Photo-controllable binding and release of HP 2 O 7 3- using an azobenzene based smart macrocycle.

Herein, we describe the design and synthesis of an unusual azobenzene-bearing macrocycle 1 , whose trans isomer was found able to 100% transform into its cis configuration under photoirradiation, for selectively recognizing HP 2 O 7 3- with reversibly photo-controllable binding and release properties.