Di‐, Tetra‐, Penta‐ and Polynuclear Zinc Complexes Supported by a Flexible Tetradentate Schiff Base Ligand

Abstract

AbstractWhen treated with Et2Zn, the tetradentate Schiff base N,N′‐ethylenebis(4‐iminopentan‐2‐one) (H2L) led to the formation of dimers, [L2Zn2], a tetranuclear complex, [L4Zn4] (1) and a polymeric material [LZn(Et)]n (2), thus highlighting the coordinative versatility of the ligand. Halogenation of 1 with SO2Cl2 or Br2 afforded in moderate yield the dinuclear zinc complexes [LZn(thf)·ZnCl2] (3) and [LZn(thf)·ZnBr2] (4). [LZn·ZnI(μ‐OEt)]2 (5) was isolated from the reaction of an in situ generated mixture of 1 and 2 with iodine. This product likely results from adventitious oxygen in the reaction mixture. This was seemingly confirmed by the diffusion of air into a solution of 2 in toluene, thereby resulting in a pentanuclear zinc complex, [(LZn·ZnEt)2{Zn(μ‐OEt)4}] (6). Complex 6 features a central Zn(OEt)4 unit, in which the ethoxide groups bridge two dinuclear fragments. The identities of complexes 1–6 were conclusively identified by X‐ray crystallography, thereby revealing similar structural features that were confirmed by spectroscopic data and, for 1–5, supported by DFT calculations.