In a similar approach for a different application, Dong et al. demonstrated the possibility of one-step sieving separation of a ternary gas mixture (C 2 H 2 /CO 2 /C 2 H 4 ) in flexible MOF NTU-65 We also note, in closing this section, that beyond adsorption, framework flexibility interplays with other physical properties, such as spin , photo-responsive behavior, luminescence, etc.