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 [(CpFe)-Fe-R(CO)(2)](2) (Cp-R = C5Me5, EtC5Me4, 1,3-(Bu2C5H3)-C-t) with As-4 is examined. For C5Me5 and EtC5Me4, the pentaarsaferrocene derivatives [(CpFe)-Fe-R(eta(5)-As-5)] are formed together with [((CpFe)-Fe-R)(3)As-6] and [((CpFe)-Fe-R)(3)As-6{(eta(3)-As-3)Fe}], while for 1,3-(Bu2C5H3)-C-t only [((CpFe)-Fe-R)(3)As-6] is formed. The reaction of [(Me5C5Fe)(3)As-6{(eta(3)-As-3)Fe}] with Tl+ leads to [{(Me5C5Fe)(3)As6Fe}(2)(mu,eta(3):eta(3)-As-3)](2+) representing an unexpected dicationic cluster.