Sterics and metal-ion radius control the self-assembly of [M2L3] helicates

The interplay of many factors influences the outcomes of self-assembly reactions. Using an acetylene-appended quaterpyridine ligand we show that both the size of the metal ion and the presence of steric repulsion between the acetylene groups result in the exclusive formation of [M2L3] helicates rather than a helicate/tetrahedron equilibrium.