Dynamic Inversion of Stereoselective Phosphate Binding to a Bisurea Receptor Controlled by Light and Heat

A chiral bisurea anion receptor, derived from a first-generation molecular motor, can undergo photochemical and thermal isomerization operating as a reconfigurable system. The two possible cisconfigurations in the isomerization cycle are opposite in helicity, as is shown by CD spectroscopy. (HNMR)-H-1 titrations demonstrate that the Pand Mhelical cisisomers hold opposite enantioselectivity in the binding of binol phosphate, while anion complexation by the intermediate transisomer is not selective. The difference in the binding affinity of the enantiomers was rationalized by DFT calculations, revealing very distinct binding modes. Thus, the enantiopreferred substrate binding in this receptor can be inverted in a dynamic fashion using light and heat.