Construction of hetero-four-layered tripalladium(II) cyclophanes by transannular π...π interactions

A synthetic strategy for the generation of new molecular species utilizing a provision of nature is presented. Nano-dimensional (23(2)×21(1)×16(1) ų) hetero-four-layered trimetallacyclophanes were constructed by proof-of-concept experiments that utilize a suitable combination of π...π interactions between the central aromatic rings, tailor-made short/long spacer tridentate donors, and the combined helicity. The behavior of the unprecedented four-layered metallacyclophane system offers a landmark in the development of new molecular systems. Hetero-four-layered tripalladium(II) cyclophanes have been prepared. The synthesis of this series of new compounds was accomplished by a combination of effective transannular π...π interactions, tailor-made short/long tridentate ligands, and Lewis basicity of donating groups.