Structural Transformable Coulomb Lattice of n-Type Semiconductors for Guest Sorption.

In recent years, highly designable organic porous materials have attracted considerable attention in the development of new types of molecular adsorption-desorption materials. The adsorption-desorption process also changes the electronic structure via the existence of guest molecules. Therefore, it is possible to change the physical property during the guest adsorption-desorption cycle using an appropriate chemical design of the host crystal lattice. As the development of n-type organic semiconductors has been limited, we focused on designing an n-type organic semiconductor material to control the host crystal lattice, electronic dimensionality, chemical stability, and high electron mobility using an ionic naphthalenediimide ( NDI ) derivative. Low symmetrical dianionic bis(benzene- m -sulfonate)-naphthalenediimide ( m - BSNDI 2- ) forms various types of single-crystal (M + ) 2 ( m - BSNDI 2- )· n (guest) with a combination of M + = Na + , K + , Rb + , and guest = H 2 O, CH 3 OH. Four crystals of (K + ) 2 ( m - BSNDI 2- )· n (H 2 O), (K + ) 2 ( m - BSNDI 2- )· n (CH 3 OH), α-(K + ) 2 ( m - BSNDI 2- ), and β-(K + ) 2 ( m - BSNDI 2- ) were transformable using the guest adsorption-desorption cycle. Two kinds of single-crystal (K + ) 2 ( m - BSNDI 2- )· n (CH 3 OH) with n = 0 and 2.0 showed a single-crystal to single-crystal (SCSC) transformation through CH 3 OH desorption. On the contrary, five kinds of single crystals with n = 0, 3.0, 3.3, 4.75, and 5.5 were identified in the single-crystal X-ray structural analyses of (K + ) 2 ( m - BSNDI 2- )· n (H 2 O). Systematic change of the ionic radii in (M + ) 2 ( m - BSNDI 2- ) modified the crystal lattice flexibility for the guest adsorption-desorption cycles.