The influence of differently substituted cyclopentadienyl CpR ligands on the reactivity of [CpRFe(CO)2]2 with yellow arsenic

The influence of differently substituted cyclopentadienyl Cp^R ligands on the reaction outcome of [Cp^RFe(CO)₂]₂ (Cp^R = C₅Me₅, EtC₅Me₄, 1,3-Bu₂tC₅H₃) with As₄ is examined. For C₅Me₅ and EtC₅Me₄, the pentaarsaferrocene derivatives [Cp^RFe(η⁵-As₅)] are formed together with [(Cp^RFe)₃As₆] and [(Cp^RFe)₃As₆{(η³-As₃)Fe}], while for 1,3-Bu₂^tC₅H₃ only [(Cp^RFe)₃As₆] is formed. The reaction of [(Me₅C₅Fe)₃As₆{(η³-As₃)Fe}] with Tl⁺ leads to [{(Me₅C₅Fe)₃As₆Fe}₂(μ,η³:η³-As₃)]²⁺ representing an unexpected dicationic cluster.