DIBPillar[n]arenes (n = 5, 6): Syntheses, X-ray Crystal Structures, and Complexation with n-Octyltriethyl Ammonium Hexafluorophosphate

Abstract

DIBPillar[n]arenes (n = 5, 6) were synthesized. They showed different host-guest properties with n-octyltriethyl ammonium hexafluorophosphate G due to their different cavity sizes. DIBpillar[5]arene showed no complexation with G, while DIBpillar[6]arene formed a 1:1 complex with G with an association constant of 334 (±24) M(-1) in chloroform. In this letter, the first pillar[6]arene crystal structure and the first investigation of the host-guest chemistry of pillar[6]arenes are reported.

New Synthetic Host Pillararenes: Their Synthesis and Application to Supramolecular Materials

“…Cucurbit [7]uril binds a variety of positively charged polyaromatic compounds and bulky hydrocarbons such as adamantanes and bicyclooctanes. 18 Cations including bulky 1,4-diazabicyclo[2.2.2]octane G33 (Run 1), 56 adamantane G34 (Run 3), 73 triethylammonium G35 (Run 4), 32 and azobenzene G36 (Run 5) 66 moieties are therefore suitable guests for pillar [6]arene derivatives (Table 3 and Figure 10). These cationic guests are too large to form stable hostguest complexes with pillar [5] Scheme 11.…”

Four Pillar[5]arene Constitutional Isomers: Synthesis, Crystal Structures, and Host‐Guest Complexation of Their Derivatives with Paraquat in Water

“…However, the introduction of carboxylate anions at upper and/or lower rims can improve the solubility of pillar-[n]arenes in aqueous media, [28][29][30][31] thus making it possible to study the host-guest properties of pillar[n]arenes in water, which is an environmentally friendly solvent. [32] If its hydroquinone monomer is modified with two different substituents, a pillar [5]arene will have not only conformational isomers but also constitutional isomers. Theoretically, there will be four constitutional isomers for a nonsymmertric pillar [5]arene.…”

“…[32] If its hydroquinone monomer is modified with two different substituents, a pillar [5]arene will have not only conformational isomers but also constitutional isomers. Theoretically, there will be four constitutional isomers for a nonsymmertric pillar [5]arene. [34,35] In this study, we introduced pentyl and ester substituents at 1,4-position of hydroquinone and successfully prepared and separated four constitutional isomers of the corresponding nonsymmetric pillar [5]arene (Scheme 1).…”

“…They have different melting points, different NMR spectra and different crystal structures. Furthermore, the corresponding four anionic constitutional pillar [5]arene isomers derived from these four constitutional isomers showed different binding abilities with paraquat G in water. The association constants of 3a⊃G, 3b⊃G, 3c⊃G and 3d⊃G were determined to be (3. , respectively.…”

“…

A pillar [5]arene prepared from monomer 1 has four constitutional isomers. Although these constitutional isomers have the same molecular formula, their other properties that we have investigated are more or less different.

…”