Core/shell oligometallic template synthesis of macrocyclic hexaoxime.

A 36-membered macrocyclic hexaoxime was quantitatively obtained by [3 + 3] condensation of dialdehyde 2 with diamine 3 using La3+ (core metal) and Zn2+ (shell metal) as a novel core/shell template, while the yield was very low in the absence of the metal ions. The high yield can be attributed to the efficient formation of a 3:3:1 complex of dialdehyde 2, Zn2+, and La3+, which readily gives the macrocycle keeping the Zn3La core/shell tetranuclear cluster structure.