Stoichiometry-controlled supramolecular chirality induction and inversion in bisporphyrin systems

[reaction: see text] Stoichiometry is found to be an effective tool for controlling supramolecular chirality induction and inversion processes. Chirality induction in the achiral syn ethane-bridged bis(zinc octaethylporphyrin) is achieved upon interaction with the enantiopure (R,R)-1,2-diphenylethylenediamine at the low molar excess region, to yield the right-handed chiral 1:1 tweezer complex. Further increase of the ligand concentration results in chirality inversion as the equilibrium shifts toward the extended left-handed 1:2 anti complex as a result of switching of the complex helicity.