Extra Functional Groups Research Articles

Adipic acid-mediated hydrogen bonding network allocation for efficient proton conduction in water-stabilized lamellar MOF membranes

The poor water-stability and cross-layer proton transfer property pose a challenge to the lamellar metal–organic frameworks (MOFs) membrane when acting as a promising proton exchange membrane. Herein, we report an adipic acid-mediated strategy to improve the water-stability and the cross-layer proton conductivity of CuTCPP lamellar MOF membrane, which achieves a maximum power density and current density of 112.6 mW cm−2 and 424.4 mA cm−2, respectively. Adipic acid with extra functional groups (–PO3H2, –COOH) stably bridges the adjacent crystal layers via the terminal carboxylic acid anchoring Cu sites. In particular, the extra functional groups introduced into the adipic acid regulate the allocation of hydrogen bonding networks in an umbrella-shape around adipic acid with copper-porphyrin structures as external margin, enriching the coherence of hydrogen bonding network on the proton transport path. Benefiting from the regular pore structure of MOF, the optimized hydrogen bonding networks in adjacent crystal layers construct a more abundant through-plane transfer pathway. The resultant through-plane proton conductivities of CuTCPP-PO3H2/–COOH membranes are up to 108/89 mS cm−1 at 80 °C and 100 % RH, which is ∼ 6-fold higher than that of the pristine CuTCPP membrane (13 mS cm−1), with a conductivity attenuation of < 5 % during a humidity cycling test for 12 times.

Robust reduced graphene oxide-PDA/ZIF-8 aerogel composite for cyclic, high-capacity dye adsorption

The contamination of nanosized organic dyes in the water bodies is of great concern as it adversely affects the marine ecosystem and biodiversity, leading to water-borne ailments. In recent years, designing sustainable, high-performance, and cost-effective composite adsorbents embedded with functional adsorbents for wastewater treatment has attracted immense attention. In this work, a new composite aerogel (rGO-PDA/ZIF-8) was prepared via self-assembling graphene oxide (GO) flakes to form a three-dimensional (3D) structure with functional polydopamine (PDA). Then, ZIF-8 crystals were decorated on the porous aerogel structure via the in-situ crystallization method. PDA-modified rGO aerogel provided abundant useful functional groups, such as –OH, –COOH, and –NH–, on the surface, while the incorporation of ZIF-8 nanocrystals further endowed composite aerogels with higher surface area and extra functional groups for enhanced organic dye adsorption. Our results revealed that the composite aerogel exhibited not only ultrahigh adsorption towards methylene blue (MB) with a maximum adsorption capacity of 1045 ± 2.9 mg g−1 (with a maximum rejection rate of > 99 %) but also excellent recyclability with a slightly decreased adsorption capacity of 897 ± 26.9 mg g−1 and a stable removal efficiency of > 92 % even after 10 cycles of adsorption. To the best of our knowledge, the obtained adsorption capacity almost doubled the best-reported values at similar conditions in the literature. The excellent adsorption performance is owing to strong π–π and electrostatic attractions between the dye molecules and the hierarchical porous composite structures with functional PDA coating and ZIF-8 nano-adsorbents. Therefore, the new composite rGO-PDA/ZIF-8 aerogel composite has great potential in high-performance, cyclic small organic dye separation.

ECONOMICAL KNF-CHT-ALG BEADS FOR THE ADSORPTION OF PB (II) IONS IN WATER

The present study has been carried out using two types of beads which are CHT-ALG and KNF-CHT-ALG beads for the removal of Pb (II) ions. Among these two beads, KNF-CHT- ALG showed the highest adsorbent due to the availability of high surface roughness and large pores as examined in the FESEM analysis. Meanwhile, FTIR spectra has confirmed the existence of extra functional groups such as NH2, OH-, COO-, C-O, CO, and C-O-C in KNF-CHT-ALG which promoting Pb (II) ions to bind. The chitosan optimisation of the KNF-CHT-ALG beads also contributed to economical cost of the beads while maintaining the same performance of the metals removal. Clearly, from the research conducted, the KNF-CHT-ALG beads with ratio 0.6g:0.4g:0.6g for each material were found to be a suitable adsorbent for Pb (II) ions removal. The prime important is, the main part of the adsorbent which is KNF core is known to be a zero cost and abundantly available waste products that could serve as a practical means for metal ions adsorption such as at wastewater treatment plant. In the long term, this study is committed to targets for SDG 6 which is clean water and sanitation by 2030.

Influence of ligands within Al-based metal-organic frameworks for selective separation of methane from unconventional natural gas

Efficient CH4/N2 separation from unconventional natural gas is vital for both energy recycling and climate change control. Figuring out the reason for the disparity between ligands in the framework and CH4 is the crucial problem for developing adsorbents in PSA progress. In this study, a series of eco-friendly Al-based MOFs, including Al-CDC, Al-BDC, CAU-10, and MIL-160, were synthesized to investigate the influence of ligands on CH4 separation through experimental and theoretical analyses. The hydrothermal stability and water affinity of synthetic MOFs were explored through experimental characterization. The active adsorption sites and adsorption mechanisms were investigated via quantum calculation. The results manifested that the interactions between CH4 and MOFs materials were affected by the synergetic effects of pore structure and ligand polarities, and the disparities of ligands within MOFs determined the separation efficiency of CH4. Especially, the CH4 separation performance of Al-CDC with high sorbent selection (68.56), moderate isosteric adsorption heat for CH4 (26.3 kJ/mol), and low water affinity (0.1 g/g at 40% RH) was superior to most porous adsorbents, which was attributed to its nanosheet structure, proper polarity, reduced local steric hindrance, and extra functional groups. The analysis of active adsorption sites indicated that hydrophilic carboxyl groups and hydrophobic aromatic ring were the dominant CH4 adsorption sites for liner ligands and bent ligands, respectively. The methylene groups with saturated C–H bonds enhanced the wdV interaction between ligands and CH4, resulting in the highest binding energy of CH4 for Al-CDC. The results provided valuable guidance for the design and optimization of high-performance adsorbents for CH4 separation from unconventional natural gas.

Enhancement of Agrosoil Cd2+ Immobilization Efficiency through Incubation with Bamboo Sawdust/Rice Husk Biochar Blends: The Effect of Carbonization Temperature and Blending Ratio

ABSTRACT Thermal modification of blended feedstocks has recently gained popularity, due to its importance in improving biochar yield and features, such as pore structure and adding extra functional groups than pristine ones and thus improving adsorption effectiveness against a range of pollutants. In this study, the biochar made up of blended bamboo sawdust and rice husk has been investigated on its effectiveness on Cd2+ sorption processes controlling the accessibility and mobility of this metal in agro-soil. In a set of batch experiments, the effect of a 10% w/w biochar (carbonized at 400°C and 700°C) to soil ratio at various blending ratios (1:1, 1:3, and 3:1) on the adsorption and desorption characteristics of Cd2+ in agricultural clay soil incubated for 60 days was investigated. The adsorption kinetics and isotherms were also studied to examine adsorption mechanism at pH of 8, initial solute concentration 200 mg/L, ionic strength of 0.01 M (NaNO3), Contact time of 180 min, and adsorbent dosage of 0.1 g. For adsorption kinetics, pseudo-first order, pseudo-second order, elovich, and intra-particle diffusion models were fitted, while Langmuir, Freundlich, Temkin, and Dubinin Radushkevich models were fitted in isotherm study. According to the findings, increasing the carbonization temperature (400–700°C) boosted the effectiveness of cadmium removal substantially (70–96%), the best adsorption capacity of 130 mg/g was obtained at 700°C. Meanwhile, the removal efficiency of biochar blending ratios was not significantly different. Similarly, as the carbonization temperature was increased, the rate of Cd2+ adsorption increased dramatically, whereas the rate of Cd2+ desorption dropped. Langmuir isotherm adsorption model and Pseudo-second order kinetic model were found to fit best (R2 = 0.99) on isotherm and kinetics studies, respectively. It can be concluded that employing blended feedstock biochar could improve soil immobilization efficiency for Cd2+ in agricultural fields.

Cellulose-Based Materials for Water Remediation: Adsorption, Catalysis, and Antifouling

Cellulose-based materials have been advanced technologies that used in water remediation. They exhibit several advantages being the most abundant biopolymer in nature, high biocompatibility, and contain several functional groups. Cellulose can be prepared in several derivatives including nanomaterials such as cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidized cellulose nanofibrils (TOCNF). The presence of functional groups such as carboxylic and hydroxyls groups can be modified or grafted with organic moieties offering extra functional groups customizing for specific applications. These functional groups ensure the capability of cellulose biopolymers to be modified with nanoparticles such as metal-organic frameworks (MOFs), graphene oxide (GO), silver (Ag) nanoparticles, and zinc oxide (ZnO) nanoparticles. Thus, they can be applied for water remediation via removing water pollutants including heavy metal ions, organic dyes, drugs, and microbial species. Cellulose-based materials can be also used for removing microorganisms being active as membranes or antibacterial agents. They can proceed into various forms such as membranes, sheets, papers, foams, aerogels, and filters. This review summarized the applications of cellulose-based materials for water remediation via methods such as adsorption, catalysis, and antifouling. The high performance of cellulose-based materials as well as their simple processing methods ensure the high potential for water remediation.

P137 DEGRADATION RESISTANCE OF PVDF MESH IN VIVO IN COMPARISON TO PP MESH

Abstract Aim To researched the degradation resistance of PVDF mesh by comparing its morphological and chemical condition with PP mesh. Material and Methods PVDF and PP meshes analysed in this study were received from a previous animal experiment. To expose the surface of explanted meshes, a tissue removing method with protease was used and the result of this cleaning process was tested by X-ray Photoelectron Spectroscopy (XPS). The morphological condition of the mesh surface was compared using Scanning Electron Microscopy (SEM) and the chemical condition concerning degradation was analysed through Fourier Transform Infrared Spectroscopy (FTIR). The surface condition of PVDF mesh after 3-, 6-, 12- and 24-month implantation was illustrated and compared with two types of PP meshes. Results XPS revealed an absence of nitrogen, confirming the successful removal of tissue residues using protease. SEM results presented no notable morphological surface change of the PVDF mesh and progressive surface cracking processes over time of both types of PP meshes. FTIR spectra of the implanted PVDF meshes had no considerable difference from the spectrum of the pristine mesh, while FTIR spectra of both types of PP meshes had extra chemical functional groups increasing with implantation time, indicating progressive degradation. Conclusions PVDF mesh does not show signs of degradation up to 24 months after implantation while PP meshes progressively degrade with increasing time under the same conditions, which appears as worsening Environmental Stress Cracks. This study highlights the morphological and chemical stability of the PVDF mesh and demonstrates that the PVDF mesh is more resistant to degradation in comparison to the PP meshes.

Recent Advances and Perspectives on Expanding the Chemical Diversity of Lasso Peptides

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a growing family of natural products that exhibit a range of structures and bioactivities. Initially assembled from the twenty proteinogenic amino acids in a ribosome-dependent manner, RiPPs assume their peculiar bioactive structures through various post-translational modifications. The essential modifications representative of each subfamily of RiPP are performed on a precursor peptide by the so-called processing enzymes; however, various tailoring enzymes can also embellish the precursor peptide or processed peptide with additional functional groups. Lasso peptides are an interesting subfamily of RiPPs characterized by their unique lariat knot-like structure, wherein the C-terminal tail is inserted through a macrolactam ring fused by an isopeptide bond between the N-terminal amino group and an acidic side chain. Until recently, relatively few lasso peptides were found to be tailored with extra functional groups. Nevertheless, the development of new routes to diversify lasso peptides and thus introduce novel or enhanced biological, medicinally relevant, or catalytic properties is appealing. In this review, we highlight several strategies through which lasso peptides have been successfully modified and provide a brief overview of the latest findings on the tailoring of these peptides. We also propose future directions for lasso peptide tailoring as well as potential applications for these peptides in hybrid catalyst design.

Activation of 8–17 DNAzyme with extra functional group at conserved residues is related to catalytic metal ion

In 8–17 DNAzyme, the end loop A6G7C8 is a highly conserved motif. Here we reported an activation approach by specific chemical modifications on A6 and C8 for more efficient Ca2+-mediated reaction. The importance of the end loop was further highlighted and its critical conservation broken for more powerful catalysts.

Degradation resistance of PVDF mesh in vivo in comparison to PP mesh

Mesh implant has been applied in hernia repair and urogynecological reconstruction. Polypropylene (PP) is now the most widely used material for non-resorbable mesh implants. A degradation phenomenon of PP mesh, which is apparent on the mesh surface as cracking, flaking and peeling, was discovered in the 1990's. This phenomenon of mesh implant has drawn attention because of mesh-related litigations. Polyvinylidene fluoride (PVDF), due to its high biocompatible performance, has been used since 2003 as an alternative material for non-resorbable mesh implants. Till now, no such degradation phenomenon of PVDF mesh has been reported, although limited study on PVDF mesh is available.In this paper, we researched the degradation of PVDF meshes taking the degradation of PP mesh as a reference. The meshes analysed in this study were received from a previous animal experiment. To expose the surface of explanted meshes, a tissue removing method with protease was used and the result of this cleaning process was tested by X-ray Photoelectron Spectroscopy (XPS). The morphological condition of the mesh surface was compared using Scanning Electron Microscopy (SEM) and the chemical condition concerning degradation was analysed through Fourier Transform Infrared Spectroscopy (FTIR). The surface condition of PVDF mesh after 3-, 6-, 12- and 24-month implantation was illustrated and compared with two types of PP meshes.XPS revealed an absence of nitrogen, confirming the successful removal of tissue residues using protease. SEM results presented no notable morphological surface change of the PVDF mesh and progressive surface cracking processes over time of both types of PP meshes. FTIR spectra of the implanted PVDF meshes had no considerable difference from the spectrum of the pristine mesh, while FTIR spectra of both types of PP meshes had extra chemical functional groups (carbonyl (CO) and hydroxyl (-OH) groups) increasing with implantation time, indicating progressive degradation. This study highlights the morphological and chemical stability of the PVDF mesh and demonstrates that the PVDF mesh is more resistant to degradation in comparison to the other two types of PP meshes.

High-Performance PANI-Based Ammonia Gas Sensor Promoted by Surface Nanostructuralization

In the area of conductive polymer-based sensors, polyaniline (PANI) has been widely studied for NH3 gas detection and a lot of effort has been devoted to improving its sensing performance. In this work, PANI thin film was prepared by chemical oxidation polymerization and spinning coating approach. By further etching via reactive ion etching (RIE), a nanostructuralized PANI thin film was obtained. All of the morphology characterization, current-voltage (I–V) characteristics curves, and XPS analysis suggest that etching via RIE with O2 gas could not only effectively increase the sensitive area and chemical diffusion pathway but also introduce extra oxygen-containing functional groups to adsorb more NH3 molecules by hydrogen bond. The gas sensing performance of the PANI thin film sensor to NH3 was examined. When the concentration of NH3 gas increased from 3 ppm to 990 ppm, the response of pristine film-based PANI sensor increased from 1.07 to 1.48, while, the response of nanostructuralized film-based PANI sensor increased from 1.16 to 3.19. All the response, reproducibility, and selectivity to NH3 results showed that the PANI sensor of nanostructuralized thin film to NH3 was superior to the PANI sensor of pristine film. This work demonstrates a convenient and effective way that can be beneficially utilized for improving the gas sensing performance.

Functional stretching decreases knee joint loading in male athletes with gastroc--soleus tightness

Background and objective: Tightness of the gastroc--soleus muscle complex is one of the limiting factors of the ankle joint's range of motion (ROM) during daily activities. The aim of this study was to investigate the effectiveness of functional and extra-functional stretching of the gastrocnemius--soleus complex on knee joint loading in athletes with limited ankle dorsiflexion. Material and methods: In this cross-sectional study, 30 male athletes with gastrocnemius--soleus shortness were recruited and randomly divided into three equal-size groups of functional stretching, extra-functional stretching, and a control group. The extra-functional stretching group performed stretching exercises three times per day for eight weeks. The functional stretching group was instructed to change their gait pattern via increased heel strike during daily activities. Results: None of the stretching programs reduced the knee flexion angle in heel contact (p &gt; 0.05). The knee flexion angle was significantly increased in the stance phase in the functional group (p ≤ 0.05). Walking speed was increased significantly in the extra-functional group (p ≤ 0.05). The knee adductor moment and external rotation moment decreased significantly in the functional group (p ≤ 0.05). Conclusion: An eight-week functional stretching program in this study led to a reduction of knee loading in the frontal and horizontal planes in comparison to the extra-functional stretching group, demonstrating the effectiveness of functional stretching in improving knee joint biomechanics during walking.

Synthesis and characterization of novel functional hyperbranched polyamides from AB2 units: effect of extra functional groups

ABSTRACT Hyperbranched polymers (HPs), which in terms of structure may be compared to the branching structure of trees, are referred to as tree-like materials, but role of leave in these tree-like polymers is neglected and much attention has only been paid to their branches. In fact, functional groups in these polymers play a vital role the same as the role of leaves in trees. Therefore, in this paper, an attempt has been made to design and synthesize three AB2 monomers containing extra hydroxyl and nitro groups. The benefits of their presence in the structure of produced hyperbranched polyamides (HPs) are investigated. The polymer structure was characterized by FT-IR and 1 H NMR. The solubility of synthesized HPs was studied in different protic and aprotic solvents. The thermal stability of the prepared HPs was investigated by thermogravimetric and differential scanning calorimetric analyses. The photoluminescent properties of the HPs were also investigated.

Effect of Functional Groups of Metal-Organic Frameworks, Coated on Cotton, on Removal of Particulate Matters via Selective Interactions.

Currently, the contamination of air with particulate matters (PMs such as PM2.5 and PM10) is very severe, especially in Asian countries. Metal-organic frameworks (MOFs), with or without extra functional groups such as -NH2 and -NH-SO3H, were coated on conventional cotton to improve the efficiency of filters (composed of cotton fabric) in the removal of PMs from air. More importantly, the effect of the functional group of MOFs on the effective PM removal was analyzed quantitatively for the first time and could be interpreted via selective interactions. The removal efficiency was increased on the order: cotton < UiO-66/cotton < UiO-66-NH2/cotton < UiO-66-NH-SO3H/cotton, and the efficiency of the UiO-66-NH-SO3H-coated cotton was more than three times that of the pristine cotton. Moreover, the quality factor of cotton was more than doubled (or, 2.5-3 times) by UiO-66-NH-SO3H (only 20%) coating. The plausible mechanism for PM removal could be suggested based on the characterization of captured PM and introduced functional groups on MOFs. Based on the removal efficiency, pressure drop, and quality factor, coating of MOFs with functional groups, especially that are effective for charge separations (such as -SO3H), is one of the promising ways to improve the performance of PM filters. Moreover, the suggested strategy might be applied in capturing most of PMs composed of oxides, ammonium species, and carbons with polar outside.

Effect of molecular structures on static and dynamic compression properties of clay and amphiphilic clay/carbon nanofibers used as fillers in UHMWPE/composites for high‐energy‐impact loading

ABSTRACTThree different ultrahigh‐molecular‐weight polyethylene (UHMWPE)–clay nanocomposites (Muscovite, Cloisite 30B and amphiphilic clay/carbon nanofibers) were investigated with the nanocomposite nanomorphology studied before and after dynamic mechanical compressive tests at high strain rates. Their material structure and thermal properties were investigated using techniques such as step‐scan differential scanning calorimetry, split Hopkinson pressure bar, synchrotron small angle X‐ray scattering (SAXS), and dynamic mechanical analysis. Results were associated with morphological changes observed after deformation. chemical vapor deposition (CVD)‐modified nanocomposite, due to the molecular bonding and the extra functional groups, is designed with crystalline structures with fewer defects and higher stability. The increase in particulate/polymer interactions observed for the CVD‐modified material decreased the elongation in the quasi‐static test. However, the dynamic mechanical behavior contradicted the quasi‐static behavior because at very high strain rates there was not sufficient time for the interlamellar and intralamellar defect facilitated plastic flow and the material transitioned through the glassy state. The SAXS results show that deformation strongly induced changes in the UHMWPE and UHMWPE–clay nanocomposite morphology. SAXS indicates that CVD‐modified samples became more compact and dense, thus corroborating the formation of additional secondary bonds between structures and/or the carbon nanofibers alignment. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47094.

Graphene Oxide: A Modifiable Platform for Drug Delivery Imaging and Sensing

Due to its remarkable electronic properties, graphene has become a basis of many novel microelectronic devices. Its functional derivative, graphene oxide (GO), retains multiple properties of graphene, however, unlike graphene is water soluble and exhibits fluorescence over the functionalization-induced optical band gap. A large graphene platform with oxygen containing groups that can be easily functionalized with active agents or analyte binding sites makes GO attractive for biosensing and drug delivery applications. In addition, an intrinsic GO fluorescence in red/near-infrared region with reduced biological autofluorescence background provides a possibility of fluorescence imaging without the need in additional fluorophores. We explore these properties to develop a multifunctional delivery/imaging/sensing GO platform for cancer therapeutics. GO utilized in our work shows little to no apparent cytotoxicity in concentrations of up to 15 ug/mL. We optimize the size of the commercially available GO flakes via ultrasonic processing for the most efficient cellular internalization and use spectrally-resolved fluorescence imaging for in vitro detection in the spectral range specific to GO emission. Furthermore, ozone processing adding extra oxygen-containing functional groups to GO surface is used to spectrally adjust GO emission and enhance its intensity. Solution-based timed ozone treatment allows to blue shift and increase the intensity of the emission. Concomitantly, such processing provides the basis for versatile covalent functionalization of anticancer agents to the new addends on GO platform via synthetic route akin to peptide synthesis. Optimized GO moieties show efficient intracellular accumulation with a potential preference toward the cancer (MCF-7, HeLa) versus healthy (HEK-293) cells. A pH dependence of GO emission discovered in our previous work provides a sensing mechanism for the acidic environment of cancer cells. In this regard, spectrally-resolved fluorescence microscopy imaging suggests a more blue-shifted GO emission in healthy versus cancer cells. As a result we propose GO as efficient multifunctional candidate for in-vitro delivery of active agents, fluorescence imaging and sensing of cancerous environments.

Analysis of organic functional groups and some trace heavy metals in the settleable dust particles (dustfall) of Sulaimani City/KURDISTAN REGION-IRAQ.

Ambient settleable (dustfall) dust particles samples were collected during August 2009&#x0D; to March 2010 from 18 locations in Sulaimani City/KRI for qualitative analyzing by&#x0D; Fourier Transform Infrared (FTIR) spectroscopy instrument to characterize the common&#x0D; functional groups that existed in the samples. Furthermore, the samples were&#x0D; quantitatively analyzed for the heavy metals contents of; V, Co and As by Inductively&#x0D; Coupled Plasma-Optical Emission Spectroscopy ICP-OES. The collected samples&#x0D; involved samples of settleable dust particles from local source of the city (location 1 to&#x0D; 15) and settleable dust particles from dust storm event of 22 February, 2010 (location 16&#x0D; to18). The FTIR analysis identified the following functional groups; Sulfinate ester;&#x0D; Sulfoxide; Sulfate ion; P. Amine (bend.); Carbonyl; Thiol; Alkanes HC; P. Amine (str.);&#x0D; Bonded and free hydroxyl group in all the samples of (1 to 15) for the local source of&#x0D; dust particles except sample location number 6 which was free from sulfoxide, p. amine&#x0D; (bend.), carbonyl and p. amine (str.) as compared to the samples of other locations and&#x0D; it was also the only sampling location that had a silicate group. Moreover, sample&#x0D; location number 13 was the only location that had an extra functional group of isocyanide&#x0D; or alkynes HC functional group. For the dust storm samples of location numbers 16, 17&#x0D; and 18 had also all the above mentioned 9 functional groups except the alkanes HC&#x0D; functional group. On the other hand, the concentration ranges of the studied heavy metals&#x0D; were (0.20 – 3.20), (2.02 – 5.45) and (2.89 – 45.50) mg dust kg-1 dust for As, Co and V&#x0D; respectively in all the studied locations.

Beyond Creation of Mesoporosity: The Advantages of Polymer‐Based Dual‐Function Templates for Fabricating Hierarchical Zeolites

Direct synthesis of hierarchical zeolites currently relies on the use of surfactant‐based templates to produce mesoporosity by the random stacking of 2D zeolite sheets or the agglomeration of tiny zeolite grains. The benefits of using nonsurfactant polymers as dual‐function templates in the fabrication of hierarchical zeolites are demonstrated. First, the minimal intermolecular interactions of nonsurfactant polymers impose little interference on the crystallization of zeolites, favoring the formation of 3D continuous zeolite frameworks with a long‐range order. Second, the mutual interpenetration of the polymer and the zeolite networks renders disordered but highly interconnected mesopores in zeolite crystals. These two factors allow for the synthesis of single‐crystalline, mesoporous zeolites of varied compositions and framework types. A representative example, hierarchial aluminosilicate (meso‐ZSM‐5), has been carefully characterized. It has a unique branched fibrous structure, and far outperforms bulk aluminosilicate (ZSM‐5) as a catalyst in two model reactions: conversion of methanol to aromatics and catalytic cracking of canola oil. Third, extra functional groups in the polymer template can be utilized to incorporate desired functionalities into hierarchical zeolites. Last and most importantly, polymer‐based templates permit heterogeneous nucleation and growth of mesoporous zeolites on existing surfaces, forming a continuous zeolitic layer. In a proof‐of‐concept experiment, unprecedented core–shell‐structured hierarchical zeolites are synthesized by coating mesoporous zeolites on the surfaces of bulk zeolites.

Studies on the preferred uracil–adenine base pair at the cleavage site of 10–23 DNAzyme by functional group modifications on adenine

10–23 DNAzyme is capable of catalytically cleaving RNA substrates with the preferred cleavage sites rAU and rGU, in which the common base pair U-dA0 forms between the substrate and the DNAzyme in the cleavage reaction. Here its conservation was studied with base modifications on dA and extra functional groups introduced. The nitrogen atom at 7- or 8-position of adenine was demonstrated to be equally important for the cleavage reaction, although it is not related to the thermal stability of the base pair. Deletion of 6-amino group led to decreased stability of the base pair and a slight slower reaction rate. Extra functional groups through 6-amino group were not favorably accommodated in the cleavage site. From these modifications at the level of functional groups, it demonstrated that the base pair U-dA0 not only contributes to the recognition and binding stability, but also it is involved in the active catalytic center by its functional groups and base stacking. This kind of chemical modifications with 7-substituted 8-aza-7-deaza-2′-deoxyadenosine at dA0 is favorable for the introduction of signal molecules for mechanistic studies and biological applications, without significant loss of the catalytic function and structural destruction.

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction.

Functionalized oligonucleotides have recently gained increased attention for incorporation in modified nucleic acid structures both for the design of aptamers with enhanced binding properties as well as the construction of catalytic DNA and RNA. As a shortcut alternative to the incorporation of multiple modified residues, each bearing one extra functional group, we present here a straightforward method for direct linking of functionalized amino acids to the nucleoside base, thus equipping the nucleoside with two extra functionalities at once. As a proof of principle, we have introduced three amino acids with functional groups frequently used as key-intermediates in DNA- and RNAzymes via an efficient and straightforward domino carboxamidation reaction.