Self-Organization of -Crown Ether Derivatives into Double-Columnar Arrays Controlled by Supramolecular Isomers of Hydrogen-Bonded Anionic Biimidazolate Ni Complexes

Abstract

Anionic tris (biimidazolate) nickelate (II) ([Ni(Hbim) 3 ] − ), which is a hydrogen-bonding (H-bonding) molecular building block, undergoes self-organization into honeycomb-sheet superstructures connected by complementary intermolecular H-bonds. The crystal obtained from the stacking of these sheets is assembled into channel frameworks, approximately 2 nm wide, that clathrate two cationic K + -crown ether derivatives organised into one-dimensional (1D) double-columnar arrays. In this study, we have shown that all five cationic guest-included crystals form nanochannel structures that clathrate the 1-D double-columnar arrays of one of the four types of K + -crown ether derivatives, one of which induces a polymorph. This is accomplished by adaptably fitting two types of anionic [Ni(Hbim) − can assemble large cations such as K + crown-ether derivatives into double-columnar arrays by highly recognizing flexible H-bonding arrangements with two host networks of ΔΛ-ΔΛ-ΔΛ · · · and ΔΔΔ-ΛΛΛ · · · .