Stack by Stack: From the Free Cyclopentadienylgermanium Cation Via Heterobimetallic Main‐Group Sandwiches to Main‐Group Sandwich Coordination Polymers

Heterobimetallic cationic sandwich complexes [M(μ‐Cp)M′Cp]+ of group 13 (M=Ga, In) and group 14 (M′=Ge, Sn) elements have been prepared as [WCA]− salts (WCA=Al(ORF)4; ORF=OC(CF3)3). Their molecular structures include free apical gallium or indium atoms. The sandwich complexes were formed in the reactions of [M(HMB)]+[WCA]− (HMB=C6Me6) with the free metallocenes [M′Cp2]. Their structures are related to known stannocene and stannocenium salts; the unprecedented germanium analogues, namely the free germanocenium cation [GeCp]+ and the corresponding triple‐decker complex cation [CpGe(μ‐Cp)GeCp]+, are described herein. By variation of the reaction conditions, these sandwich complexes can be transformed into the group 13/14 mixed cationic coordination polymer [{In(HMB)(μ‐SnCp2)}n][WCA]n. This polymeric chain motif was also successfully replicated by the synthesis of complexes [{Ga/In(HMB)(μ‐FeCp2)}n][WCA]n containing FeCp2 as a bridging ligand.
One, two, three, infinity… The syntheses of the free germanocenium cation, a series of heterobimetallic sandwich cations of groups 13 and 14, as well as cationic sandwich polymers containing group 13 hexamethylbenzene cations bridged by stannocene and ferrocene are described.