Self-assembly and crystal structure of a novel octadecametallic square box composed of 52 single components.

Reaction of divalent hexacoordinate metal ions with either tetradentate N-(2-piridylmethyl)iminodiethanol (3; H2L4) or tridentate N-(2-chlorobenzyl)iminodiethanol (5; H2L5) resulted in the formation of two completely different products. Starting from nickel(II) acetate and tetradentate 3, linear trinuclear complex [[Ni(HL4)]2-Ni(OAc)2(HCO2)2] (4) was formed. However, when tridentate 5 was allowed to react with cobalt(II) acetate, the novel octadecametallic square box [Na2-(Co4(HL5)3(OAc)5]4(HCO2)2] (6) was isolated. Chiral 6 has D2-molecule symmetry and crystalizes with both enantiomers in the unit cell. The structures of all new compounds were determined unequivocally by single-crystal X-ray analyses.