Linear Positional Isomer Sorting in Nonporous Adaptive Crystals of a Pillar[5]arene

Here we show a new adsorptive separation approach using nonporous adaptive crystals of a pillar[5]­arene. Desolvated perethylated pillar[5]­arene crystals (<b>EtP5</b>α) with a nonporous character selectively adsorb 1-pentene (<b>1-Pe</b>) over its positional isomer 2-pentene (<b>2-Pe</b>), leading to a structural change from <b>EtP5</b>α to <b>1-Pe</b> loaded structure (<b>1-Pe</b>@<b>EtP5</b>). The purity of <b>1-Pe</b> reaches 98.7% in just one cycle and <b>EtP5</b>α can be reused without losing separation performance

Mechanochemical synthesis of pillar[5]quinone derived multi-microporous organic polymers for radioactive organic iodide capture and storage.

The incorporation of supramolecular macrocycles into porous organic polymers may endow the material with enhanced uptake of specific guests through host-guest interactions. Here we report a solvent and catalyst-free mechanochemical synthesis of pillar[5]quinone (P5Q) derived multi-microporous organic polymers with hydrophenazine linkages (MHP-P5Q), which show a unique 3-step N2 adsorption isotherm. In comparison with analogous microporous hydrophenazine-linked organic polymers (MHPs) obtained using simple twofold benzoquinones, MHP-P5Q is demonstrated to have a superior performance in radioactive iodomethane (CH3I) capture and storage. Mechanistic studies show that the rigid pillar[5]arene cavity has additional binding sites though host-guest interactions as well as the halogen bond (-I⋯N = C-) and chemical adsorption in the multi-microporous MHP-P5Q mainly account for the rapid and high-capacity adsorption and long-term storage of CH3I

Studying the electronic and charge transport properties of two cyclocarbazole derivates

Molecular systems have proven to be efficient active materials in electronics, being possible alternatives to the inorganic semiconductors used nowadays in electronic devices. For this reason, organic electronics has emerged as a research field with great potential and interest. In this project, an experimental and theoretical study of two carbazole-based macrocycles is presented (Figure 1). Specifically, we investigated the impact of the inclusion of acetylene groups on the electronic and molecular structures of these macrocycles, as well as their potential as charge transporting materials. The first studied compound (Cz) is composed by four carbazole groups linked at their para position with respect to the nitrogen atom[1]. In the second compound (ACz), the carbazole units are connected through ethynylene groups[2]. For this study, Raman and UV-Vis absorption spectroscopies have been used in combination with theoretical calculations based on the density functional theory (DFT). In addition, the two studied compounds have been implemented in organic field-effect transistors (OFETs), to assess their potential as active materials in organic electronics. Overall, the inclusion of ethynylene groups as π-conjugated spacers is found to be a good strategy to improve the electronic delocalization in macrocycles.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Investigation of the charge-transport and optoelectronic properties of carbazole-based macrocycles

Molecular systems have proven to be efficient active materials in electronics, being possible alternatives to the inorganic semiconductors used nowadays in electronic devices. In this project, an experimental and theoretical study of two carbazole-based macrocycles is presented (Figure 1). Specifically, we investigated the impact of the inclusion of acetylene groups on the electronic and molecular structures of these macrocycles, as well as their potential as charge transporting materials. The first studied compound (Cz) is composed by four carbazole groups linked at their para position with respect to the nitrogen atom1.In the second compound (ACz), the carbazole units are connected through ethynylene groups2. For this study, Raman and UV-Vis absorption spectroscopies have been used in combination with theoretical calculations based on the density functional theory (DFT). In addition, the two studied compounds have been implemented in organic field-effect transistors (OFETs), to assess their potential as active materials in organic electronics. Overall, the inclusion of ethynylene groups as π-conjugated spacers is found to be a good strategy to improve the electronic delocalization in macrocycles.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Styrene Purification by Guest-Induced Restructuring of Pillar[6]arene

The separation of styrene (St) and ethylbenzene (EB) mixtures is important in the chemical industry. Traditionally, this is done using energy-intensive vacuum distillation columns. Adsorptive separation is an alternative approach. Here, we explore the St and EB adsorption selectivity of two pillar-shaped macrocyclic pillar[n]arenes (EtP5 and EtP6; n 5 and 6). Both crystalline and amorphous EtP6 can capture St from a St-EB mixture with remarkably high selectivity. We show that EtP6 can be used to separate St from a 50:50 v/v St:EB mixture, yielding in a single adsorption cycle St with a purity of > 99 %. Single crystal structures, powder X-ray diffraction patterns and molecular simulations all suggest that this selectivity is due to a guest-induced structural change in EtP6 rather than a simple cavity/pore size effect. This restructuring means that the material ‘self-heals’ upon each recrystallization, and St separation can be carried out over multiple cycles with no loss of performance

Hierarchical self-assembled photo-responsive tubisomes from cyclic peptide-bridged amphiphilic block copolymer

Typically, the morphologies of the self-assembled nanostructures from block copolymers are limited to spherical micelles, wormlike micelles and vesicles. Herein, we report a new generation of materials with unique shape and structures, cylindrical soft matter particles (tubisomes), obtained from the hierarchical self-assembly of cyclic peptide-bridged amphiphilic diblock copolymers. Additionally, the capacity of obtained photo-responsive tubisomes as potential drug carriers is evaluated. The supramolecular tubisomes described here paves an alternative way for fabricating polymeric tubular structures, and will expand the toolbox for the rational design of functional hierarchical nanostructures

Near-Ideal Xylene Selectivity in Adaptive Molecular Pillar[n]arene Crystals

The energy-efficient separation of alkylaromatic compounds is a major industrial sustainability challenge. The use of selectively porous extended frameworks, such as zeolites or metal–organic frameworks, is one solution to this problem. Here, we studied a flexible molecular material, perethylated pillar[n]arene crystals (n = 5, 6), which can be used to separate C8 alkylaromatic compounds. Pillar[6]arene is shown to separate para-xylene from its structural isomers, meta-xylene and ortho-xylene, with 90% specificity in the solid state. Selectivity is an intrinsic property of the pillar[6]arene host, with the flexible pillar[6]arene cavities adapting during adsorption thus enabling preferential adsorption of para-xylene in the solid state. The flexibility of pillar[6]arene as a solid sorbent is rationalized using molecular conformer searches and crystal structure prediction (CSP) combined with comprehensive characterization by X-ray diffraction and 13C solid state NMR spectroscopy. The CSP study, which takes into account the structural variability of pillar[6]arene, breaks new ground in its own right and showcases the feasibility of applying CSP methods to understand and ultimately to predict the behaviour of soft, adaptive molecular crystals

Drug-initiated poly(thiocitc acid) polymer incorporating host-guest interaction for cancer combination chemotherapy

Summary: Combination chemotherapy has shown considerable promise for cancer therapy. However, the hydrophobicity of chemotherapeutic agents and the difficulties of precise drug co-administration severely hinder the development of combination chemotherapy. Herein, we develop a polymeric drug delivery system (D-PTA-CD) to provide robust loading capacity, glutathione-responsive drug release, and precise combination therapy. The vehicle is prepared based on poly(thioctic acid) (PTA) polymers using DM1, a chemotherapeutic agent, as the initiator to endow the vehicle with cancer-inhibiting activity. β-cyclodextrins are incorporated into the side chains to enhance drug loading capacity via host-guest interactions. Attributing to the sufficient disulfide bond on the backbone, D-PTA-CD exhibits accelerated drug release triggered by elevated glutathione levels. Doxorubicin (DOX) and camptothecin (CPT) are encapsulated by D-PTA-CD to afford the combination chemotherapy nanoparticles (NP), DOX-NP, and CPT-NP, respectively, which exhibit significant synergetic anti-cancer effects, highlighting the enormous potential of D-PTA-CD as a versatile drug delivery platform for cancer combination chemotherapy