Organic Assemblies Research Articles

Ni/Co bimetallic organic framework nanosheet assemblies for high-performance electrochemical energy storage.

Nickel-cobalt organic framework (denoted as NiCo-MOF) nanosheet assemblies are prepared through a controllable one-pot hydrothermal synthesis procedure at 150 °C. The as-prepared samples are directly employed as electrode materials for electrochemical energy storage (EES), and exhibit excellent electrochemical performance. Among these samples, NiCo-MOF-1 displays a high capacity of 100.18 mA h g-1 (901.60 F g-1), and obtains a capacity retention of 81.00% over 3000 cycles at 5 A g-1. Likewise, in an aqueous device, NiCo-MOF-1//AC delivers a discharge capacity of 83.75 mA h g-1, and also exhibits a good cycling life (74.14% retention after 3000 cycles). These results demonstrate that multilayer NiCo-MOF nanosheet assemblies are potential electrode materials for EES.

Self-Assemblies Based on Traditional Medicine Berberine and Cinnamic Acid for Adhesion-Induced Inhibition Multidrug-Resistant Staphylococcus aureus.

S. aureus is resistant to various first-line antibiotics, and seeking multifarious strategies aimed at effective control of antibiotic-resistant behavior is urgently needed. Here, we report a two-component directed self-assembly mode: the phytochemicals berberine and cinnamic acid can directly self-assemble into nanoparticles (NPs) displaying good bacteriostastic activity. Compared with several first-line antibiotics, the obtained nanostructures have a better inhibitory effect on multidrug-resistant S. aureus (MRSA) and stronger ability for biofilm removal. These qualities are attributed to the fact that organic assemblies can first spontaneously adhere to the surface of the bacteria, infiltrate into the cell, and then lead to converging attack against MRSA; thereafter, multipath bactericidal mechanisms of NPs on MRSA are found by both transcriptomic analysis and quantitative Polymerase Chain Reaction analysis. Moreover, when combined with spectral data and single crystal X-ray diffraction, the NPs' self-assembly mechanism governed by hydrogen bonds and π-π stacking interactions is clearly elucidated. These non-covalent interactions induce the NPs' formation of butterfly-like one-dimensional self-assembled units and finally layered three-dimensional spatial configuration. In addition, biocompatibility tests show that the NPs are nonhemolytic with little toxicity in vitro and in vivo. This directed self-assembly mode can offer a new perspective toward the design of biocompatible antimicrobial nanomedicines for clinical translation.

PEDOT‐Cellulose Gas Diffusion Electrodes for Disposable Fuel Cells

AbstractThe mass implementation of renewable energy sources is limited by the lack of energy storage solutions operating on various timescales. Electrochemical technologies such as supercapacitors and batteries cannot handle long storage time because of self‐discharge issues. The combination of fuel storage technology and fuel cells is an attractive solution for long storage times. In that context, large‐scale fuel cell solutions are required for massive energy storage in cities, which leads to possible concepts such as low‐cost disposable fully organic membrane assemblies in fuel cells to avoid regeneration of expensive poisoned electrodes. Here, the formation of an organic gas diffusion electrode (GDE) fabricated by paper‐making production, combined with in situ polymerization is demonstrated for the first time. Cellulose is used as a 3D scaffold functionalized with poly(3,4‐ethylenedioxythiophene) (PEDOT) serving as both an electrical conductor and an electrocatalyst of high efficiency for the oxygen reduction reaction. The PEDOT‐cellulose porous GDE is implemented in a membrane assembly and demonstrated in a H2‐O2fuel cell. The demonstration of low‐cost material/manufacturing that is environmentally friendly is a paradigm shift in the development of fuel cells for a sustainable society.

Characterization of a silicon photo-multiplier array with summing board as a photo-multiplier tube replacement in organic scintillator assemblies

We report on the energy, timing, and pulse-shape discrimination performance of cylindrical 5.08 cm diameter × 5.08 cm thick and 7.62 cm diameter × 7.62 cm thick trans-stilbene crystals read out with the passively summed output of three different commercial silicon photo-multiplier arrays. Our results indicate that using the summed output of an 8 × 8 array of SiPMs provides performance competitive with photo-multiplier tubes for many neutron imaging and correlated particle measurements. For a 5.08 cm diameter × 5.08 cm thick crystal read out with SensL’s ArrayJ-60035_64P-PCB, which had the best overall properties, we measure the energy resolution as 17.8 ± 0.8% at 341 keVee (σ/E), the timing resolution in the 180–400 keVee range as 236 ± 61 ps (σ), and the pulse-shape discrimination figure-of-merit as 2.21 ± 0.03 in the 230–260 keVee energy range. For a 7.62 cm diameter × 7.62 cm thick crystal read out with SensL’s ArrayJ-60035_64P-PCB, we measure the energy resolution as 21.9 ± 2.3% at 341 keVee, the timing resolution in the 180–400 keVee range as 518 ± 42 ps, and the pulse-shape discrimination figure-of-merit as 1.49 ± 0.01 in the 230–260 keVee energy range. These results enable many scintillator-based instruments to enjoy the size, robustness, and power benefits of silicon photo-multiplier arrays as replacement for the photo-multiplier tubes that are predominantly used today.

Effects of CMC and Micelle Formation on the Removal of Sodium Benzoate or Sodium Stearate in a Sodium Aluminate Solution

Micelle formation over a critical micelle concentration (CMC) is related to the economic removal of organics in a sodium aluminate solution. In this research, removal of organics was investigated by adding activated alumina and red mud. The micelle formation of sodium benzoate and sodium stearate, together with enthalpy, Gibbs free energy and entropy, was discussed by detecting the surface tension. The removal rate of organics was > 21% with activated alumina or red mud in a concentrated sodium aluminate solution. Increasing benzoate (or stearate) concentration and elevating temperature decreased the surface tension. Furthermore, the concentrated sodium aluminate solution remarkably increased the cross-sectional headgroup area of sodium stearate compared with that of sodium benzoate and led to a strong depletion interaction and small organic assembly on the surface. The low CMC, large cross-sectional headgroup area and strong depletion interaction of micelles on the surface reduced the removal rate of organics in the sodium aluminate solution compared with that in water.

Elite governance of agritourism in the Philippines

Agritourism, particularly in the West, is imagined to be an organic assembly of family farms driven by urban middle class demand for new rural tourism experiences. In the developing world, it is increasingly advocated as a rural development tool with the promise of uplifting the lives of small farmers in sustainable ways. We challenge the assumption of the farm family at the helm of agritourism development, advocating instead for a more complex understanding of agritourism governance. We argue that agritourism involves multisectoral governance networks that are subject to the political economic realities of where these networks are situated. Thus, agritourism may endure the same social inequalities one would find in other rural development initiatives in the Global South. Agritourism in the Philippines is a case in point. Based on qualitative research, our findings show that agritourism in the Philippines is driven by a complex elite network involving state and private entities that are engaged in patronage politics. The uneven power dynamics associated with this governance arrangement create conditions that favor old and new landed elites and exclude marginalized small farmers, contradicting any official statement that promises inclusive rural development.

Enhanced Crystallization and Optimized Morphology of Perovskites Through Doping an Indium‐Based Metal–Organic Assembly: Achieving Significant Solar Cell Efficiency Enhancements

Perovskite crystallization and morphology are two essential factors to the photoelectric performances of perovskite solar cells (PSCs). A 3D metal–organic assembly [In2(phen)3Cl6]·CH3CN·2H2O (In2) is introduced for the first time into lead iodide precursor to modify the quality of a perovskite thin film through a two‐step sequential deposition method. As a result, both the lead iodide and perovskite exhibit improved crystallization and modified morphology. The optimized film presents less trap states and is thus in favor of the charge transfer as well as charge collection. Consequently, open circuit voltage (Voc) and fill factor obviously show enhancements from 0.99 to 1.04 V and from 0.66 to 0.71, respectively, yielding a significant increase in a power conversion efficiency from 15.41% to 17.15%. Meanwhile, the hydrophobic property of In2 can increase the moisture resistance of the perovskite, which offers a simple and effective method to improve the stability of PSCs.

Hydrogen-Bond-Assisted Symmetry Breaking in a Network of Chiral Metal-Organic Assemblies.

Herein we elucidate the interplay of chiral, chelate, solvent, and hydrogen-bonding information in the self-assembly of a series of new three-dimensional metal-organic architectures. Enantiopure ligands, each containing H-bond donors and acceptors, form different structures, depending on the ratio in which they are combined: enantiopure components form M4L4 assemblies, whereas racemic mixtures form M3L3 stacks. Chiral amplification within M3L3 enantiomers was observed when a 2:1 ratio of R and S subcomponent enantiomers was employed. Simply switching the solvent (from MeCN to MeOH) or chelating unit (from bidentate to tridentate) increased the diversity of structures that can be generated from these building blocks, leading to the selective formation of novel M2L2 and M3L2 assemblies. The addition of achiral ligand building blocks resulted in the formation of further structures: When an achiral subcomponent was combined with its R and S chiral congeners, a three-layer heteroleptic architecture was generated, with the achiral unit sitting at the top of the stack. When combined with the S enantiomer only, however, the achiral unit assembled in the center of the structure, thus demonstrating the selective placement of achiral units within chiral systems. Further sorting experiments revealed that combining R and S stereocenters within a single ligand led to diastereoselective product generation. These results show how geometric complementarity between different ligands impacts upon the degree of hydrogen-bonding within the assembly, stabilizing specific low-symmetry architectures from among many possible structural outcomes.

Remote control of charge transport and chiral induction along a DNA-metallohelicate.

Herein we present a new strategy to achieve chiral induction and redox switching along the backbone of metallohelicate architectures, wherein a DNA duplex directs the handedness and charge transport properties of a metal-organic assembly more than 60 bonds away (a distance of >10 nm). The quantitative and site-specific binding of copper(i) ions to DNA-templated coordination sites imparts enhanced thermodynamic stability to the assembly, while the DNA duplex transfers its natural right-handed helicity to the proximal and distal metal centers of the helicates. When copper(ii) ions are employed instead of copper(i) ions, spontaneous DNA-mediated reduction occurs, which we propose is followed by a slower change in coordination environment (from pentacoordinate CuII to tetrahedral CuI) to generate copper(i) helicates. We demonstrate that the reduction of the adjacent and distal bis-phenanthroline sites is dependent on their proximity to DNA guanine bases (which act as the electron source). The kinetics of helical charge transport can thus be tuned based on guanine-CuII separation, resulting in a sequence- and distance-dependent redox switch that transfers electronic information from DNA to multiple linearly-arranged metal centers.

Early Formation Pathways of Surfactant Micelle Directed Ultrasmall Silica Ring and Cage Structures.

By combining a surfactant, an organic pore expander, a silane, and poly(ethylene glycol) (PEG), we have observed the formation of a previously unknown set of ultrasmall silica structures in aqueous solutions. At appropriate concentrations of reagents, ∼2 nm primary silica clusters arrange around surfactant micelles to form ultrasmall silica rings, which can further evolve into cage-like structures. With increasing concentration, these rings line up into segmented worm-like one-dimensional (1D) structures, an effect that can be dramatically enhanced by PEG addition. PEG adsorbed 1D striped cylinders further arrange into higher order assemblies in the form of two-dimensional (2D) sheets or three-dimensional (3D) helical structures. Results provide insights into synergies between deformable noncovalent organic molecule assemblies and covalent inorganic network formation as well as early transformation pathways from spherical soft materials into 1D, 2D, and 3D silica solution structures, hallmarks of mesoporous silica materials formation. The ultrasmall silica ring and cage structures may prove useful in nanomedicine and other nanotechnology based applications.

Competing Roles of Crystallization and Degradation of a Metal-Organic Chalcogenolate Assembly under Biphasic Solvothermal Conditions.

Metal-organic chalcogenolate assemblies have attracted recent interest as ensemble nanomaterials that contain one- or two-dimensional inorganic nanostructures in a periodic array with supramolecular isolation provided by an associated organic ligand lattice. Biphasic immiscible synthesis at liquid-liquid interfaces is a convenient way to grow crystalline d10 metal-organic chalcogenolate assemblies. However, there has been little systematic study of the role of temperature on the nucleation, growth, and stability of hybrid chalcogenolates during biphasic synthesis. Silver benzeneselenolate, a robustly blue-luminescent, lamellar metal-organic chalcogenolate assembly, was crystallized at biphasic immiscible liquid-liquid interfaces under solvothermal conditions. A positive correlation between temperature and nucleation density was observed, and the luminescence was conserved in all examples of the crystalline phase. Applying solvothermal conditions to the biphasic synthesis generally increased the lateral dimensions of the crystals and strongly favored the crystalline phase of the compound. Although thin, well-formed crystals were observed within 1 h for interfacial reactions performed at high temperatures, degradation was observed in long duration growths resulting in aggregated silver metal. A study of the thermal stability of the material via thermogravimetric analysis revealed that the decomposition is likely a redox reaction reverting the compound to silver metal and diphenyl diselenide. In situ analysis of this degradation was performed by grazing-incidence wide-angle X-ray scattering, which confirmed that the decomposition occurs in a single step with no preceding changes to the structure of the material. This work demonstrates that biphasic solvothermal methods are amenable to the synthesis of hybrid metal-organic chalcogenolate assemblies and that temperature can be used to control product morphology and lateral crystal growth at the immiscible interface.

Visible-Light-Driven Photocatalytic Water Oxidation by a π-Conjugated Donor–Acceptor–Donor Chromophore/Catalyst Assembly

The organic chromophore 2,2′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(thiophene-3-carboxylic acid), T2-BTD, was prepared and investigated along with metal complex [Ru(bda)(pyP)2] (bda = 2,2′-bipyridine-6,6′-dicarboxylate; pyP = 3-(pyridine-4-yloxy)propyl)phosphonic acid), RuC, for light-driven water splitting in dye-sensitized photoelectrochemical cells. The resulting co-loaded organic chromophore plus catalyst surface assembly was evaluated by photocurrent transient measurement and direct O2 detection using a collector–generator cell. The complete SnO2/TiO2 core–shell-based photoanode exhibited an enhanced photocurrent (∼38 μA cm–2) compared to that with only the chromophore (∼24 μA cm–2). A modest Faradaic efficiency of 12% was recorded for O2 generation under 1 sun illumination in pH 3.9, 0.1 M acetate buffer solutions.

Is Life an Unavoidable Consequence of the Formation of the Universe? Investigating the Formation of Bio-Precursors and the Signature of Earth-Like Living Forms

TThis contribution to the Research Topic Imagining the Future of Astronomy and Space Sciences focuses on astrobiology and exoplanetary research. Understanding the origin of life is the main scientific challenge to this century and an interdisciplinary endeavor in itself. To that astronomy will contribute in three key issues. Firstly, by measuring the abundance of elements relevant to life in the Universe. Then by determining the preferred location for aminoacids and complex organic molecules assembly. Finally, by investigating the signatures of life in exoplanets. A new generation of facilities will need to be built to address these questions. The relevance of ultraviolet instrumentation for this purpose is highlighted in this short perspective.

Mithrene Is a Self-Assembling Robustly Blue Luminescent Metal–Organic Chalcogenolate Assembly for 2D Optoelectronic Applications

Crystalline metal–organic chalcogenolate assemblies are a class of semiconducting hybrid nanomaterials that consist of well-defined arrays of nanostructured inorganic coordination polymers with a supramolecular lattice of organic ligands. Growing crystals of periodic arrays of nanostructured hybrid chalcogenolates at biphasic liquid–liquid interfaces has been used to prepare semiconducting hybrid materials for potential applications in sensing, catalysis, mechanochemistry, organic light-emitting devices, and photovoltaics. However, a distinct lack of a systematic framework for quantifying the relationship between experimental parameters and the structure–function relationship of the prepared materials has been one of the largest hurdles for the emerging field of hybrid chalcogenolates and related hybrid coordination polymer systems. Here we examine the crystallization of silver benzeneselenolate, coined here as mithrene, at a toluene–water interface and demonstrate that silver ion concentration is the cri...

1,2,4,5-Benzenetetracarboxylic acid: a versatile hydrogen bonding template for controlling the regioselective topochemical synthesis of head-to-tail photodimers from stilbazole derivatives.

The crystal engineering of hydrogen bonded organic assemblies based on 1,2,4,5-benzenetetracarboxylic acid (H4bta) and stilbazole derivatives (1-10) is exploited to provide regio-controlled [2 + 2] photocycloadditions in the solid state. Single crystal X-ray diffraction analyses have revealed that all the arrays are built-up from the self-assembly of the (H2bta)2- dianion with two stilbazolium cations via O-HO- and N+-HO- charge-assisted H-bonding synthons: (4-Hstilbazolium+)2(H2bta2-). The dianion displays an interesting diversity of H-bonding motifs. Such structural flexibility allowed us to obtain four structure-types defined by the preferential formation of intramolecular or intermolecular hydrogen bonds between carboxylate-carboxylic groups. In these ionic assemblies two predominant structural H-bonding patterns were observed. The first pattern is characterised by the formation of intramolecular H-bonds in the dianion, leading to discrete assemblies based on ternary arrays. The second hydrogen pattern consists of 2-D hydrogen networks built-up from the self-assembly of anions via intermolecular H-bonds that are linked to the cations. Two additional examples, in which the dianion is self-assembled in two types of ribbons, were also observed. Another supramolecular feature predominant in all these arrays is the stacking of the cations in a head-to-tail fashion, which is controlled via cation-π interactions. These arrays are photoactive in the solid state upon UV-irradiation leading to the regioselective synthesis of rctt-cyclobutane head-to-tail-isomers in high to quantitative yield. In this work, the template tolerance either to steric or electronic effects by changing the number or positions of the supramolecular interactions exerted by distinctive functional groups was also explored. In addition, assemblies bearing 2-chloro (7 and 8) and 3-chloro-4-stilbazole (1 and 9) crystallize in two different crystalline forms, leading to novel examples of supramolecular isomers with similar solid state reactivity.

NIR-Emitting Alloyed CdTeSe QDs and Organic Dye Assemblies: A Nontoxic, Stable, and Efficient FRET System.

In the present work, we synthesize Near Infrared (NIR)-emitting alloyed mercaptopropionic acid (MPA)-capped CdTeSe quantum dots (QDs) in a single-step one-hour process, without the use of an inert atmosphere or any pyrophoric ligands. The quantum dots are water soluble, non-toxic, and highly photostable and have high quantum yields (QYs) up to 84%. The alloyed MPA-capped CdTeSe QDs exhibit a red-shifted emission, whose color can be tuned between visible and NIR regions (608–750 nm) by controlling the Te:Se molar ratio in the precursor mixtures and/or changing the time reaction. The MPA-capped QDs were characterized by UV-visible absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and zeta potential measurements. Photostability studies were performed by irradiating the QDs with a high-power xenon lamp. The ternary MPA-CdTeSe QDs showed greater photostability than the corresponding binary MPA-CdTe QDs. We report the Förster resonance energy transfer (FRET) from the MPA-capped CdTeSe QDs as energy donors and Cyanine5 NHS-ester (Cy5) dye as an energy acceptor with efficiency (E) up to 95%. The distance between the QDs and dye (r), the Förster distance (R0), and the binding constant (K) are reported. Additionally, cytocompatibility and cell internalization experiments conducted on human cancer cells (HeLa) cells revealed that alloyed MPA-capped CdTeSe QDs are more cytocompatible than MPA-capped CdTe QDs and are capable of ordering homogeneously all over the cytoplasm, which allows their use as potential safe, green donors for biological FRET applications.

The impact of nanoplastics on marine dissolved organic matter assembly

The environmental impact of nanoplastics (NPs) released into natural aquatic surroundings is an increasing concern. NPs are widely generated from our daily waste disposal and eventually reach the ocean, wherein consequent influences on aquatic environments remain unclear. In this regard, there are few studies investigating NP-related ecological impacts. Comprising one of Earth's major carbon pools, marine dissolved organic matter (DOM) serves an essential role in global carbon dynamics. The spontaneous assembly of DOM into particulate organic matter (POM) plays important roles in the marine carbon cycle, and is involved in hemostasis of various ecological communities. Here, we report that 10 ppb NPs (polystyrene/polymethyl methacrylate, 25 nm) appeared in a water column accelerate the kinetic assembly rate of DOM-POM transition. NPs with various characteristics show similar influences on DOM assembly, and seawater samples collected from disparate sites were used to further confirm this unanticipated phenomenon. In this study, we demonstrated that hydrophobic interactions contribute to the facilitation of NP-DOM aggregations. Our results illustrate that NPs alter DOM-POM assembly, which may potentiate unanticipated perturbation to the largest marine carbon pool. Such effects would warrant increased vigilance on current practices of plastic usage and disposal.

Self-Sorting of Metal-Organic Polymeric Assemblies in Gels: Selective Templation and Catalysis of Homodimers.

The development of generic strategy is essential for the construction of higher order supramolecular assemblies from the mixture of molecular components. Such higher order aggregations are possible through a self-sorting phenomenon, which is not well-explored in gel materials. Here, first examples of self-sorting in the coordination polymer (CP) based gels have been explored using three and four component systems. The self-sorting phenomenon has been monitored through a [2+2] photochemical reaction in the gel state and characterized by 1 H NMR, diffuse reflectance spectroscopy (DRS) and single crystal XRD analyses. Furthermore, AgI was shown to act as a supramolecular catalyst for the [2+2] photochemical reaction in gels.

Exploration of acoustical and dynamical properties of organic nanoparticle assemblies for increased sound insulation

Low-density highly porous solid monolithic macroscopic objects, consisting of hierarchical mesoporous three-dimensional assemblies of nanoparticles (aerogels), have been previously pursued mainly for their low thermal conductivity. Unlike classical aerogels based on silica being fragile materials, structural fragility issue has been addressed with materials referred to as polymer-crosslinked (or X-) aerogels. X-aerogels are low-density materials, yet their mechanical strengths have been significantly increased. This work explores ductile aerogels in potential uses as constrained damping layers integrated into classical wallboards for drastically increased sound transmission losses without significantly increasing the board thickness and weight. Their ductility and mechanical strength enables light-weight X-aerogel panels of less than 1 cm in thickness to be integrated into gypsum wallboards. This work has experimentally investigated the integrated wallboards to achieve significantly increased sound transmission loss without significantly increasing thickness and weight of integrated wallboard system. This paper discusses preliminary investigations on experimental methods to characterize broadband dynamic properties of X-aerogels for better understanding of its excellent effect in drastically increased sound transmission loss. Some preliminary test results carried out in chamber-based random-incident measurements demonstrate high potentials in building acoustics applications and beyond.

Key effect of robust π⋯π stacking on AIE performance for supramolecular indium(III)–organic assemblies and application in PMMA-doped hybrid material

Three new In(III)-based MOAs, namely [In(bipy)Cl3] (In1), [In(bipy)(CH3CH2OH)Cl3] (In2), [In(bipy)(H2O)Cl3]·CH3CN (In3), have been designed and synthesized based on the same nitrogen aromatic hydrocarbon building block but different solvent systems, and exhibit distinct fluorescence emission in the solid state. The key effect of robust π⋯π stacking synthon in dimers on the triggered AIE performance was well verified by subsequent single X-ray diffraction, theoretical calculation, liquid-phase fluorescence response and dynamic light scattering experiments in H2O:CH3CN mixed solvents with different water content. Moreover, excellent optical signal response and thermal stability of In3-based poly(methyl methacrylate) (PMMA) confirm its application potential as fluorescent film materials.