Design and Synthesis of Box[6]arenes for 3D Charge-Transfer Co-Crystal Engineering via Macrocyclic Self-Complementary and Exo-Wall Interactions.

The construction of well-defined 3D charge-transfer (CT) co-crystals using new macrocyclic hosts to enable programmable functionality remains challenging due to the dimensional constraints imposed by conventional assembly strategies. Herein, we address this limitation using a new synthetic macrocycle named box[6]arene (B[6]A) with a flexible skeleton, which adopts two distinct conformations (B[6]Aα and B[6]Aβ). Crucially, the self-complementary and exo-wall CT co-assembly of B[6]A facilitates the construction of 3D macrocycle-based co-crystals (MCCs) with planar electron-deficient guests, including 1,2,4,5-tetracyanobenzene (TCNB), tetrafluoroterephthalonitrile (TFTN), and tetrachloroterephthalonitrile (TClTN).

Phenyl-Extended Resorcin[4]arenes: Synthesis and Highly Efficient Iodine Adsorption.

The continuous exploration of new analogs of calixarenes and pillararenes unlocks infinite opportunities in supramolecular chemistry and materials. In this work, we introduce a new class of macrocycle, phenyl-extended resorcin[4]arenes (ExR4), a unique and innovative design that incorporates unsubstituted phenylene moieties into the resorcin[4]arene scaffold. Single-crystal analysis reveals a chair-like conformation for per-methylated ExR4 (Me-ExR4) and a twisted "Figure-of-eight" shaped conformation for per-hydroxylated ExR4 (OH-ExR4).

[2]Biphenyl-extended pillar[6]arene functionalized silver nanoparticles for catalysis and label-free detection.

Synthetic macrocycles have served as principal tools for supramolecular chemistry since their establishment, and the investigation of macrocycles-aided organic-inorganic hybrid nanomaterials has also attracted broad interest in chemistry and material communities during the past decade owing to their widespread applications in optical sensing, catalytic degradation, biomedicine, and other related fields. Herein, a new class of silver nanoparticles (AgNPs) modified by anionic water-soluble [2]biphenyl-extended pillar[6]arene (WBpP6), namely WBpP6-AgNPs, is designed and synthesized through a facile one-pot method. WBpP6-AgNPs with good dispersion and stability exhibit efficient catalytic properties toward the hydrogenation of a series of aromatic nitro compounds and also show good performance in label-free detection toward diquat.

Grinding-induced supramolecular charge-transfer assemblies with switchable vapochromism toward haloalkane isomers.

Synthetic macrocycles have proved to be of great application value in functional charge-transfer systems in the solid state in recent years. Here we show a switchable on-off type vapochromic system toward 1-/2-bromoalkane isomers by constructing solid-state charge-transfer complexes between electron-rich perethylated pillar[5]arene and electron-deficient aromatic acceptors including 4-nitrobenzonitrile and 1,4-dinitrobenzene. These charge-transfer complexes with different colors show opposite color changes upon exposure to the vapors of 1-bromoalkanes (fading) and 2-bromoalkanes (deepening).

Macrocycle-Based Crystalline Supramolecular Assemblies Built with Intermolecular Charge-Transfer Interactions.

Synthetic macrocycles have served as principal tools for supramolecular chemistry, have greatly extended the scope of organic charge transfer (CT) complexes, and have proved to be of great practical value in the solid state during the past few years. In this Minireview, we summarize the research progress on the macrocycle-based crystalline supramolecular assemblies primarily driven by intermolecular CT interactions (a.k.

Pillararene-Inspired Macrocycles: From Extended Pillar[]arenes to Geminiarenes.

chemistry since their establishment due to their innate functional features of molecular recognition and complexation. The rapid development of modern supramolecular chemistry has also significantly benefited from creating new macrocycles with distinctive geometries and properties. For instance, pillar[]arenes (pillarenes), a relatively young generation of star macrocyclic hosts among the well-established ones (e.

A Water-Soluble Leggero Pillar[5]arene.

The study of aqueous-phase molecular recognition of artificial receptors is one of the frontiers in supramolecular chemistry since most biochemical processes and reactions take place in an aqueous medium and heavily rely on it. In this work, a water-soluble version of leggero pillar[5]arene bearing eight positively charged pyridinium moieties ( was designed and synthesized, which exhibited good binding affinities with certain aliphatic sulfonate species in aqueous solutions. Significantly, control experiments demonstrate that the guest binding performance of is superior to its counterpart water-soluble macrocyclic receptor in traditional pillararenes.

Modulating Supramolecular Charge-Transfer Interactions in the Solid State using Compressible Macrocyclic Hosts.

Modulating intermolecular charge-transfer (ICT) interactions between specific donor and acceptor species in host-guest systems is a big challenge and full of research value in supramolecular chemistry and materials science. In this work, a strategy to modulate the supramolecular ICT interactions in the solid state is developed by compressing the binding cavity of a macrocyclic host named perethylated leaning pillar[6]arene (p-EtLP6). The solid-state ICT affinities of p-EtLP6 toward multi-types of electron-deficient planar guests could be significantly enhanced by transforming the macrocyclic backbone from the original para-bridged mode into a hybrid para- and meta-bridged isomeric form (m-EtLP6).

Guest-induced amorphous-to-crystalline transformation enables sorting of haloalkane isomers with near-perfect selectivity.

The separation of haloalkane isomers with distillation-free strategies is one of the most challenging research topics in fundamental research and also gave high guiding values to practical industrial applications. Here, this contribution provides a previously unidentified solid supramolecular adsorption material based on a leggero pillararene derivative , which can separate 1-/2-bromoalkane isomers with near-ideal selectivity. Activated solids of with interesting amorphous and nonporous features could adsorb 1-bromopropane and 1-bromobutane from the corresponding equal volume mixtures of 1-/2-positional isomers with purities of 98.

Bottom-Up Solid-State Molecular Assembly via Guest-Induced Intermolecular Interactions.

The manipulation of molecular motions to construct highly ordered supramolecular architectures from chaos in the solid state is considered to be far more complex and challenging in comparison to that in solution. In this work, a bottom-up molecular assembly approach based on a newly designed skeleton-trimmed pillar[5]arene analogue, namely the permethylated leggero pillar[5]arene , is developed in the solid state. An amorphous powder of can take up certain guest vapors to form various ordered linker-containing solid-state molecular assemblies, which can be further used to construct a thermodynamically favored linker-free superstructure upon heating.

Enantioselective Synthesis of Quaternary Carbon Stereocenters by Asymmetric Allylic Alkylation: A Review.

Quaternary stereocenters are of great importance to the three-dimensionality and enhanced properties of new molecules, but the synthetic challenges in creating quaternary stereocenters greatly hinder their wide use in drug discovery, organic material design, and natural product synthesis. The asymmetric allylic alkylation (AAA) of allylic substrates has proven to be a powerful methodology for enantioselective formation of structure skeletons bearing single or more quaternary carbon centers in modern asymmetric organocatalysis. AAA has certain advantages in constructing the tetrasubstituted stereocenters, including but not limited to mild reactive conditions, effective reaction rates, new functional group introduction, and carbon chains length extension.

Asymmetric Organocatalysis Combined with Palladium Catalysis: Synergistic Effect on Enantioselective Mannich/α-Allylation Sequential Reactions of Pyrazolones in Constructing Vicinal Quaternary Stereocenters.

In this letter, an efficient one-pot asymmetric sequential reaction is achieved by organo/transition metal relay catalysis in constructing two consecutive C-C bonds, which involves enantioselective amino squaramide catalytic Mannich-type addition of pyrazolones to isatin-derived ketimines and a subsequent palladium catalyzed diastereoselective allylic alkylation of pyrazolones with allylic acetates. An array of novel pyrazolone-aminooxindole-propylene structural motifs are obtained in a high level of yield and with excellent enantio- and diastereoselectivity (up to 95% yield, >20:1 dr, >99% ee). This methodology features the formation of vicinal quarternary carbon-stereocenters, and the second all-carbon tetrasubstituted stereogenic center is induced by joint action of the achiral palladium catalysis and the chiral environment generated from the Mannich step.