Porous Supramolecular Networks Research Articles

J‐Type Self‐Assembled Supramolecular Polymers for High‐Performance and Fast‐Response n‐Type Organic Electrochemical Transistors

AbstractTo date, high‐performance organic electrochemical transistors (OECTs) are almost all based on conjugated polymers. Small molecules can be synthesized with high purity without batch‐to‐batch variations. However, small molecules require highly crystalline films and good molecular packings to achieve high charge carrier mobilities. Such features make their films unsuitable for ion diffusion or make their molecular packing distorted due to ion diffusion, resulting in poor ion/charge carrier transport properties and slow response speed. Herein, it is proposed to construct small‐molecule‐based supramolecular polymers to address these issues. A molecule, namely TDPP‐RD‐G7 is designed, which exhibits J‐type self‐assembling behaviors and can form supramolecular polymers in solution and conjugated‐polymer‐like networks in solid state. More importantly, the porous supramolecular polymer networks allow fast ion diffusion and greatly increase the device response speeds. As a result, the TDPP‐RD‐G7 exhibits record fast response speeds (τon/τoff) of 10.5/0.32 ms with high figure‐of‐merit (µC*) of 5.88 F cm−1 V−1 s−1 in small‐molecule OECTs. This work reveals the possible reasons that hinder the response speeds in small‐molecule OECTs and demonstrates a new “supramolecular polymer” approach to high‐performance and fast‐response small‐molecule‐based OECTs.

Spontaneous and scanning-assisted desorption-adsorption dynamics in porous supramolecular networks at the solution-solid interface.

Self-assembled molecular networks (SAMNs) are formed by the spontaneous assembly of molecules on surfaces. On conductive atomically flat surfaces, and also at the liquid-solid interface, scanning tunneling microscopy (STM) can follow their growth dynamics. Desorption and adsorption dynamics are difficult to probe through the liquid-solid interface. Porous molecular networks are of particular interest because they may act as platforms for sensing and host-guest chemistry. Very little is known though about their stability, particularly in a liquid environment. To this end, we have investigated the desorption/adsorption dynamics of supramolecular porous monolayers of alkoxylated dehydrobenzo[12]annulene (DBA) derivatives at the interface between highly oriented pyrolytic graphite, the substrate, and 1-phenyloctane, the liquid. To trace the dynamics, structurally analogous chiral DBA derivatives were used as marker molecules, which co-assemble with the achiral ones forming the supramolecular network. This approach reveals the time scales of the adsorption/desorption dynamics, the significance of temperature, and the important role of the STM tip in inducing dynamics.

Superior Electromagnetic Shielding and Mechanical Buffering Achieved by Alternating Conductive and Porous Supramolecular Networks

The development of electromagnetic interference (EMI) shielding materials with excellent EMI shielding effectiveness (SE), and superior mechanical performance is of great importance in daily life and in the military, where they are used for intelligent transportation systems and ammunition. Generally, shielding performances can be realized via reflection loss and absorption loss. However, it is still a challenge to enhance these two kinds of electromagnetic wave loss in the same material at the same time to achieve ideal shielding performance. Herein, a flexible Ag NDs/CNT@PC/Ni‐9 film composed of five conductive layers and four porous layers is prepared by alternating Ag NDs/CNT layers and PC/Ni layers through self‐assembly. The obtained film with a thickness of 890 μm exhibits a remarkable SE performance of 138 dB in the X‐band. Additionally, with a series of continuous volcanic mechanical impacts (>10 000 g), the maximum instantaneous acceleration is decreased by 30.02% due to the buffering of the film, which constitutes a much‐improved energy absorption cushion relative to that of traditional buffering materials, such as foam metal and rubber. A material integrated with strong EMI shielding and high mechanical shock resistance is designed, which provides an effective strategy for the development of functional materials for extreme environments.

A biomass-assembled macro/meso-porous nano-scavenger for Hg ion trapping

Simple self-assembling functional biomass to fabricate porous supramolecular networks for efficient removal of Hg ions.

Construction of host-guest supramolecular bilayer networks at liquid/solid interfaces by scanning tunneling microscopy

The monolayer self-assembled porous supramolecular networks of p-terphenyl-3,5,3′′,5′′-tetra-carboxylic acid (TPTC) that stabilized by intermolecular hydrogen bonding between four carboxyl groups at nonanoic acid/graphite interface were constructed. Scanning tunneling microscopy (STM) demonstrates that the guest molecules coronene (COR) adsorption in the pores of TPTC monolayer network. Furthermore, TPTC molecules can form the bilayer supramolecular framework and the trapping of COR guest molecules in both layers.

Porous Cd2+ Supramolecular Network Constructed from 2,3,5,6-Pyridinetetracarboxylhydrazide

Under the hydrothermal conditions, the simple self-assembly between Cd2+, 2,3,5,6-pyridinetetracarboxylic acid (L1′), and N2H4 created a L12−-based Cd2+ coordination polymer [Cd(L1)(N2H4)] · 2H2O (L12− = 2,3,5,6-pyridinetetracarboxylhydrazidate) 1. H2L1 derived from the in situ acylation of L1′ with N2H4. X-ray single-crystal diffraction analysis reveals that 1 possesses a 1-D chained structure co-bridged by L12− and N2H4, where a castellated CdO single-chain is observed. It is noteworthy that between the L12− molecules, two types of cyclic hydrogen-bonded synthons are found. Via these weak intermolecular interactions, 1 self-assembles into a 3-D porous supramolecular network (window size: 8 × 7 A2). The tetrahenuclear water clusters with a tetrahedral structure are observed in the pores.

Quinoline derivative containing monomeric and polymeric metal carboxylates: Synthesis, crystal structure and gas adsorption study over a 2D layered framework

A new supramolecular metal-carboxylate framework [Co(mqc)2]n (1), and another monomeric compound [Zn (mqc)2(H2O)] (2) (mqcH = 4-methoxy 2-quinolinecarboxylic acid) have been synthesized solvothermally and characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, UV–vis spectra, powdered X-ray diffraction (PXRD) and thermogravimetric analysis. Compound 1 is a 2D coordination polymer, extended to a 3D porous supramolecular network having void space in between 2D layers. Compound 1 exhibits gas uptake capacity of N2, H2, CO2 and CH4 like small gas molecules in which moderately high uptake of H2 and CO2 takes place among the 2D MOFs. While the Zn variety, compound 2 features a one-dimensional chain like structure through strong intermolecular hydrogen-bonding.

Novel porous supramolecular networks: synthesis, characterization and sorption properties

Novel porous supramolecular networks: synthesis, characterization and sorption properties

Guest exchange in soft porous supramolecular network

Guest exchange in soft porous supramolecular network

Directed Organization of Platinum Nanocrystals through Organic Supramolecular Nanoporous Templates.

We propose a novel approach to trap 2 nm Pt nanocrystals using nanoporous two-dimensional supramolecular networks for cavity-confined host-guest recognition process. This will be achieved by taking advantage of two features of supramolecular self-assembly at surfaces: First, its capability to allow the formation of complex 2D architectures, more particularly, nanoporous networks, through noncovalent interactions between organic molecular building-blocks; second, the ability of the nanopores to selectively host and immobilize a large variety of guest species. In this paper, for the first time, we will use isotropic honeycomb networks and anisotropic linear porous supramolecular networks to host 2 nm Pt nanocrystals.

Solid state reconstructive phase transition from porous supramolecular network to porous coordination polymer

Herein, we present an exceptional structural transformation from a porous supramolecular network to a porous coordination polymer. The transformation involves a change of interpenetrating dimensionality from 6-fold to 5-fold. Simultaneously, the spin state of nickel(ii) is altered from S = 0 to S = 1, which is concomitant with the formation of the Ni-O(carboxylate) coordination bonds.

Porous supramolecular networks constructed of one-dimensional metal-organic chains: carbon dioxide and iodine capture.

In search of porous materials for selective sorption and iodine inclusion, we have found two networks made of chains with a kink at the metal nodes held together by supramolecular interactions (H-bond and π···π stacking). The solvent can be removed and replaced reversibly without loss of crystallinity, as demonstrated by single-crystal-to-single-crystal crystallography. In contrast, iodine uptake degrades the crystallinity to amorphous, and it regains its crystalline state after removal of the iodine at 200 °C. Slight differences in behavior of the sorption and inclusion properties between the tetrahedral metal nodes, Zn and Co, are associated with the size of the nodes. An important feature is the extent of iodine that can be included between the chains that is doubled with temperature from 30 to 100 °C and exceeds the weight in mass of the compounds.

A supramolecular approach towards the construction of molecular salts using phosphonic acid and pyrazole

Systematic co-crystallization of a pyrazole analogue with various phosphonic acids resulted in robust supramolecular synthons between phosphonic acid and pyrazole, responsible for solid-state design. A series of phosphonic acids and methylenebis(3,5-dimethylpyrazole) (MBPz) has produced six molecular salts viz., [HPPA−·H2PPA·HMBPz+·MBPz] (1), [(HtBPA−)2·H2MBPz2+·EtOH] (2), [HPAA−·HMBPz+·MBPz·MeOH] (3), [HPPRA−·HMBPz+] (4), [H2EA2−·H2MBPz2+·S] (5) and [H3DPA−·(H2DPA2−)0.5·H2MBPz2+·(H2O)0.4] (6) where H2PPA = phenylphosphonic acid, H2PAA = phosphonoacetic acid, H2PPRA = 3-phosphonopropionic acid, H2tBPA = tert-butylphosphonic acid, H4EA = etidronic acid, H4DPA = [1,4-phenylenebis(methylene)]diphosphonic acid and S = squeezed solvent molecule. Different substituent(s) on the phosphonic acid influenced the conformation of the MBPz molecule, which in turn led to the formation of distinct supramolecular organic frameworks (SOFs) with an array of reliable synthons. Structural analyses revealed that both compounds 1 and 2 exhibited a layered structure but the parallel stacked sheets are displaced in the former salt as compared to the latter. Salts 4 and 5 exhibited a three-dimensional (3D) hydrogen bonded supramolecular network and 2D porous supramolecular network, respectively. On the other hand, salts 3 and 6 display an interpenetrated supramolecular network and host–guest assembly, respectively. Furthermore, the interaction energy was calculated theoretically by using the Density Functional Theory (DFT) level energy to evaluate the stability of the corresponding salt, which was further corroborated by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis.

Mutual interplay of non-covalent interactions in modulating the geometry of organic linkers in their salts

Two ion-pair compounds (Hhfipbb)2·(H2px2ampy) (1) and (H2pxph)·(4-Hptz)2 (2) have been synthesized, based on the ligands 4,4′-(hexafluoroisopropylidene)-bis(benzoic acid) (H2hfipbb), 1,4-bis(2-pyridylaminomethyl)benzene (px2ampy), p-xylylenediphosphonic acid (H4pxph) and (5-(4-pyridyl) tetrazole) (4-ptz). Both the compounds 1 and 2 are characterized by routine elemental analyses, IR-, thermogravimetric studies and unambiguously characterized by single crystal X-ray crystallography. The mutual supramolecular interactions, exhibited by the individual ligands in the organic salts, modulate their geometries to form higher dimensional supramolecular architectures in the crystals of organic salts 1 and 2. In compound 1, the di-cation H2px2ampy2+ modulates its potential hydrogen donor sites in a cis conformation to form a R22(8) hetero synthon with carboxylate oxygen atoms of singly deprotonated Hhfipbb1− anion and thereby restricts the twisting between two benzene rings in the Hhfipbb1− skeleton to form 3D intricate supramolecular architecture. The trans-conformations of H4pxph (compound 2) forms 1D chain through R22(8) homo synthons, which extends to a 3D porous supramolecular network through interactions with 4-Hptz+ cations (by twisting them). The ion components, that are present in both compounds, modulate their geometry from their classical geometries, displayed by them in the metal coordination architectures and inorganic salts.

Bimolecular porous supramolecular networks deposited from solution on layered materials: graphite, boron nitride and molybdenum disulphide.

A two-dimensional porous network formed from perylene tetracarboxylic diimide (PTCDI) and melamine may be deposited from solution on the surfaces of highly oriented pyrolytic graphite (HOPG), hexagonal boron nitride (hBN) and molybdenum disulphide (MoS2). Images acquired using high resolution atomic force microscopy (AFM) operating under ambient conditions have revealed that the network forms extended ordered monolayers (>1 μm(2)) on HOPG and hBN whereas on MoS2 much smaller islands are observed.

Structural diversity of two novel complexes of Co(II) with bis-triazole ligand: From one-dimensional chain to two-dimensional porous network

Using two novel bis-triazole ligands, 2,6-bis(1,2,4-triazole-4-yl)pyridine (L1) and 1,6-bis(1,2,4-triazole-1-yl)hexane (L2), one novel one-dimensional (1D) chain polymer [Co(NCS)2(L1)2] n (I) and one two-dimensional (2D) coordination polymer [Co(NCS)2(L2)2] n (II) have been synthesized and structurally characterized. The crystal crystallizes in the triclinic system for I, space group $$P\bar 1$$ , a = 7.879(6), b = 8.830(7), c = 9.837(8)A, α = 70.230(11)°, β = 115.474(6)°, γ = 85.591(12)°, Z = 1. The crystal crystallizes in the mo-noclinic system for II, space group $$P\bar 1$$ , a = 7.879(6), b = 8.830(7), c = 9.837(8) α = 70.230(11)°, β = 115.474(6)°, γ = 85.591(12)°, Z = 1. The structural diversity of these two new Co(II) complexes vary from 1D chain to 2D porous supramolecular network, which may be ascribed to ligand directing effects under similar synthetic conditions (L1 contains rigid pyridine spacers while L2 contains flexible hexane spacers).

Self-Assembled Air-Stable Supramolecular Porous Networks on Graphene

Functionalization and modification of graphene at the nanometer scale is desirable for many applications. Supramolecular assembly offers an attractive approach in this regard, as many organic molecules form well-defined patterns on surfaces such as graphite via physisorption. Here we show that ordered porous supramolecular networks with different pore sizes can be readily fabricated on different graphene substrates via self-assembly of dehydrobenzo[12]annulene (DBA) derivatives at the interface between graphene and an organic liquid. Molecular resolution scanning tunneling microscopy (STM) and atomic force microscopy (AFM) investigations reveal that the extended honeycomb networks are highly flexible and that they follow the topological features of the graphene surface without any discontinuity, irrespective of the step-edges present in the substrate underneath. We also demonstrate the stability of these networks under liquid as well as ambient air conditions. The robust yet flexible DBA network adsorbed on graphene surface is a unique platform for further functionalization and modification of graphene. Identical network formation irrespective of the substrate supporting the graphene layer and the level of surface roughness illustrates the versatility of these building blocks.

Unique Type of BF2‐Capped Tetraoxobenzene π‐Complexes of “Cp*M”: Novel Organometallic Backbones for the Self‐Assembly of Porous Networks

AbstractThe synthesis of two novel organometallic π complexes of a BF2‐capped tetraoxobenzene (TOB) of the general formulae [Cp*M‐η6‐{BF2‐TOB‐BF2}] (M = Ir, 2a; M = Rh, 2b) is reported together with their molecular structures ascertained by single‐crystal X‐ray diffraction studies. Complexes 2a and 2b are isostructural and show the formation of 3D porous supramolecular networks. Interestingly the supramolecular networks arise from the zwitterionic nature of 2a and 2b. Indeed, the individual molecules self‐assemble through the teamwork of dipolar H···F hydrogen and C···F halogen bonds, which leads to the formation of 3D networks with empty channels. These complexes hold promise for the design of a new class of porous materials with useful properties.

Syntheses, crystal structures, and electrochemical properties of two cobalt complexes constructed with benzene tricarboxylates and 2,5-bipyridyl-1,3,4-oxadiazole

Two new cobalt complexes based on benzene tricarboxylates 1,2,4-H3BTC (1,2,4-H3BTC = 1,2,4-benzenetricarboxylate) or 1,3,5-H3BTC (1,3,5-H3BTC = 1,3,5-benzenetricarboxylate), and the bent dipyridyl ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) or its 4-pyridyl N-donor analog (4-bpo), formulated as [Co(1,3,5-BTC)(4-bpo)(H2O)3]2[Co(H2O)6] · 10H2O (1) and [Co3(1,2,4-BTC)2(3-bpo)2(H2O)12] (2), have been hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction. Structure analysis reveals that 1 is a 3-D porous supramolecular network based on the 1-D polymer chain , in which discrete [Co(H2O)6]2+ units and lattice water molecules are dispersed. In 2, bridging 3-bpo and 1,2,4-BTC connect cobaltions to form a trinuclear cobalt unit. Adjacent trinuclear cobalt units are further linked by π–π stacking interactions and hydrogen-bonding interactions to form a 3-D supramolecular framework. Electrochemical properties of cobalt(II) compounds bulk-modified carbon paste electrodes (1-CPE and 2-CPE) have been studied.

Polymorphic porous supramolecular networks mediated by halogen bonds on Ag(111)

Intermolecular structures of porous two-dimensional supramolecular networks are studied using scanning tunnelling microscopy combined with density functional theory calculations. The local configurations of halogen bonds in polymorphic porous supramolecular networks are directly visualized in support of previous bulk crystal studies.