Surprising Substituent Effects on the Self-Assembly of Helicates from Bis(bipyridyl) BINOL Ligands

A number of different bis(bipyridyl) BINOL ligands were prepared using a convergent building block approach, These were studied with regard to their ability to undergo self-assembly to dinuclear helicatcs upon coordination to suitable late-transition-metal ions. Surprisingly, the substituents at the periphery of the ligand structure were found to have a marked influence on the outcome of the self-assembly processes with regard to the helicates composition, the stereoselectivity of the helicate formation, their redox reactivity, and their electronical properties as scrutinized by NMR- and CD-spectroscopic methods as well as ESI-mass spectrometric methods.