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.