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The Heaviest Bottleable Metallylone: Synthesis of a Monatomic, Zero‐Valent Lead Complex (“Plumbylone”)

Xu, Jian; Pan, Sudip; Yao, Shenglai; Frenking, Gernot; Driess, Matthias

FG Metallorganische Chemie und Anorganische Materialien

The elusive plumbylone {[SiII(Xant)SiII]Pb0} 3 stabilized by the bis(silylene)xanthene chelating ligand 1, [SiII(Xant)SiII=PhC(NtBu)2Si(Xant)Si(NtBu)2CPh], and its isolable carbonyl iron complex {[SiII(Xant)SiII]Pb0Fe(CO)4} 4 are reported. The compounds 3 and 4 were obtained stepwise via reduction of the lead(II) dibromide complex {[SiII(Xant)SiII]PbBr2} 2, prepared from the bis(silylene)xanthene 1 and PbBr2, employing potassium naphthalenide and K2Fe(CO)4, respectively. While the genuine plumbylone 3 is rather labile even at −60 °C, its Pb0→Fe(CO)4 complex 4 turned out to be relatively stable and bottleable. However, solutions of 4 decompose readily to elemental Pb and {[SiII(Xant)SiII]Fe(CO)3} 5 at 80 °C. Reaction of 4 with [Rh(CO)2Cl]2 leads to the formation of the unusual dimeric [(OC)2RhPb(Cl)Fe(CO)4] complex 6 with trimetallic Rh−Pb−Fe bonds. The molecular and electronic structures of 3 and 4 were established by Density Functional Theory (DFT) calculations.