Snapshots of sequential polyphosphide rearrangement upon metallatetrylene addition

Insertion and functionalization of gallasilylenes [(LSi)-Si-Ph-Ga(Cl)L-BDI] (L-Ph = PhC(NtBu)(2); L-BDI = [{2,6-iPr(2)C(6)H(3)NCMe}(2)CH]) into the cyclo-E-5 rings of [Cp*Fe(?(5)-E-5)] (Cp* = ?(5)-C5Me5; E = P, As) are reported. Reactions of [Cp*Fe(?(5)-E-5)] with gallasilylene result in E-E/Si-Ga bond cleavage and the insertion of the silylene in the cyclo-E-5 rings. [((LSi)-Si-Ph-Ga(Cl)L-BDI){(?(4)-P-5)FeCp*}], in which the Si atom binds to the bent cyclo-P-5 ring, was identified as a reaction intermediate. The ring-expansion products are stable at room temperature, while isomerization occurred at higher temperature, and the silylene moiety further migrates to the Fe atom, forming the corresponding ring-construction isomers. Furthermore, reaction of [Cp*Fe(?(5)-As-5)] with the heavier gallagermylene [(LGe)-Ge-Ph-Ga(Cl)L-BDI] was also investigated. All the isolated complexes represent rare examples of mixed group 13/14 iron polypnictogenides, which could only be synthesized by taking advantage of the cooperativity of the gallatetrylenes featuring low-valent Si(ii) or Ge(ii) and Lewis acidic Ga(iii) units/entities.

Automated summary

Insertion and functionalization of gallasilylenes into the cyclo-E-5 rings of [Cp*Fe(?(5)-E-5)] (E = P, As) have been reported. The reaction results in E-E/Si-Ga bond cleavage and the insertion of the silylene in the cyclo-E-5 rings. The isolated complexes represent rare examples of mixed group 13/14 iron polypnictogenides, which can only be synthesized by utilizing the cooperativity of gallatetrylenes.