Tautomerism-Coupled Self-Assembly and Transformations of Iminopyrrole Metallacages.

Abstract

Four discrete metallacages were obtained from the condensation of 2,5-diformylpyrrole and tren in the presence of Zn(II). The structures differed in nuclearity, size, and symmetry, with the number of templating cations playing a key role in defining the properties of the architecture. The diiminopyrrole coordination motif, a fundamental structural feature of assemblies, undergoes tautomerization in certain cases, yielding an iminoaminoazafulvene, which alters the assembly. The controlled interconversion between bi-, tetra-, and dodecanuclear cages was achieved through simple stimuli, highlighting the dynamic nature of these assemblies.