Synthesis and Helicate Formation of a New Family of BINOL-Based Bis(bipyridine) Ligands

A new family of BINOL-based bis(bipyridine) ligands 1-3 (BINOL = 2,2'-dihydroxy-1,1'-binaphthyl) was prepared in enantiomerically pure form. Whereas the coordination of zinc(II) ions to these ligands did not result in the selective formation of a specific metallosupramolecular aggregate, 1-3 were found to undergo highly diastereoselective self-assembly to D-2-symmetric dinuclear double-stranded helicates upon coordination to silver(I) and copper(I) ions and to D-3-symmetric dinuclear triple-stranded helicates upon coordination to iron(II) as demonstrated by mass spectrometry and by NMR and CD spectroscopy in combination with quantum chemical calculations.