The formation of a hydrated homochiral helix from an achiral zwitterionic salt, spontaneous chiral symmetry breaking and redox chromism of crystals.

A unique supramolecular helix assisted by water tetramers is obtained by static evaporation of aqueous solution of a zwitterionic salt, 1,1'-bis(4-carboxylatebenzyl)-4,4'-bipyridinium; spontaneous chiral symmetry breaking occurs in crystallization; interestingly, redox chromism behavior of crystals upon exposure to alcohol atmosphere has been observed.