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

Noncovalently bound and mechanically interlocked systems using pillar[n]arenes

Pillar[n]arenes are pillar-shaped macrocyclic compounds owing to the methylene bridges linking the para-positions of the units. Owing to their unique pillar-shaped structures, these compounds exhibit various excellent properties compared with other cyclic host molecules, such as versatile functionality using various organic synthesis techniques, substituent-dependent solubility, cavity-size-dependent host-guest properties in organic media, and unit rotation along with planar chiral inversion. These advantages have enabled the high-yield synthesis and rational design of pillar[n]arene-based mechanically interlocked molecules (MIMs). In particular, new types of pillar[n]arene-based MIMs that can dynamically convert between interlocked and unlocked states through unit rotation have been produced. The highly symmetrical pillar-shaped structures of pillar[n]arenes result in simple NMR spectra, which are useful for studying the motion of pillar[n]arene wheels in MIMs and creating sophisticated MIMs with higher-order structures. The creation and application of polymeric MIMs based on pillar[n]arenes is also discussed.

[1]Rotaxanes based on phosphorylated pillar[5]arenes

[1]Rotaxanes based on monosubstituted phosphorus-containing pillar[5]arenes have been synthesized by the Kabachnik–Fields reaction for the first time in good yields.

Covalently bridged pillararene-based oligomers: from construction to applications

Covalently bridged pillararene-based oligomers (CBPOs) are formed by covalent bonding of pillararene monomers, and they play a critical role in expanding the multi-disciplinary application of pillararenes due to their excellent molecular complexing ability, specially designed geometry and multifunctional linking groups. This article provides a comprehensive review of the synthesis and applications of CBPOs. The design and synthetic strategies of a series of CBPOs (dimers, trimers, tetramers and others) are first introduced. Many CBPOs with multi-cavities and unique geometry are very attractive and efficient building blocks for constructing novel smart supramolecular polymers (SPs) with different topological structures through host-guest interactions. We describe the methods of constructing various SPs based on CBPOs in detail. Furthermore, the extensive applications of CBPOs and CBPO-based SPs in recognition and detection of ions and organic small molecules, selective adsorption and separation, artificial light-harvesting systems, catalysis, drug delivery systems, and others are systematically introduced. Finally, the future challenges and perspectives for CBPOs are also highlighted.

Design, Synthesis, Antibacterial Evaluation and Molecular Docking Studies of Some Newer Baenzothiazole Containing Aryl and Alkaryl Hydrazides

The alarming rise of bacterial resistance is occurring worldwide and endangering the efficacy of antibiotics. Therefore, development of new and efficient antibacterial agents remains paramount. In the present work, we designed and synthesized a series of N'-(1,3-benzothiazol-2-yl)-substituted aryl/aralkyl hydrazides C1-C27 and evaluated them in vitro for their antibacterial activity. Among all tested compounds, C10, C15, and C24 showed potent activity against Staphylococcus aureus ATCC 43300 (MRSA). Minimum bactericidal concentration studies of synthesized compounds are performed against selected bacterial strains. Time kill kinetics showed that the compounds C10 and C15 possess bactericidal activity against MRSA ATCC 43300, while compound C24 possess bactericidal activity against S. aureus NCIM 5022. In the extra-precision docking, compounds C1-C27 exhibited interactions mainly with the N-terminal and central domains of S. aureus GyrB catalytic pocket. Binding free energy (ΔGbind ) of compounds C1-C27/3U2K complexes were computed by MM-GBSA approach. Free energy components indicated Coulomb energy term as favorable for binding, while van der Waals and electrostatic solvation energy terms strongly disfavored the binding. ADMET properties of synthesized compounds C1-C27 are also computed.

Pillar[6]arene-based supramolecular polymeric materials constructed via electrostatic interactions for rapid and efficient organic dye removal from water

The first pillar[6]arene-based supramolecular polymeric material constructed from electrostatic interactions was designed and prepared successfully. Importantly, it can adsorb and remove organic dye from water efficiently.