Porous Polymers Based on Aryleneethynylene Building Blocks

Relationships Between Defectivity and Porosity in High Surface Area Porous Aromatic Frameworks

Porous aromatic framework (PAF) microporosity is known to be strongly dependent on synthetic approach but little is known about why certain reactions yield significantly and consistently more porous PAFs. This article explores the connections between synthetic pathway, PAF defectivity, and microporosity. Using a network disassembly strategy, we show that defectivity is highly dependent on synthetic approach and that more defective PAFs are associated with lower surface areas and pore volumes. This empirical association is corroborated through systematic introduction of defects to a modelPAF, which results in significant reduction of apparent surface area and pore volumes. Taken together, these data suggest that only highly efficient coupling reactions should be targeted for the synthesis of ultra-high surface area porous aromatic frameworks.

Ultramicroporous Organophosphorus Polymers via Self-Accelerating P-C Coupling Reactions: Kinetic Effects on Crosslinking Environments and Porous Structures

Porous organic polymers (POPs) have drawn significant attention in diverse applications. However, factors affecting the heterogeneous polymerization and porosity of POPs are still not well understood. Herein, we report a new strategy to construct porous organophosphorus polymers (POPPs) with high surface areas (1283 m²/g) and ultramicroporous structures (0.67 nm). The strategy harnesses an efficient transition-metal-catalyzed phosphorus-carbon (P-C) coupling reaction at the trigonal pyramidal P-center, which is distinct from the typical carbon-carbon coupling reaction utilized in the synthesis of POPs. As the first kinetic study on the coupling reaction of POPs, we uncovered a self-accelerating reaction characteristic, which is controlled by the choice of bases and catalysts. The self-accelerating characteristic of the P-C coupling reaction is beneficial for the high surface area and uniform ultramicroporosity of POPPs. The direct crosslinking of the P-centers allows ³¹P solid-state (ss)NMR experiments to unambiguously reveal the crosslinking environments of POPPs. Leveraging on the kinetic studies and ³¹P ssNMR studies, we were able to reveal the kinetic effects of the P-C coupling reaction on both the crosslinking environments and the porous structures of POPPs. Furthermore, our studies show that the CO₂ uptake capacity of POPPs is highly dependent on their porous structures. Overall, our studies paves the way to design new POPs with better controlled chemical and ultramicroporous structures, which have potential applications for CO₂ capture and separation.

Palladium-Catalyzed Decarbonylative Sonogashira Coupling of Terminal Alkynes with Carboxylic Acids

A direct decarbonylative Sonogashira coupling of terminal alkynes with carboxylic acids was achieved through palladium catalysis. This reaction did not use overstoichiometric oxidants, thus overcoming the homocoupling issue of terminal alkynes. Under the reaction conditions, a wide range of carboxylic acids including those bioactive ones could couple readily with various terminal alkynes, thus providing a relative general method for preparing internal alkynes.

Cross-Dehydrogenative Alkynylation: A Powerful Tool for the Synthesis of Internal Alkynes

Alkynes are among the most fundamentally important organic compounds and are widely used in synthetic chemistry, biochemistry, and materials science. Thus, the development of an efficient and sustainable method for the preparation of alkynes has been a central concern in organic synthesis. Cross-dehydrogenative coupling utilizing E-H and Z-H bonds in two different molecules can avoid the need for prefunctionalization of starting materials and has become one of the most straightforward methods for the construction of E-Z chemical bonds. This Review summarizes recent progress in the preparation of internal alkynes by cross-dehydrogenative coupling with terminal alkynes.

Synthesis and properties of porous polymers synthesized by Michael addition reactions of multi-functional acrylate, diamine, and dithiol compounds

Porous polymers have been synthesized by Michael addition reactions of multi-functional acrylate and diamine or dithiol compounds. Aza-Michael addition reaction of multi-functional acrylate, trimethylolpropane propoxylate triacrylate (TPT) and hexamethylene diamine (HDA) in dimethyl sulfoxide (DMSO) successfully yielded the porous polymer. The porous structure was characterized by connected globules or co-continuous structure, and could be controlled by the reaction conditions. Mechanical properties of the porous polymers were investigated by compression test. The porous polymers with co-continuous structure showed higher Young's modulus than those with connected globules. The porous polymer absorbed some organic solvents, especially CHCl₃. The porous polymer as prepared in DMSO state showed coloring induced by Christiansen filter effect depending on the reaction time and observation temperature. The thio-Michael addition reaction of TPT and 1,6-hexanedithiol (HDT) in DMSO using different base catalysts also yielded the porous polymer. The porous structure could be controlled by the catalysts amount when the reaction was initiated by a photo-base generator as the base catalyst. The present reaction systems make it possible to synthesize the porous polymers with simple process without phase separator.

Porous networks based on iron(ii) clathrochelate complexes

Microporous networks based on boronate ester-capped iron(ii) clathrochelate complexes are described. The networks were obtained by covalent cross-linking of tetrabrominated clathrochelate complexes via Suzuki-Miyaura polycross-coupling reactions with diboronic acids, or by Sonogashira-Hagihara polycross-coupling of clathrochelate complexes with terminal alkyne functions and 1,3,5-tribromobenzene. The networks display permanent porosity with apparent Brunauer-Emmett-Teller surface areas of up to SABET = 593 m2 g-1. A clathrochelate complex based on an enantiopure dioximato ligand was used to prepare chiral networks. One of these networks was shown to preferentially absorb d-tryptophan over l-tryptophan.

One-Pot Synthesis of Core–Shell Structured Metal–Organic Coordination Polymer Microspheres with a Hierarchical Microporous–Mesoporous–Macroporous Structure

New core–shell structured metal–organic coordination polymer (CP) microspheres with a hierarchical microporous–mesoporous–macroporous structure are synthesized by a one-pot template-free method. The ligand L with a Schiff-base functional group is obtained by reacting 3-hydroxy-4-aminobenzoic acid with para-benzaldehyde. The coordination polymer microspheres (Zn-L-CP) are obtained by mixing the ligand L and zinc nitrate hexahydrate together under hydrothermal conditions. The resultant coordination polymer microspheres with a core–shell structure are characterized by FT-IR and solid state NMR spectroscopy, transmission and scanning electron microscopy, and nitrogen adsorption–desorption measurements. The obtained Zn-L-CP microspheres are proved to be effective heterogeneous catalysts for the deacetylation reaction with the merits of easy recycling and stability. The yield is 96% when using methanol as solvent, and the yield can remain at 90% after seven cycles.

Yolk-Shell Polystyrene@Microporous Organic Network: A Smart Template with Thermally Disassemblable Yolk To Engineer Hollow MoS2/C Composites for High-Performance Supercapacitors

Yolk-shell-type polystyrene@microporous organic network (Y-PS@MON) materials were prepared by the Sonogashira coupling of tetra(4-ethynylphenyl)methane and 1,4-diiodobenzene on the surface of PS@SiO2 and by the etching of SiO2. The diameter of PS yolk spheres and the thickness of MON shells were 150 and ∼10 nm, respectively. The thickness of the void space between the PS yolk and the MON shell was ∼30 nm. Y-PS@MONs were used as templates for the synthesis of MoS2/C composite materials. Because of the microporosity of the MON shells and the void space between the yolk and the shell, MoS2 precursor compounds were efficiently incorporated into Y-PS@MONs. The heat treatment under argon resulted in the formation of hollow MoS2/C composites. The contents of MoS2 in the composites were systematically controlled by changing the amounts of precursor. MoS2/C with 58 wt % of MoS2 showed the best energy storage performance with a capacitance of 418 F/g at a 0.5 A/g current density as an electrode material of a coin cell supercapacitor, which is attributable to its hollow structure, high surface area, and the good distribution of the sliced MoS2 in the carbon matrix. Also, the MoS2/C-58 composite showed excellent retention of capacitances during 5000 cycles.

Poly(aryleneethynylene)s: Properties, Applications and Synthesis Through Alkyne Metathesis

Functional polymeric materials have seen their way into every facet of materials chemistry and engineering. In this review article, we focus on a promising class of polymers, poly(aryleneethynylene)s, by covering several of the numerous applications found thus far for these materials. Additionally, we survey the current synthetic strategies used to create these polymers, with a focus on the emerging technique of alkyne metathesis. An overview is presented of the most recent catalytic systems that support alkyne metathesis as well as the more useful alkyne metathesis reaction capable of synthesizing poly(aryleneethynylene)s.

Microporous organic polymers involving thiadiazolopyridine for high and selective uptake of greenhouse gases at low pressure

Thiadiazolopyridine-based microporous organic polymers were shown to exhibit a remarkably high uptake of CO₂ of 5.8 mmol g⁻¹ at 273 K and 1 bar.

Amine post-functionalized POSS-based porous polymers exhibiting simultaneously enhanced porosity and carbon dioxide adsorption properties

We provide a possibility for post-synthetic amine functionalization of porous polymers exhibiting enhanced CO₂ capacity and selectivity without compromising the porosity.

Structure control and photocatalytic performance of porous conjugated polymers based on perylene diimide

Perylene diimide-based n-type porous conjugated polymers were prepared and evaluated as photocatalysts for hydrogen production and pollutant degradation applications.

Microporous organic polymers based on tetraethynyl building blocks with N-functionalized pore surfaces: synthesis, porosity and carbon dioxide sorption

We have synthesized nitrogen-rich polymers by copolymerization of tetraethynyl monomers with tris(4-iodophenyl)amine or 4,4′-diiodoazobenzene. Azobenzene-based polymers exhibited excellent CO₂ adsorption selectivity against N₂.

Hexaphenylbenzene and hexabenzocoronene-based porous polymers for the adsorption of volatile organic compounds

Here we report the vapor adsorption properties of two novel hexaphenylbenzene and hexabenzocoronene-based porous polymers which display excellent affinity for organic compounds (up to 100 wt%) and selectivity over water (<1 wt%).

Facile synthesis of bowl-shaped nitrogen-doped carbon hollow particles templated by block copolymer “kippah vesicles” for high performance supercapacitors

This paper reports a simple self-assembly strategy towards bowl-shaped carbon-containing hollow particles for high volumetric capacitance supercapacitors, as well as an unprecedented potential application for block copolymer vesicles in energy storage.

Conjugated microporous polymers with dimensionality-controlled heterostructures for green energy devices

Dimensionality for conjugated micro-porous polymers (CMP-nD, n = 0, 1, 2) is proven to be of great importance for tailoring their photophysical properties. Moreover, CMP-nD can further be converted into boron and nitrogen co-doped porous carbons (nDBN, n = 0, 1, 2) with maintained 0D, 1D, and 2D nano-structures and highly efficient catalytic performance.

Pyridine-based poly(aryleneethynylene)s: a study on anionic side chain density and their influence on optical properties and metallochromicity

We report the Pd-catalyzed synthesis of six new water soluble, alternating poly(p-phenylene-ethynylene-p-pyridinylene-ethynylene) (abcb-alternating) copolymers and one poly(p-pyridinyleneethynylene).

Nitrogen-enriched hierarchically porous carbon materials fabricated by graphene aerogel templated Schiff-base chemistry for high performance electrochemical capacitors

This article presents a facile approach for synthesizing 3D nitrogen-enriched hierarchically porous carbon materials via graphene aerogel templated Schiff-base chemistry.

Poly(aryleneethynylene)s (PAE) as paradigmatic sensor cores

What you need to know about poly(aryleneethynylene)s as sensory materials. A tutorial of fundamental properties and new developments since 2009.

From Hyperbranched Polymer to Nanoscale CMP (NCMP): Improved Microscopic Porosity, Enhanced Light Harvesting, and Enabled Solution Processing into White-Emitting Dye@NCMP Films

A two-step polymerization combining miniemulsion and solvothermal techniques was applied to synthesize tetraphenylethene-based nanoscale conjugated microporous polymers (TPE-NCMP), which simultaneously possessed a large surface area (1214 m²/g) and a high aggregation-induced florescence quantum yield (58%). Immobilization of Nile Red within micropores of TPE-NCMPs constructed a light-harvesting composite with characteristics of intense photons acquisition and efficient energy migration. Homogenous NCMP-based films were fabricated by blending the dye-doped TPE-NCMPs with PVA. The fluorescence emission could be flexibly tuned by varying the dosage of dyes over the whole visible spectrum including a pure white light.