Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• different substituents on the alkyl chains have been used to prepare pseudorotaxanes with pillar[5]arenes and have opened potential applications in different fields [38][39][40][41][42][43]. So far, fabricating pseudorotaxanes containing more than two components is still a difficult task. Herein, we report

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• : aggregation; circular dichroism; chirality; click chemistry; macrocycles; pillar[5]arenes; Introduction Planar-chiral compounds are structurally appealing and potentially applicable in various functional materials such as chiral discriminators [1][2], chiral polymers, supramolecular sensors [3] and chiral

• versatile functionality [9] in recent years. Pillar[5]arenes [10], are cyclic pentamers composed of 1,4-dialkoxybenzene units connected through methylene bridges at the para-position and have a unique symmetrical architecture with an overall cylindrical or pillar-like shape. By virtue of their rigid and

• symmetrical structures, as well as highly tunable functionality, the studies on pillar[5]arenes have been developed rapidly in various areas, such as artificial transmembrane channels [11][12], molecular complexation [13][14] and nonporous adaptive crystals [15][16][17]. One of the features of pillar[5]arenes

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

• Tomoki Ogoshi,
• Tomohiro Akutsu and
• Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

• pseudo[1]catenane structure in CDCl3. The linear alkyl chains can act as guests for pillar[5]arenes, thus the pseudo[1]catenane structure was stable in CDCl3 [17][18][19]. In D2O, as in CDCl3, the proton signals from the alkyl chain ring (blue peaks, a–e) were also observed upfield (Figure 2c

• inside to the outside of the cavity, a competitive guest molecule, 1,4-dicyanobutane, was added. 1,4-Dicyanobutane was chosen because it forms highly stable 1:1 host–guest complexes with pillar[5]arenes (K > 104 M−1) [20]. Figure 2d shows the 1H NMR spectra of 3 in the presence of 1,4-dicyanobutane. In

• other pillar[5]arenes [17][20], and were assigned as the proton signals from the methylene protons of the 1,4-dicyanobutane in the cavity of pillar[5]arene 3. The complex formation of 3 and 1,4-dicyanobutane indicates the displacement of the alkyl chain ring from the inside to the outside of the cavity

Synthesis of diamido-bridged bis-pillar[5]arenes and tris-pillar[5]arenes for construction of unique [1]rotaxanes and bis-[1]rotaxanes

• Ying Han,
• Li-Ming Xu,
• Cui-Yun Nie,
• Shuo Jiang,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2018, 14, 1660–1667, doi:10.3762/bjoc.14.142

• sequential alkylation of ω-bromoalkoxy-substituted pillar[5]arenes with methyl or ethyl p-hydroxybenzoate followed by a hydrolytic reaction under basic conditions. Under catalysis of HOBt/EDCl, the amidation reaction of pillar[5]arene mono(oxybutoxy)benzoic acid with monoamido-functionalized pillar[5]arenes

• afforded diamido-bridged bis-pillar[5]arenes. 1H NMR and 2D NOESY spectra clearly indicated that [1]rotaxanes were formed by insertion of longer diaminoalkylene unit into the cavity of one pillar[5]arene with another pillar[5]arene acting as a stopper. The similar catalysed amidation reaction of pillar[5

• ]arene di(oxybutoxy)benzoic acid with monoamido-functionalized pillar[5]arenes resulted in the diamido-bridged tris-pillar[5]arenes, which successfully form the unique bis-[1]rotaxanes bearing longer than diaminopropylene diamido bridges. Keywords: bis-[1]rotaxane; mechanically interlocked molecule