Triptycene-Based Polymers of Intrinsic Microporosity: Organic Materials That Can Be Tailored for Gas Adsorption

Tetramethoxy-bay-substituted perylene bisimides by copper-mediated cross-coupling

CuBr-mediated cross-coupling of 1,6,7,12-tetrabromo-perylene-3,4,9,10-tetracarboxylic acid ester or bis(dicarboximide) with NaOMe affords the respective tetramethoxy-perylene derivatives which are excellent green and red emitters.

Phthalazinone structure-based covalent triazine frameworks and their gas adsorption and separation properties

In this work, new classes of phthalazinone-based covalent triazine frameworks (PHCTFs) were prepared by ionothermal synthesis from two full rigid dicyano building blocks with rigid, thermostable and asymmetric N-heterocycle-containing structures.

Monodispersed ultramicroporous semi-cycloaliphatic polyimides for the highly efficient adsorption of CO2, H2and organic vapors

Monodispersed ultramicroporous semi-cycloaliphatic polyimides (sPIs) were synthesizedviasolution polycondensation and possess high uptakes for CO₂, H₂, aromatic and aliphatic vapors, exhibiting potential in gas storage and the recovery of toxic organic vapors.

The enhancement of chain rigidity and gas transport performance of polymers of intrinsic microporosity via intramolecular locking of the spiro-carbon

We present a new strategy to improve the rigidity of PIM-1 through the introduction of 8-membered ring locking into the flexible spiro-carbon pivot point to produce a more rigid interlocked polycyclic structure.

Hierarchical coassembly of DNA-triptycene hybrid molecular building blocks and zinc protoporphyrin IX

Herein, we describe the successful construction of composite DNA nanostructures by the self-assembly of complementary symmetrical 2,6,14-triptycenetripropiolic acid (TPA)-DNA building blocks and zinc protoporphyrin IX (Zn PpIX). DNA-organic molecule scaffolds for the composite DNA nanostructure were constructed through covalent conjugation of TPA with 5'-C12-amine-terminated modified single strand DNA (ssDNA) and its complementary strand. The repeated covalent conjugation of TPA with DNA was confirmed by using denaturing polyacrylamide gel electrophoresis (PAGE), reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). The biologically relevant photosensitizer Zn PpIX was used to direct the hybridization-mediated self-assembly of DNA-TPA molecular building blocks as well as a model guest molecule within the DNA-TPA supramolecular self-assembly. The formation of fiber-like composite DNA nanostructures was observed. Native PAGE, circular dichroism (CD) and atomic force microscopy (AFM) have been utilized for analyzing the formation of DNA nanofibers after the coassembly. Computational methods were applied to discern the theoretical dimension of the DNA-TPA molecular building block of the nanofibers. A notable change in photocatalytic efficiency of Zn PpIX was observed when it was inside the TPA-DNA scaffold. The significant increase in ROS generation by Zn PpIX when trapped in this biocompatible DNA-TPA hybrid nanofiber may be an effective tool to explore photodynamic therapy (PDT) applications as well as photocatalytic reactions.

New phenazine-containing ladder polymer of intrinsic microporosity from a spirobisindane-based AB-type monomer

A new solution-processable ladder polymer (PSBI-AB) of intrinsic microporosity with dibenzodioxane linkages and bis(phenazine) units was designed and synthesized by self-polymerization of an AB-type monomer containing both catechol and aromatic dichloride groups.

A unique 3D ultramicroporous triptycene-based polyimide framework for efficient gas sorption applications

A novel 3D ultramicroporous triptycene-based polyimide framework with high surface area (1050 m² g⁻¹) and high CO₂ sorption capacity (3.4 mmol g⁻¹ at 273 K and 1 bar), good CO₂/N₂ (45) and CO₂/CH₄ (9.6) selectivity was synthesized and characterized.

Crystal Structures of a Molecule Designed Not To Pack Tightly

Organic molecules of intrinsic microporosity (OMIMs) are structurally constructed to not pack tightly. Consequently, only weak interactions between OMIM molecules can occur, which is the reason that almost all OMIMs have been described and investigated in their amorphous states. For the same reason it is very difficult to grow single crystals of OMIMs for X-ray structural analysis. Here we describe four different polymorphs of an OMIM that was before only described in the amorphous state.

Highly Permeable Benzotriptycene-Based Polymer of Intrinsic Microporosity

A novel polymer of intrinsic microporosity (PIM) was prepared from a diaminobenzotriptycene monomer using a polymerization reaction based on Tröger's base formation. The polymer (PIM-BTrip-TB) demonstrated an apparent Brunauer, Emmet, and Teller (BET) surface area of 870 m² g^-1, good solubility in chloroform, excellent molecular mass, high inherent viscosity and provided robust thin films for gas permeability measurements. The polymer is highly permeable (e.g., PH₂ = 9980; PO₂ = 3290 Barrer) with moderate selectivity (e.g., PH₂/PN₂ = 11.0; PO₂/PN₂ = 3.6) so that its data lie over the 2008 Robeson upper bounds for the H₂/N₂, O₂/N₂, and H₂/CH₄ gas pairs and on the upper bound for CO₂/CH₄. On aging, the polymer demonstrates a drop in permeability, which is typical for ultrapermeable polymers, but with a significant increase in gas selectivities (e.g., PO₂ = 1170 Barrer; PO₂/PN₂ = 5.4).

Synthesis of Triphenylene-Based Triptycenes via Suzuki-Miyaura Cross-Coupling and Subsequent Scholl Reaction

A two-step method (Suzuki-Miyaura cross-coupling, followed by Scholl oxidation) to triphenylene-based triptycenes is described, rendering a variety of π-extended triptycenes accessible in high yields and without the necessity of column chromatography purification. The versatility of this reaction has been demonstrated in the synthesis of a supertriptycene in only four steps and high yields.

Microporous spiro-centered poly(benzimidazole) networks: preparation, characterization, and gas sorption properties

Three microporous spiro-centered poly(benzimidazole) networks were synthesized based on the condensation of di-/trialdehyde with 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′,6,6′-tetrone in refluxing glacial acetic acid containing ammonium acetate.

Energy-efficient hydrogen separation by AB-type ladder-polymer molecular sieves

Increases in hydrogen selectivity of more than 100% compared with the most selective ladder polymer of intrinsic microporosity (PIM) reported to date are achieved with self-polymerized A-B-type ladder monomers comprising rigid and three-dimensional 9,10-dialkyl-substituted triptycene moieties. The selectivities match those of materials commercially employed in hydrogen separation, but the gas permeabilities are 150-fold higher. This new polymer molecular sieve is also the most selective PIM for air separation.

Triptycene induced enhancement of membrane gas selectivity for microporous Tröger's base polymers

A highly gas permeable polymer with exceptional size selectivity is prepared by fusing triptycene units together via a poly-merization reaction involving Tröger's base formation. The extreme rigidity of this polymer of intrinsic microporosity (PIM-Trip-TB) facilitates gas permeability data that lie well above the benchmark 2008 Robeson upper bounds for the important O2 /N2 and H2 /N2 gas pairs.

Triptycene-based Organic Molecules of Intrinsic Microporosity

Four Organic Molecules of Intrinsic Microporosity (OMIMs) were prepared by fusing triptycene-based components to a biphenyl core. Due to their rigid molecular structures that cannot pack space efficiently, these OMIMs form amorphous materials with significant microporosity as demonstrated by apparent BET surface areas in the range of 515-702 m(2) g(-1). Bulky cyclic 1',2',3',4'-tetrahydro-1',1',4',4'-tetramethylbenzo units placed on the triptycene termini are especially efficient at enhancing microporosity.

Restricted access: on the nature of adsorption/desorption hysteresis in amorphous, microporous polymeric materials

The phenomenon of low-pressure adsorption/desorption hysteresis, which is commonly observed in microporous polymers, is investigated by detailed gas adsorption studies. Diffusional limitations by pore blocking effects, which arise as a consequence of the micropore morphology and connectivity, are discussed as the origin of the hysteresis rather than swelling effects, which have been suggested previously. Micropores with narrow openings, which cannot be filled easily, are expected to be present next to open pores. Those pores are termed restricted-access pores and are only filled in the course of the adsorption process as a consequence of the increasing solvation pressure exhibited from already filled micropores. As a consequence of the results presented here, it is suggested to use the desorption branch in addition to the adsorption branch for the extraction of the porosity characteristics, such as specific surface area, pore volume, and pore size distribution. The magnitude of the low-pressure hysteresis might hence give an idea of the micropore connectivity, which is important information for potential applications.

Catalysis by Covalent Organic Frameworks (COFs)

Porous covalent organic frameworks (COFs) are an emerging class of versatile materials. They provide novel possibilities for application as solid catalysts in heterogeneous catalysis due to their defined tailorable structures and surface chemistry, in combination with a high porosity. Thus, access to highly disperse catalytic centers is enabled and mass transport effects can be easily tuned. Catalytic active centers in COFs result from one of three different ways: (i) utilization of the porous frameworks as supports for metal nanoparticles or clusters with additional stabilization via coordination effects. (ii) Immobilization of molecular metal species within coordinating heteroatom moieties at well‐defined organic linkers, which is comparable to a heterogenization of homogeneous catalyst species. (iii) Intrinsic catalytic properties of metal‐free organic frameworks due to heteroatoms or defined functional groups especially in organocatalysis. In recent years many novel COF materials have been tested in various catalytic reactions proving their suitability as solid catalysts.

Microporous organic polymers with ketal linkages: synthesis, characterization, and gas sorption properties

A series of microporous organic polymers with ketal linkages were synthesized based on the condensation of aromatic acetyl monomers with pentaerythritol. Fourier transform infrared and solid-state cross-polarization/magic-angle-spinning (13)C NMR spectroscopy were utilized to confirm the ketal linkages of the resulting polymers. The morphology can be observed from scanning electron microscopy and transmission electron microscopy images. The materials possess Brunauer-Emmet-Teller specific surface area values ranging from 520 to 950 m(2) g(-1), and the highest hydrogen sorption capacity is up to 1.96 wt % (77 K and 1.0 bar), which is superior to that of most of microporous organic polymers. The facile and cost-effective preparation process and excellent gas sorption properties make these kinds of materials promising candidates for practical applications.