Synthesis of μ-Diborolyl Triple-decker complexes by electrophilic stacking. Similar bonding properties of anions [CpCo(1,3-C 3B 2H 5)]- and Cp- toward transition metals

Triple-decker complexes with a bridging diborolyl ligand CpCo(μ-1,3-C 3B 2Me 5)M(ring) (M(ring) = RuCp, 4; RuCp*, 5; Co(C 4Me 4), 6) were synthesized by electrophilic stacking of the sandwich anion [CpCo(1,3-C 3B 2Me 5)]- with the [(ring)M(MeCN) 3]+ cations. Structures of 4-6 were confirmed by X-ray diffraction. The electrochemical and spectroelectrochemical behavior of the complexes prepared was studied. DFT calculations of the redox potentials were also performed. Similar bonding properties of anions [CpCo(1,3-C 3B 2R 5)]- and [C 5R 5]- (R = H, Me) toward [M(ring)]+ cations were established both experimentally (synthesis, electrochemistry, and X-ray diffraction) and theoretically (energy decomposition and Mulliken population analysis). © 2009 American Chemical Society.