A phenanthroline-terpyridine hybrid as a chameleon-type ligand in a reversible metallosupramolecular rearrangement.

Phenanthroline-terpyridine hybrid 1 was designed as a chameleon-type ligand to satisfy both HETPHEN and HETTAP coordination modes. In the presence of Cu(+), 1 exclusively self-assembled to triangle T1, whereas Zn(2+) addition produced a 2:1 mixture of triangle T2 and square S2. Interconversion between T1 and (T2 + S2) states was triggered by the addition of Zn(2+) and reversed by selectively removing Zn(2+) with ligand 7.