Hydride reduction of the cations {(η5-C5H5)Fe[(Ph2PCH2)3CMe]}PF6, {(η5-C5H5)-Ru[(Ph2PCH2CH2)2PPh]} PF6, and {(η5-C5H5)Ru[(Ph2PCH2)3CMe]} PF6: regioselectivity and mechanism

Abstract

Reduction of the cation [η⁵-C₅H₅) Fe(tripod)] PF₆ with lithium aluminium hydride gives (η⁵-C₅H₅)FeH-(tripod)via an S_N1 mechanism, involving prior dissociation of a phosphine ligand leading to direct attack of hydride on the metal, in contrast with the related ruthenium cations [(η⁵-C₅H₅)RuL₃]PF₆(L₃= triphos or tripod) which give the cyclopentadiene complexes (η⁴-C₅H₆RuL₃via exo-hydride attack on the cyclopentadienyl ligand [tripod =(Ph₂PCH₂)₃CMe; triphos =(Ph₂-PCH₂CH₂)₂PPh].