per-Hydroxylated Pillar[6]arene: Synthesis, X-ray Crystal Structure, and Host–Guest Complexation

Abstract

A per-hydroxylated pillar[6]arene was prepared. Single-crystal X-ray analysis demonstrated that its molecules are arranged in an up-to-down manner to form infinite channels in the solid state. Its host-guest complexation with a series of bispyridinium salts in solution was further investigated. It was found that the per-hydroxylated pillar[6]arene could form a 1:1 complex with paraquat in acetone with an association constant of 2.2 × 10(2) M(-1). This complex is a [2]pseudorotaxane as shown by its crystal structure, which is the first pillar[6]arene-based host-guest complex crystal structure.

Rotaxanes and pseudorotaxanes with threads containing viologen units

“…[108][109][110] Recently an intense research of cyclodextrin-based rotaxanes is observed. [111][112][113][114] One should mention here also pillarene-based pseudorotaxanes, 115,116 they are a new class of supramolecular structures yet not so thoroughly studied as other, longer known species. A growing attention is paid now to polyrotaxanes 117,118 and polypseudorotaxanes 119,120 which are a topic of increasing number of reports.…”

Spherical Vesicles Formed by Co-Assembly of Cyclic Pentagonal Pillar[5]quinone with Cyclic Hexagonal Pillar[6]arene

“…Tomoki Ogoshi, †, ‡,* Ryuta Sueto, † Kumiko Yoshikoshi, † Kazuma Yasuhara, § and Tada-aki Yamagishi † † Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan ‡ JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan § Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, 5630-0192, Japan Supporting Information Placeholder ABSTRACT: Mixing cyclic pentagonal pillar [5]quinone with cyclic hexagonal pillar[6]arene in a 12:20 molar feed ratio resulted in spontaneous production of vesicles, while assembly of pillar[6]arene and pillar [5]quinone alone produced hexagonal disks and wires, respectively. Incorporation of pentagonal pillar [5]quinone rings into hexagonal pillar[6]arene sheets gave curvature and contributed to the formation of vesicles.…”

Recent Advances of (Pseudo) Rotaxanes Constructed by Pillar[n]arenes

“…The host and guest structures of pseudrotaxanes formed by pyridine salts and pillar [5] [38] . Br Br…”