Heterobimetallic unsaturated silicon clusters (siliconoids) with transition metal-expanded scaffolds

Abstract

We report a heterobimetallical unsaturated silicon cluster (siliconoid) with a formally anionic group 9 metal vertex (Ir) in close contact to the lithium counter-cation, thus constituting a rare example of transition metal–lithium interactions. The anionic cluster is obtained by reductive chloride elimination from the corresponding neutral siliconoid complex of iridium(I) chloride with lithium/naphthalene. The previously exohedral transition metal center is fully incorporated into the siliconoid cluster scaffold giving rise to an irida-heterosiliconoid reminiscent of the corresponding homonuclear Si₇ species. Despite the formal negative charge at the iridium center, the nucleophilic site is on one of the adjacent silicon vertices judging from the reactivity toward group 4 metallocene dichlorides, Cp₂MCl₂ (M = Zr, Hf). Under elimination of LiCl, the Cp₂MCl moieties in the heterobimetallic products are installed as pending functionalities under retention of the literally uncompromised iridasiliconoid core.