragments with octamethylferrocene, Cp′2Fe (Cp′ = C5Me4H). The reaction of coordinatively unsaturated ruthenium cations [(C5R5)Ru]+ (R = H, CH3) with Cp′2Fe afforded purple-colored heterometallic triple-decker complexes [(C5R5)Ru(μ-Cp′)FeCp′]+ by direct electrophilic addition. Surprisingly, the analogous reaction with the coordinatively unsaturated manganese cation [Mn(CO)3]+ and Cp′2Fe produced a blue homometallic triple-decker complex, [Cp′Fe(μ-Cp′)FeCp′]+, by ring abstraction and subsequent addition of the newly generated cation [Cp′Fe]+ to an equivalent of Cp′2Fe. Three air-stable triple-decker complexes, [Cp′Fe(μ-Cp′)FeCp′]+ (2), [CpRu(μ-Cp′)FeCp′]+ (3), and [Cp*Ru(μ-Cp′)FeCp′]+ (4), have been characterized by NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction.

Chemical reduction of a series of (η6-benzothiophene)Mn(CO)3 + complexes (10a−c) under CO affords neutral dimanganese metallathiacyclic complexes (12a−c), which have a Mn(CO)4 moiety inserted into the C(aryl)−S bond. Reduction of (η6-benzothiophene)Ru(C6Me6)2+ in the presence of CO and (η6-1-Me-naphthalene)Mn(CO)3 + affords an analogous cationic bimetallic (15), which is converted to a neutral cyclohexadienyl complex (16) by hydride addition to the carbocyclic benzothiophene ring. The sulfur atom in the metallathiacyclic ring in 12 and 16 is nucleophilic and reacts with electrophiles CF3SO3Me, HBF4, and W(CO)5(THF) to afford complexes such as 6, 14, and 17. Treatment of 12 with H2 results in hydrogenolysis of the Mn−C σ bond and formation of the bimetallic Mn2(CO)8(H)(SCHCHPh) (8), which contains a Mn−Mn bond and bridging hydride and thiolate ligands. Reaction of 6 and 17 with H2 results in desulfurization of the benzothiophene and formation of a mixture of Mn(CO)5SR and [Mn(CO)4SR]2 (R = H, Me). Crystal structures are reported for 9 (R = Me), 12b, and 16.