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

When treated with Et 2 Zn, the tetradentate Schiff base N , N′ ‐ethylenebis(4‐iminopentan‐2‐one) (H 2 L ) led to the formation of dimers, [ L 2 Zn 2 ], a tetranuclear complex, [ L 4 Zn 4 ] ( 1 ) and a polymeric material [ L Zn(Et)] n ( 2 ), thus highlighting the coordinative versatility of the ligand. Halogenation of 1 with SO 2 Cl 2 or Br 2 afforded in moderate yield the dinuclear zinc complexes [ L Zn(thf) · ZnCl 2 ] ( 3 ) and [ L Zn(thf) · ZnBr 2 ] ( 4 ). [ L Zn · 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, [( L Zn · 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.