A Benzo-21-Crown-7/Secondary Ammonium Salt [<i>c</i>2]Daisy Chain

A [<i>c</i>2]daisy chain has been constructed from a heteroditopic monomer based on the benzo-21-crown-7/secondary ammonium salt recognition motif as shown by single crystal X-ray analysis. It has been further demonstrated that the complexation behavior of this heteroditopic monomer in solution can be controlled by changing the solution pH or adding/removing K⁺

A Benzo-21-Crown-7/Secondary Ammonium Salt [<i>c</i>2]Daisy Chain

A [<i>c</i>2]daisy chain has been constructed from a heteroditopic monomer based on the benzo-21-crown-7/secondary ammonium salt recognition motif as shown by single crystal X-ray analysis. It has been further demonstrated that the complexation behavior of this heteroditopic monomer in solution can be controlled by changing the solution pH or adding/removing K⁺

Construction of Multifunctional 3‑Amino-2-carbamimidoylacrylamides and Their Crystalline Channel-Type Inclusion Complexes

3-Amino-2-carbamimidoylacrylamides were efficiently prepared via a copper­(I)-catalyzed three-component reaction of sulfonylazides, propriolamides, and amidines. The synthesized compounds provided three kinds of crystalline structures based on the position of halogen. Two of them presented channel-type inclusion complexes with ethyl acetate through intermolecular hydrogen bonding, intermolecular C–H···π and π–π interactions, and van der Waals forces

Legislative Documents

Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents

Solid-State Self-Assembly of Heteroditopic Copillar[5]arenes

Self-assembly is a fundamental bottom-up tool for the construction of living or synthetic materials. Owing to the specific, definite, and directional host–guest interactions, heteroditopic monomers has become one of the classic models as building blocks in self-assembly investigation. Driven by the unique multiple CH···π interactions between the pillar[5]arene cavity and the linear n-alkyl group, copillar[5]arenes have become one of the simplest and optimal models for the construction of heteroditopic monomers in recent years. Here, by comparison of the reported crystal structures of heteroditopic copillar[5]arenes with six new ones (P6Br, P8Br, P6Im, P10Im, P4 ⊃ acetonnitrile, and P8Br ⊃ succinonitrile), we found that their self-assembly manner in the solid state was primarily decided by the competition of the pillar[5]arene cavity between the threading guest moiety and the solvent molecules (or external competitors). When the competitor had much higher affinity to the pillar[5]arene cavity, a traditional host–guest complex would be formed in the solid state. When the threading guest moiety showed much higher affinity, [cn]daisy chains (normally [c2]) would be formed. It was further found that only when they had similar bonding abilities with the pillar[5]arene cavity, [an]daisy chains could be formed in the solid state

Aliphatic Aldehyde Detection and Adsorption by Nonporous Adaptive Pillar[4]arene[1]quinone Crystals with Vapochromic Behavior

The detection and adsorption of volatile low-molecular-weight aliphatic aldehydes is of significance, owing to their physical volatility, chemical toxicity, and widespread applications in chemical industrial processes. Here, nonporous adaptive pillar[4]­arene[1]­quinone (<b>EtP4Q1</b>) crystals with vapochromic behavior are used for the volatile aliphatic aldehyde uptake and sensing. When desolvated <b>EtP4Q1</b> crystals (<b>EtP4Q1</b>α) are exposed to aliphatic aldehydes with different carbon chain lengths, they quantitatively adsorb vapors of these aldehydes, accompanied by different color changes. Crystal structure analyses show that the structure of <b>EtP4Q1</b> transforms from <b>EtP4Q1</b>α into the corresponding new structures after the adsorption of these aldehydes, which leads to different color changes. The selectivity of <b>EtP4Q1</b>α crystals, which function as both sensors and adsorbents upon exposure to mixed aldehyde vapors, is also explored. Finally, it is demonstrated that <b>EtP4Q1</b>α crystals can be recycled many times without loss of performance

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

A <i>per</i>-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 <i>per</i>-hydroxylated pillar[6]arene could form a 1:1 complex with paraquat in acetone with an association constant of 2.2 × 10² 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