Reactions of In–Zn bonds with organic azides: products that result from hetero- and homo-bimetallic behaviour

Abstract

The indyl anion, K[In(NON^Dipp)] (NON^Dipp = [O(SiMe₂NDipp)₂]²⁻, Dipp = 2,6-iPr₂C₆H₃) reacts with group 12 compounds M(BDI^R)Cl (M = Zn, Cd; BDI = [HC{C(Me)NR}₂]⁻, R = 2,4,6-Me₃C₆H₂ (Mes), Dipp) to afford the heterobimetallic compounds (NON^Dipp)In–M(BDI^R) that contain the first In–Zn and In–Cd bonds. The reactivity of the In–Zn bonds towards organic azides, R′N₃ (R′ = Mes, Dipp, Ph) was investigated. (NON^Dipp)In–Zn(BDI^Mes) reduces MesN₃via an isolable triazenide intermediate to generate the bridging imido compound, (NON^Dipp)In–(μ-NMes)–Zn(BDI^Mes). Similar reactivity is noted from early–late heterobimetallic complexes. Under the same conditions, PhN₃ reacts to afford a product that contains a bridging tetraazenide ligand, which is formed from the formal (2 + 3)-cycloaddition of second azide to an indium-imido bond. However, increasing the bulk of the BDI-ligand in (NON^Dipp)In–Zn(BDI^Dipp) leads to reductive coupling of PhN₃ to give the hexazene complex. This mode of reactivity is reminiscent of the reductive behaviour of homobimetallic compounds.