Nucleophilic Attack at Pentaarsaferrocene [Cp*Fe(η5‐As5)]—The Way to Larger Polyarsenide Ligands

Abstract

AbstractBy the reaction of [Cp*Fe(η5‐As5)] (I) (Cp*=C5Me5) with main group nucleophiles, unique functionalized products with η4‐coordinated polyarsenide (Asn) units (n=5, 6, 20) are obtained. With carbon‐based nucleophiles such as MeLi or KBn (Bn=CH2Ph), the anionic organo‐substituted polyarsenide complexes, [Li(2.2.2‐cryptand)][Cp*Fe(η4‐As5Me)] (1 a) and [K(2.2.2‐cryptand)][Cp*Fe{η4‐As5(CH2Ph)}] (1 b), are accessible. The use of KAsPh2 leads to a selective and controlled extension of the As5 unit and the formation of the monoanionic compound [K(2.2.2‐cryptand][Cp*Fe(η4‐As6Ph2)] (2). When I is reacted with [M]As(SiMe3)2 (M=Li ⋅ THF; K), the formation of the largest known anionic polyarsenide unit in [M′(2.2.2‐cryptand)]2[(Cp*Fe)4{μ5‐η4:η4:η3:η3:η1:η1‐As20}] (3) occurred (M′=Li (3 a), K (3 b)).