N–H cleavage vs. Werner complex formation: reactivity of cationic group 14 tetrelenes towards amines

Abstract

β-Diketiminate ligands featuring backbone NMe₂ groups have been exploited to access a series of two-coordinate cations of the type [(N-nacnac)E]⁺ (E = Si, Ge, Sn), whose reactivity towards N–H bonds has been investigated. While the heavier group 14 systems react via simple adduct formation, N–H oxidative addition occurs for E = Si consistent with differences in E^II/E^IV redox potentials. The structurally characterized Ge/Sn adducts can be viewed as models for the corresponding (transient) Si systems [(N-nacnac)Si·(NH₂R)]⁺ (R = H, ^tBu) – which are potential intermediates in the formation of [(N-nacnac)Si(H)(NHR)]⁺via a proton-shuttling mechanism.