meso Myths: What Drives Assembly of Helical versus meso-

Both a triple helix as well as a meso complex are formed by the Ga(III) and Al(III) complexes with a bis-bidentate bis-hydroxypyridinone ligand H(2)L. The two forms are in equilibrium in solution, though formation of the helical structure in the presence of water, which as guest molecule finds sufficient space in the cavity of the helix, is favored (the structure of the helical H(2)O subset[Al(2)L(3)] complex is shown).