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Journal of Nanotechnology
Volume 2012 (2012), Article ID 216050, 10 pages
http://dx.doi.org/10.1155/2012/216050
Research Article

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

1Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo 162-8601, Japan
2Fukui University of Technology, Gakuen 3-6-1, Fukui 910-8505, Japan

Received 27 March 2012; Accepted 18 May 2012

Academic Editor: Hongmei Luo

Copyright © 2012 Makoto Tadokoro et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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)3] host arrays. One is a Δ Λ Δ Λ Δ Λ network with H-bonded linkages alternating between the two different optical isomers of the Δ and Λ types with flexible H-bonded [Ni(Hbim)3]. The other is a Δ Δ Δ Λ Λ Λ network of a racemate with 1-D H-bonded arrays of the same optical isomer for each type. Thus, [Ni(Hbim)3] 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 Δ Λ Δ Λ Δ Λ and Δ Δ Δ Λ Λ Λ .