Rigid Framework Research Articles

Ultra-stable hollow nanotube conjugated microporous polymer incorporating fluorenyl moieties for Co-capture of PM and CO2

Conjugated microporous polymers have a highly delocalized π-π conjugated porous skeleton connected by covalent bonds, which can combine their excellent stability with high adsorption, in order to be applied to the study of co-capture of harmful particulate matter (PM) and carbon dioxide (CO2) under high temperature and high humidity conditions. In this paper, fluorene-based coupled conjugated microporous polymers (D-CMPs) with functionalized hollow nanotubes and abundant microporous structures were proposed. Through mechanism exploration and molecular electrostatic potential (MESP) calculation, the capture efficiency, adsorption capacity and selectivity of PM and CO2 in the waste gas stream of carbon-based combustion were analyzed. The results indicate that D-CMPs, with their rigid carbon-based π-conjugated framework, exhibit excellent tolerance under prolonged high-humidity conditions, with a capture efficiency exceeding 99.87% for PM0.3 and exceeding 99.99% for PM2.5. Meanwhile, based on its chemical/thermal stability, it can realize the recycling of adsorption-regeneration. On this basis, the "slip effect" induced by the open three-dimensional hierarchical porous structure of D-CMPs significantly enhances airflow dispersion and improves gas throughput (with a minimal permeation resistance of only 15 Pa). At a pressure of 1 bar and a temperature of 273.15 K, D-CMP-2 exhibited a CO2 adsorption capacity of up to 2.69 mmol g−1. The fitting results of three isothermal adsorption models demonstrate that D-CMPs exhibit an outstanding equilibrium selectivity towards CO2. Therefore, prior to the widespread adoption of low-carbon and clean energy technologies, porous solid materials exhibiting excellent structural stability, equilibrium selectivity, environmental tolerance, and high adsorption capacity emerge as optimal candidates for the treatment of industrial waste gases.

Covalent-Frameworked 2D Crown Ether with Chemical Multifunctionality.

Here, we present the synthesis and characterization of a novel 2D crystalline framework, named C2O, which mainly consists of carbon and oxygen in a 2:1 molar ratio and features crown ether holes in its skeletal structure. The covalent-frameworked 2D crown ether can be synthesized on a gram-scale and exhibits fine chemical stability in various environments, including acid, base, and different organic solvents. The C2O efficiently activates KI through the strong coordination of K+ with crown ether holes in a rigid framework, which enhances the nucleophilicity of I- and significantly improves its catalytic activity for CO2 fixation with epoxides. The presence of C2O with KI results in remarkable increases in CO2 conversion from 5.7% to 99.9% and from 2.9% to 74.2% for epichlorohydrin and allyl glycidyl ether, respectively. Moreover, C2O possesses both electrophilic and nucleophilic sites at the edge of its framework, allowing for the customization of physicochemical properties by a diverse range of chemical modifications. Specifically, incorporating allyl glycidyl ether (AGE) as an electrophile or ethoxyethylamine (EEA) as a nucleophile into C2O enables the synthesis of C2O-AGE or C2O-EEA, respectively. These modified frameworks exhibit improved conversions of 97.2% and 99.9% for CO2 fixation with allyl glycidyl ether, outperforming unmodified C2O showing a conversion of 74.2%. This newly developed scalable, durable, and customizable covalent framework holds tremendous potential for the design and preparation of outstanding materials with versatile functionalities, rendering them highly attractive for a wide range of applications.

STRUCTURAL AND ELECTRICAL PROPERTIES OF MONOCRYSTALLINE Ag7+xGexP1-xS6 (x = 0.75; 0.5) SOLID SOLUTIONS

Compounds of the argyrodite structure are considered to be promising functional materials due to their peculiarities. The functional parameters of these compounds are provided by the peculiarities of the crystal structure, namely the simultaneous coexistence of a mobile cationic sublattice within a rigid anionic framework. Such a crystal structure motif determines the formation of wide regions of solid solutions based on argyrodites and makes it possible to increase the values of the functional parameters of these phases within the homogeneity regions. This work presents the results of the study of the structural and electrical properties of Ag7+xGexP1-xS6 (x = 0.75; 0.5) solid solutions with an argyridite structure. Single-crystal samples of solid solutions of Ag7.75Ge0.75P0.25S6 and Ag7.5Ge0.5P0.5S6 were obtained by the method of directional crystallization from the melt in vacuum-sealed quartz ampoules. It was found that the solid solutions of Ag7+xGexP1-xS6 (x = 0.75; 0.5) crystallize in orthorhombic crystal system: SG Pna21, with lattice parameters: a = 15.093 Å, b = 7.462 Å, c = 10.571 Å (Ag7.75Ge0.75P0.25S6) and a = 15.023 Å, b = 7.450 Å, c = 10.545 Å (Ag7.5Ge0.5P0.5S6). The frequency and temperature dependence of the total electrical conductivity was studied by impedance spectroscopy. The total electrical conductivity of the investigated single crystals is Ag7.75Ge0.75P0.25S6 5.43×10–3 S/cm (0.199 eV) and Ag7.5Ge0.5P0.5S6 2.22×10–2 S/cm (0.152 eV) at a temperature of 25 °C.
 Keywords: argyrodites; single crystals; electrical conductivity; phase analysis.

Transparent self-cleaning coatings repellent to ultralow surface tension liquids in extreme environments

Self-cleaning coatings have been garnering significant attention for their ability to reduce surface pollution by repelling liquids. However, creating transparent self-cleaning coatings that effectively repel ultralow surface tension liquids in harsh environments, like extremely high or low temperature environments, remains a challenge. Here, a transparent omniphobic coating (PMAPOSS-co-PFMA) is reported to achieve the repellency of droplets with surface tensions down to 15.5 mN·m−1 (n-pentane), even at temperatures up to 160 °C and down to −70 °C. The coating is engineered by grafting fluoropolymer with fluoroalkyl side chains onto the rigid polyhedral oligomeric silsesquioxane framework. The fluoroalkyl side chains tend to crystallize on the coating's surface, resulting in its low surface tension (measured at 9.39 mN·m−1). The incorporation of the robust POSS significantly enhances the coating's chemical, mechanical, and thermal stability. Moreover, with low roughness (Ra = 1 nm), the coating has a light transmittance of 90.5 %, surpassing untreated glass by 3.2 %. Heated at 80 °C, the migration of the long-fluorinated polymer chains within the PMAPOSS-co-PFMA coating enables its self-healing properties upon damage. These results provide a new perspective to develop versatile self-cleaning omniphobic coatings suitable for practical applications in extreme environments, such as asphalt transport pipes operating in high-temperature conditions.

Arbiters of Ugliness: A Review of Strategies for Describing Offensive Archival Materials

As archivists increasingly concede that neutrality is impossible, we suggest that non-action is still action. It follows that to treat reasonably offensive records as any other record is to apply an interpretation that they are innocuous, unremarkable, and uncontroversial. Archivists may perceive the stakes of describing these materials as particularly high, but they lack a comprehensive set of descriptive strategies in consideration of interpretive ethics. As a result, existing practices are likely to be local or ad hoc. This research aims to identify and explore descriptive strategies archivists use which serve to construct (or concede) the meaning that certain historical materials are potentially offensive using a combination of literature review, evaluation of finding aids and descriptive metadata, and exploratory interviews with archivists and other memory institution professionals. Results supported the assumption that strategies are largely ad hoc practices and local norms influenced by a handful of culturally sensitive descriptive protocols; underscored that strategies are contextually implemented; and revealed practical and philosophical divisions between archivists working with largely offensive collections and those working with largely uncontroversial ones. These findings suggest that while a comprehensive set of descriptive strategies may support a community grappling with its professional legacy, there may be no strategy capable of reconciling matters of ethics and discoverability, and the highly contextual practices are incompatible with overly rigid frameworks.

A sunflower-pith-based robust and efficient evaporator with enclosed cellular structure and ultralow vaporization enthalpy for round-the-clock steam generation

Solar interfacial evaporation (SIE) is a promising method to generate freshwater from unconventional water resources. Using hydrogel materials to activate water molecules has been demonstrated as a facile way to achieve high SIE performance. However, as for hydrogel and hydrogel-analogous evaporators, there is a trade-off between SIE performance and mechanical property due to their high water content and porous structure. Herein, we demonstrate a low-cost and robust sunflower-pith-based hydrogel-like evaporator by simple dip-coating and soaking process. The rigid cellular framework and water encapsulated inside endow this evaporator with excellent compressive strength, which achieves 400.3 ± 64.1 KPa at compressive strain of 80 %. In the meantime, natural ultralow water vaporization enthalpy and ability to capture thermal energy from surroundings enable this evaporator to achieve an outstanding water evaporation rate of 3.39 kg·m−2·h−1 with an energy efficiency of 100.2 % under 1 sun. Moreover, this evaporator exhibits a potential for round-the-clock operation since its evaporation rate can reach 1.14 kg·m−2·h−1 in dark. After introducing artificial open channels, this evaporator shows remarkable stability and durability even for 20 wt% brine. This work provides a sustainable choice for efficient desalination and freshwater production, and offers a guideline for the bionic design of SIE materials.

1D and 2D coordination polymers with a new rigid chelating linker: diacetylenedisalicylic acid.

Diacetylenedisalicylic acid is a new rigid linker molecule, capable of forming strong chelate bonds with metal cations. Its monosubstituted salts with dimethylamine and sodium form 1D and 2D coordination polymers, whose structures were solved from single crystals, along with the dimethyl ester of diacetylenedisalicylic acid. The structure of the dimethyl ester is characterized by a dense co-facial π-stacking of molecules with a dominance of van der Waals interactions between the stacks. The angle between the stack direction and the butadiyne groups does not meet the Enkelmann criterion for polymerization in a crystal. In contrast to the dimethyl ester, both salts have a rigid framework with channels filled with disordered solvent molecules. Photoluminescence spectra of the acid and its dimethyl ester have been studied. Thermal analysis of the acid confirms its high thermal stability to 286°C. The acid and its dimethyl ester are prone to polymerization on further heating followed by 50-52% mass loss, forming an amorphous carbon residue at 1000°C.

Spin qubits of Cu(II) doped in Zn(II) metal-organic frameworks above microsecond phase memory time.

With the aim of creating Cu(II) spin qubits in a rigid metal-organic framework (MOF), this work demonstrates a doping of 5 %, 2 %, 1 %, and 0.1 % mol of Cu(II) ions into a perovskite-type MOF [CH6 N3 ][ZnII (HCOO)3 ]. The presence of dopant Cu(II) sites are confirmed with anisotropic g-factors (gx =2.07, gy =2.12, and gz =2.44) in the S=1/2 system by experimentally and theoretically. Magnetic dynamics indicate the occurrence of a slow magnetic relaxation via the direct and Raman processes under an applied field, with a relaxation time (τ) of 3.5 ms (5 % Cu), 9.2 ms (2 % Cu), and 15 ms (1 % Cu) at 1.8 K. Furthermore, pulse-ESR spectroscopy reveals spin qubit properties with a spin-spin relaxation (phase memory) time (T2 ) of 0.21 μs (2 %Cu), 0.39 μs (1 %Cu), and 3.0 μs (0.1 %Cu) at 10 K as well as Rabi oscillation between MS =±1/2 spin sublevels. T2 above microsecond is achieved for the first time in the Cu(II)-doped MOFs. It can be observed at submicrosecond around 50 K. These spin relaxations are very sensitive to the magnetic dipole interactions relating with cross-relaxation between the Cu(II) sites and can be tuned by adjusting the dopant concentration.

Investigating the Structure-property Relationships of Two Cd-based Hybrid Multifunctional Compounds with High Tc, Bright Fluorescence and Wide Band-gap.

Organic-inorganic hybrid multifunctional materials have shown significant application in lighting and sensor fields, owing to their prominent performance and diversity structures. Herein, we synthesized two multifunctional compounds: (propyl-quinuclidone)2 CdBr4 (1) and (F-butyl-quinuclidone)2 CdBr4 (2). By introducing light-emitting organic cation with flexible long chain, 1 and 2 exhibit excellent transition properties and bright blue-white fluorescence. Then, combine fluorescence lifetime and first-principal calculation, providing evidence for the electron transfer emission. Subsequently, investigated the impact of substituent carbon chain length (methyl to butyl), structural rigidity (C-C to C-F) and halide framework (Cl to I) on the fluorescence properties. Results indicate that Cd⋅⋅⋅Cd distance and structural rigidity play an important role in fluorescence. Overall, our research provides valuable insight and example for chemical modifications enhance compound performance.

A Reading of Friedrich A. Kittler’s Reading of E.T.A. Hoffmann’s “Der Goldene Topf” (The Golden Pot) in Aufschreibesysteme 1800/1900 (Discourse Networks 1800/1900)

Friedrich A. Kittler’s canonical Aufschreibesysteme 1800/1900 (Discourse Networks 1800/1900) threatened the very idea of the canonicity of German literature. Yet Kittler’s readings systematically dismiss, mishear, and distort foreign voices who resist and cannot easily fit into his rigid theoretical framework. This discursive strategy is most apparent in his formative reading of E.T.A. Hoffmann’s 1814 “Der Goldene Topf: Ein Märchen aus der neuen Zeit” (The Golden Pot: A Fairy Tale for the Modern Age). Despite its erasures and repressions of difference, his reading of this text has had a largely positive reception. A re-reading of his formative reading is thus long overdue. By closely analyzing Kittler’s interpretation of Hoffmann’s text, this article demonstrates that Kittler's expressed claim to challenge a canonical approach to German literature and his disruptions of disciplinary norms and behavioral conventions mask his fundamental affiliation with processes of canonization.

Polyoxometalate-based reticular materials for proton conduction: from rigid frameworks to flexible networks.

Proton conductors play a crucial role in energy and electronic technologies, thus attracting extensive research interest. Recently, reticular chemistry has propelled the development of reticular materials with framework or network structures, which can offer tunable proton transport pathways to achieve optimal conducting performance. Polyoxometalates (POMs), as a class of highly proton-conducting units, have been integrated into these reticular materials using various linkers. This leads to the creation of hybrid proton conductors with structures varying from rigid crystalline frameworks to flexible networks, showing adjustable proton transport behaviors and mechanical properties. This Frontier article highlights the advancements in POM-based reticular materials for proton conduction and provides insights for designing advanced proton conductors for practical applications.

Oligo-benzamide-based peptide mimicking tools for modulating biology.

The oligo-benzamide scaffold is a rigid organic framework that can hold 2-3 functional groups as O-alkyl substituents on its benzamide units, mirroring their natural arrangement in an α-helix. Oligo-benzamides demonstrated outstanding α-helix mimicry and can be readily synthesized by following high yielding and iterative reaction steps in both solution-phase and solid-phase. A number of oligo-benzamides have been designed to emulate α-helical peptide segments in biologically active proteins and showed strong protein binding, in turn effectively disrupting protein-protein interactions in vitro and in vivo. In this chapter, the design of oligo-benzamides for mimicking α-helices, efficient synthetic routes for producing them, and their biomedical studies showing remarkable potency in inhibiting protein functions are discussed.

An integrated "rigid-flexible" strategy by side chain engineering towards high ion-conduction cationic covalent organic framework electrolytes.

In recent years, solid-state lithium metal batteries (SSLMBs) have become a new development trend, and it has become a top priority to design solid-state electrolytes (SSEs) that can rapidly and stably transport lithium ions in a variety of climatic environments. In this work, an integrated "rigid-flexible" dual-functional strategy is proposed to develop a cationic covalent organic framework (EO-BIm-iCOF) with well-defined flexible oligo(ethylene oxide) (EO) chains as an SSE for SSLMBs. As expected, the synergistic effects of the rigid cationic framework and flexible EO chains not only promote the dissociation of LiTFSI salts, but also greatly improve the transport of lithium ions, which endows LITFSI@EO-BIm-iCOF SSEs with a high Li+ conductivity of 1.08 × 10-4 S cm-1 and ionic transference number of 0.69 at room temperature. Besides, the molecular dynamics (MD) simulations have also elucidated the diffusion and transport mechanism of lithium ions in LITFSI@EO-BIm-iCOF SSEs. Interestingly, the assembled SSLMBs wherein LiFePO4 is paired with LITFSI@EO-BIm-iCOF SSEs display decent electrochemical properties at higher and lower temperatures. This work provides a great development prospect for the application of cationic COFs in solid-state batteries.

Strong size sieving effect in a rigid oxalate-based metal-organic framework for selective lithium extraction.

An oxalate-based metal-organic framework Eu-C2O4 was synthesized at gram-scale and studied as a selective adsorbent for Li+ ions, and it exhibited high Li+/Na+ selectivity in aqueous solution. A detailed mechanism study revealed that the key was the well-matched chelating sites of the framework for Li+ ion extraction.

Exploring a prototype for cooperative structural phase transition in cobalt(II) spin crossover compounds.

The creation of magnetically switchable materials that concurrently incorporate spin crossover (SCO) and a structural phase transition (SPT) presents a significant challenge in materials science. In this study, we prepared four structurally related cobalt(II)-based SCO compounds: two one-dimensional (1D) chains of {[(enbzp)Co(μ-L)](ClO4)2·sol}n (L = bpee, sol = 2MeOH·H2O, 1; L = bpea, sol = none, 2; enbzp = N,N'-(ethane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine); bpee = 1,2-bis(4-pyridyl)ethylene; and bpea = 1,2-bis(4-pyridyl)ethane) and their discrete segments, [{(enbzp)Co}2(μ-L)](ClO4)4·2MeOH (L = bpee, 3; L = bpea, 4). In all of these complexes, each Co(II) center is equatorially chelated by the planar tetradentate ligand enbzp and connected to a chain or dinuclear structure through bpee or bpea ligands along its axial direction. All of the complexes, including their desolvated phases, displayed overall incomplete and gradual SCO properties. Interestingly, the desolvated phase of 1 exhibited an additional non-spin magnetic transition characterized by wide room-temperature hysteresis (>40 K), which was reversible and rate-dependent, showcasing the synergy between SCO and SPT manifested through slow kinetics. We discuss the possible reasons for the distinct features and our findings demonstrate that the combination of a rigid polymeric framework with flexible substituents holds promise for achieving synergy between SCO and SPT.

ПОВЕСТВОВАНИЯ О СМЕРТИ БОГОХУЛЬНИКОВ В ЕПАРХИАЛЬНЫХ ВЕДОМОСТЯХ КОНЦА XIX — НАЧАЛА XX ВЕКА В КОНТЕКСТЕ ИСТОРИИ ЭМОЦИЙ

The article examines the features of stories about the “punishment of God”, or stories about the “miraculous” death of blasphemers, published in Russian diocesan journals of the late 19th — early 20th century. The historiographic gap in this area determines the novelty of the work. In addition to the traditional methods of historical research, the research methodology was based on the model of the “emotional process” by N. Frijda and B. Mesquito, the concept of “public images of feeling” by K. Geertz (“emotional matrices” by A. L. Zorin) and B. Rosenwein’s concept of textual “emotional communities”. Narrative monotony of stories about the “punishment of God”, their rigid genre framework, their belonging to the community of authors and readers from the clergy, made it possible to single out stable emotional structures in them. Firstly, blasphemy is presented in the form of an “emotional” crime, the characteristic features of a “blasphemer” as a subject of emotions are highlighted: it is a source of destructive experiences, unable to control feelings that are destructive for him and harmful to others (anger, malice, hatred), prone to impious fun, bold. Secondly, a blasphemer is considered as an object of emotions of a religious “moralist”, in the role of which the author (narrator) of the story acted and, as it was supposed, the reader of the text should have acted: this is hostility towards the sinner, alienation from him, satisfaction with the disastrous outcome of his “crime”. Thirdly, the forms of expression of the key genre emotion — fear (horror) are investigated, a three-dimensional model of its analysis is proposed: fear of the victim of “God’s judgment”; fear of eyewitnesses of the “miracle”; fear of the author — commentator and publisher.

Approach for quality deep-ultraviolet nonlinear optical crystals via a substitution strategy of channel species in zeolite.

Exploring the connections between the ion substitution of a material, its crystal structure, and its performance in applications is a regular task in synthetic chemistry. However, there still remain major challenges in the substitution of polyanionic groups for single ions. Herein, a strategy of channel species substitution of single anions by polyanionic groups in a zeotype rigid framework to design a new deep-ultraviolet nonlinear zincophosphate, {[Li3Na3(SiF6)]Cs2}[(ZnPO4)6], and tune physicochemical properties was proposed.

The Impact of Sustainability Reporting Practices on Financial Performance from Power and Energy Sector Organisations in Sri Lanka

Sustainability reporting integrates the organisation's economic, environmental and social performance towards achieving better financial performance and has become a contemporary issue due to the absence of a precise model or a rigid regulatory framework in this arena. The main objective of this study is to examine the impact of sustainability reporting practices on the financial performance of power and energy sector organisations in Sri Lanka. Another objective of this study was to determine the level of sustainability reporting practices in power and energy sector organisations. Sustainability disclosures were measured using social, economic, and environmental sustainability initiatives, and the company performance was measured through Return on Assets (ROA) and Sales Growth (SG). This study was based on ten power and energy companies listed in CSE in Sri Lanka and Government corporations in the power and utility sectors. The sustainability disclosures in the annual reports of the selected companies for the past nine years (2012-2020) were analysed. Accordingly, the author derived a disclosure index from the Global Reporting Initiative (GRI) guidelines, which consist of 91 parameters to evaluate the content of the reports of organisations in the power and energy sector. The analysis of the study's data has been done by employing the panel data analysis research technique. Descriptive statistics have been used to assess the level of sustainability reporting, and correlation matrix and panel data analyses were used to determine the impact of sustainability reporting on financial performance in power and energy sector organisations in Sri Lanka. Based on the research findings of the study, it was concluded that there is a negative association between the level of sustainability reporting and Return on Assets (ROA) as well as Sales Growth (SG). Finally, sustainability reporting disclosure does not affect a firm’s financial performance (ROA and Sales Growth) in power and energy sector organisations in Sri Lanka. It is recommended that future research can be further improved by using mixed research methods.

AgInS2-Embedded Photocatalytic Membrane: Insights into the Excited State and Electron Transfer Dynamics.

Photocatalytic reactions at semiconductor nanocrystal surfaces are useful for synthesizing value-added chemicals using sunlight. Semiconductor nanocrystals dispersed in a rigid framework, such as polymer film, can mitigate issues such as aggregation, product separation, and other challenges that are usually encountered in suspensions or slurries. Using a cation exchange technique, we successfully embedded AgInS2 nanoparticles into a Nafion matrix, termed AgInS2-Nafion. This was achieved through a galvanic exchange between In and Ag in In2S3 present within the Nafion film, enabling an adjustable Ag:In ratio for optimized photophysical properties. As in the case of colloidal suspension, the AgInS2 particles embedded in Nafion exhibit a long absorption tail, a broad emission band with a large Stokes shift, and emission lifetimes extending into the microseconds that are characteristic of donor-acceptor pairs, DAP. Remediation of surface states with the treatment of 3-mercaptopropionic acid resulted in significant enhancement in the emission yield. Charge carrier generation through bandgap excitation as well as activation of DAP states which reside within the bandgap is probed through transient absorption spectroscopy. The photocatalytic activity of AgInS2-Nafion was probed by using thionine as an electron acceptor. The electron transfer rate constant from excited AgInS2 to thionine as observed from transient absorption spectroscopy was determined to be ∼6.3 × 1010 s-1. The design of a photoactive membrane offers new ways to carry out photocatalytic processes with greater selectivity.

Self-Healing Hydrogen-Bonded Organic Frameworks for Low-Concentration Ammonia Capture.

The self-healing behavior has been extensively used in intelligent sensing systems capable of molecular recognition. However, most rigid crystalline frameworks, once collapsed under external stimuli like pressure, heat, or vacuum, could hardly recover to their crystalline phases under ambient conditions. Here, we report the self-healing of a new microporous hydrogen-bonded organic framework, FDU-HOF-3 (FDU = Fudan University), for ammonia (NH3) capture and compared it with the established mesoporous HOF-101. With the introduction of low-concentration NH3 into the pores, the HOFs became disordered but were then simply heated under a vacuum to return to their original crystalline states after NH3 removal. Close characterizations revealed that the repeatable self-healing behavior of these HOFs was achieved due to the COOH-NH3 acid-base interactions accompanied by the breaking and regeneration of complementary COOH-COOH hydrogen bonds. FDU-HOF-3 showed a record-capturing capability for low-concentration NH3 (8.13 mmol/g at 25 mbar) among all HOFs and displayed a quick photocurrent decrease after exposure to 250 ppm NH3 for less than 10 s. These self-healing HOFs were used to capture and release NH3 for over 10 cycles without any decrease in the adsorption capacities.