Transfer of polyantimony units

Chem Sci. 2021 Jun 17;12(28):9726-9732. doi: 10.1039/d1sc02498a. eCollection 2021 Jul 21.

Abstract

Transfer reagents are useful tools in chemistry to access metastable compounds. The reaction of [Cp''2ZrCl2] with KSb(SiMe3)2 leads to the formation of the novel polyantimony triple decker complex [(Cp''Zr)2(μ,η1:1:1:1:1:1-Sb6)] (1, Cp'' = 1,3-di-tertbutyl-cyclopentadienyl), containing a chair-like Sb6 6- ligand. Compound 1 represents a valuable transfer reagent to form novel antimony ligand complexes. Thus, the reaction of 1 with CpR-substituted transition metal halides of nickel, cobalt and iron leads to the formation of a variety of novel Sb n ligand complexes, such as the cubane-like compounds [(Cp'''Ni)43-Sb)4] (2) and [(Cp'''Co)43-Sb4)] (3a) or the complexes [(CpBnCo)33-Sb)2] (4) and [(Cp'''Fe)33-Sb)2] (5), representing a trigonal bipyramidal structure. Moreover, beside the transfer of Sb1 units, also the complete entity can be transferred as seen in the iron complex [(Cp'''Fe)33,η4:4:4-Sb6)] (6). DFT calculations shed light on the bonding situation of the products.