Nanoscale designing of metal organic framework moieties as efficient tools for environmental decontamination

Environmental pollutants, being a major and detrimental component of the ecological imbalance, need to be controlled. Serious health issues can get intensified due to contaminants present in the air, water, and soil. Accurate and rapid monitoring of environmental pollutants is imperative for the detoxification of the environment and hence living beings. Metal-organic frameworks (MOFs) are a class of porous and highly diverse adsorbent materials with tunable surface area and diverse functionality. Similarly, the conversion of MOFs into nanoscale regime leads to the formation of nanometal-organic frameworks (NMOFs) with increased selectivity, sensitivity, detection ability, and portability. The present review majorly focuses on a variety of synthetic methods including the ex situ and in situ synthesis of MOF nanocomposites and direct synthesis of NMOFs. Furthermore, a variety of applications such as nanoabsorbent, nanocatalysts, and nanosensors for different dyes, antibiotics, toxic ions, gases, pesticides, etc., are described along with illustrations. An initiative is depicted hereby using nanostructures of MOFs to decontaminate hazardous environmental toxicants.

Research progress on near-infrared long persistent phosphor materials in biomedical applications

After excitation is stopped, long persistent phosphor materials (LPPs) can emit light for a long time. The most important feature is that it allows the separation of excitation and emission in time. Therefore, it plays a vital role in various fields such as data storage, information technology, and biomedicine. Owing to the unique mechanism of storage and luminescence, LPPs can avoid the interference of sample autofluorescence, as well as show strong tissue penetration ability, good afterglow performance, and rich spectral information in the near-infrared (NIR) region, which provides a broad prospect for the application of NIR LPPs in the field of biomedicine. In recent years, the development and applications in biomedical fields have been advanced significantly, such as biological imaging, sensing detection, and surgical guidance. In this review, we focus on the synthesis methods and luminescence mechanisms of different types of NIR LPPs, as well as their applications in bioimaging, biosensing detection, and cancer treatment in the field of biomedicine. Finally, future prospects and challenges of NIR LPPs in biomedical applications are also discussed.

Synthesis and shaping of metal-organic frameworks: a review

Metal-organic frameworks (MOFs) possess excellent advantages, such as high porosity, large specific surface area, and an adjustable structure, showing good potential for applications in gas adsorption and separation, catalysis, conductivity, sensing, magnetism, etc. However, they still suffer from significant limitations in terms of the scale-up synthesis and shaping, hindering the realization of large-scale commercial applications. Despite some attempts having been devoted to addressing this, challenges remain. In this paper, we outline the advantages and drawbacks of existing synthetic routes such as electrochemistry, microwave, ultrasonic radiation, green solvent reflux, room temperature stirring, steam-assisted transformation, mechanochemistry, and fluid chemistry in terms of scale-up production. Then, the shaping methods of MOFs such as extrusion, mechanical compaction, rolling granulation, spray drying, gel technology, embedded granulation, phase inversion, 3D printing and other shaping methods for the preparation of membranes, coatings and nanoparticles are discussed. Finally, perspectives on the large-scale synthesis and shaping of MOFs are also proposed. This work helps provide in-depth insight into the scale-up production and shaping process of MOFs and boost commercial applications of MOFs.

Ultrasound Irradiation Assisted Synthesis of Luminescent Nano Amide-Functionalized Metal-Organic Frameworks; Application Toward Phenol Derivatives Sensing

Two nano amide-functionalized metal-organic frameworks (MOFs) with molecular formula [Co(oba) (bpta)]·(DMF)₂ TMU-50 and [Co₂(oba)₂ (bpfn)]·(DMF)_2.5 TMU-51 obtained under ultrasonic method without any surfactants. The only difference between the two selected amide functionalized pillar ligands, N,N′-bis(4-pyridinyl)-terephthalamide (bpta), and N,N′-bis-(4-pyridylformamide)-1,5-naphthalenediamine (bpfn), is related to the naphthyl group, which led to the different luminescence properties of the nano frameworks. In this study, the special ability of the luminescent nano MOFs were investigated to sensitize nitroaromatic compounds. Due to its unique and porous framework, Nano TMU-50 shows a good sensitivity towards nitro phenol by strong fluorescence emission with a detection limit of 2 × 10^–3 mM⁻¹. Both nano MOF structures were characterized via many analyses such as powder X-ray diffraction, Field Emission Scanning Electron Microscopy (FE-SEM), elemental analysis, and FTIR spectroscopy. Moreover, the effect of a number of important parameters including initial reagent concentrations, power of ultrasound, time on morphology, and size of nano structures were examined. According to the fluorescence titration results, the activated nano-TMU-50 detected NP selectively with a quick response.

Nanoscale covalent organic frameworks: from controlled synthesis to cancer therapy

Covalent organic frameworks (COFs), as a new type of crystalline porous materials, mainly consist of light-weight elements (H, B, C, N and O) linked by dynamic covalent bonds to form periodical structures of two or three dimensions. As an attribute of their low density, large surface area, and excellent adjustable pore size, COFs show great potential in many fields including energy storage and separation, catalysis, sensing, and biomedicine. However, compared with metal organic frameworks (MOFs), the relatively large size and irregular morphology of COFs affect their biocompatibility and bioavailability in vivo, thus impeding their further biomedical applications. This Review focuses on the controlled design strategies of nanoscale COFs (NCOFs), unique properties of NCOFs for biomedical applications, and recent progress in NCOFs for cancer therapy. In addition, current challenges for the biomedical use of NCOFs and perspectives for further improvements are presented.

Nanostructured materials via green sonochemical routes - Sustainability aspects

The production of environmentally friendly nanostructured materials with well-defined properties is a major challenge. Characteristics of the nanomaterials such as dimensionality, size and morphology strongly affect their performance in various applications. Additionally, sustainability considerations require an acceptable level of efficiency while being economically feasible and environmentally benign. The use of ultrasonic irradiation (UI) is a green and powerful technology, which can be applied for the synthesis of a variety of nanostructured materials. This review critically discusses the progress made in the fabrication of environmentally benign engineered nanomaterials with various dimensionalities (i.e., zero, one, two, or three dimensions) assisted by UI. The evolution and current status in this area are further illustrated using a scientometric approach. Application of UI for the synthesis of nanostructured materials has been also assessed according to the main sustainability pillars including the performance and environmental compatibility, as well as the relevant economic and social considerations. The outlook as well as recommendations for future research has been also provided and discussed towards the promotion of sustainable nanomaterials synthesis and application in various fields.

Templated interfacial synthesis of metal-organic framework (MOF) nano- and micro-structures with precisely controlled shapes and sizes

Metal-organic frameworks (MOF) are an emerging class of microporous materials with promising applications. MOF nanocrystals, and their assembled super-structures, can display unique properties and reactivities when compared with their bulk analogues. MOF nanostructures of 0-D, 2-D, and 3-D dimensions can be routinely obtained by controlling reaction conditions and ligand additives, while formation of 1-D MOF nanocrystals (nanowires and nanorods) and super-structures has been relatively rare. We report here a facile templated interfacial synthesis methodology for the preparation of a series of 1-D MOF nano- and micro-structures with precisely controlled shapes and sizes. Specifically, by applying track-etched polycarbonate (PCTE) membranes as the templates and at the oil/water interface, we rapidly and reproducibly synthesize zeolitic imidazolate framework-8 (ZIF-8) and ZIF-67 nano- and micro structures of sizes ranging from 10 nm to 20 μm. We also identify a size confinement effect on MOF crystal growth, which leads to single crystals under the most restricted conditions and inter-grown polycrystals at larger template pore sizes, as well as surface directing effects that influence the crystallographic preferred orientation. Our findings provide a potentially generalizable method for controlling the size, morphology, and crystal orientations of MOF nanomaterials, as well as offering fundamental understanding into MOF crystal growth mechanisms.

A hybrid nano-MOF/polymer material for trace analysis of fluoroquinolones in complex matrices at microscale by on-line solid-phase extraction capillary electrophoresis

A hybrid material (nano-metal organic framework@organic polymer, named as nano-MOF@polymer) was applied for the first time as sorbent for on-line solid-phase extraction capillary electrophoresis with ultraviolet detection (SPE-CE-UV). The resulting material was prepared building layer-by-layer a HKUST-1 (Hong Kong University of Science and Technology-1) nano-MOF onto the polymer surface, which allowed controlling the thickness and maximizing the active surface area. The sorbent was widely characterized at micro- and nano-scale to validate the synthesis and to establish the material properties. Then, fritless microcartridges (2 mm) were assembled by packing only a few micrograms of sorbent particles and investigated for preconcentration of fluoroquinolones (FQs) in several real samples (river water, human urine and whole cow milk). Under the optimized conditions, the sample (ca. 60 μL) was loaded in separation background electrolyte (BGE, 50 mM phosphate (pH 7)), and retained analytes were eluted using a small volume of 2% v/v formic acid in methanol (ca. 50 nL). The SPE-CE-UV method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), repeatability, reproducibility and reusability. The developed method showed a LOD decreasing until 1 ng L^-1 when larger volumes of sample were loaded (ca. 180 μL), which was 500,000 times lower than by CE-UV. This undescribed sensitivity enhancement would arise from the homogenous and populated MOF nano-domains and the appropriate permeability of the hybrid material, which would promote high extraction efficiency and loading capacity. Furthermore, the sorbent showed appropriate selectivity regardless the analyzed complex environmental, biological or food matrix samples, achieving excellent detectability and recoveries (>90%).

Recent advances in process engineering and upcoming applications of metal-organic frameworks

Progress in metal-organic frameworks (MOFs) has advanced from fundamental chemistry to engineering processes and applications, resulting in new industrial opportunities. The unique features of MOFs, such as their permanent porosity, high surface area, and structural flexibility, continue to draw industrial interest outside the traditional MOF field, both to solve existing challenges and to create new businesses. In this context, diverse research has been directed toward commercializing MOFs, but such studies have been performed according to a variety of individual goals. Therefore, there have been limited opportunities to share the challenges, goals, and findings with most of the MOF field. In this review, we examine the issues and demands for MOF commercialization and investigate recent advances in MOF process engineering and applications. Specifically, we discuss the criteria for MOF commercialization from the views of stability, producibility, regulations, and production cost. This review covers progress in the mass production and formation of MOFs along with future applications that are not currently well known but have high potential for new areas of MOF commercialization.

Anthracene removal from water samples using a composite based on metal-organic-frameworks (MIL-101) and magnetic nanoparticles (Fe3O4)

Polycyclic hydrocarbons constitute an important source of very dangerous pollutants. Different materials have been used as adsorbent for their removal, but they present difficulties in the separation process. The use of a material based on metal-organic framework (MOF) with large pores and high surface area and magnetic nanoparticles with superparamagnetic properties is an interesting strategy. In this work a magnetic composite based on MOF (MIL-101) and Fe₃O₄ magnetic nanoparticles (Fe₃O₄/MIL-101) was obtained by a simple synthesis method and used as adsorbent for the removal of anthracene. The composite was characterized by transmission electron microscopy, x-ray powder diffraction and vibrating sample magnetometer. The results showed that kinetic data followed a first-order model and equilibrium data were well fitted by the Langmuir model. The maximum adsorption capacity was 12.7 mg g^-1 at pH 6 in 60 min of exposure. The composite was applied for the adsorption of anthracene in water samples reaching more than 95% of anthracene removal in 1 h of contact. The composite material was effectively separated using an external magnet, and no further centrifugation or filtration processes were needed. This composite is a great alternative to remove polycyclic hydrocarbons from water samples and has potential to extend to the removal of other contaminants.

Ultrasonic-assisted synthesis of the nanostructures of a Co(II) metal organic framework as a highly sensitive fluorescence probe of phenol derivatives

Nanostructures of a metal-organic framework with chemical formula, [Co(BDC)(L*)]_n.DMF (TMU-40), BDC = 1,4-benzendicarboxylate, L* = 5,6-dipyridin-4-yl-1,2,3,4-tetrahydropyrazine, under ultrasonic irradiation at ambient temperature and atmospheric pressure were prepared and characterized by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Sonication time, concentration of initial reagents and ultrasonic generator power effects on the size and morphology of nano-structured compounds were studied. TMU-40 (for Tarbiat Modares University) displayed a good potential as a luminescent sensor against phenol derivatives consist of phenol, 4-aminophenol, 4-methylphenol and 4-chlorophenol. Nano-sized TMU-40 showed the better sensing performance in comparison to its bulk phase. The nano TMU-40 displayed very selective and sensitive in detection of phenol derivatives. The detection limit amounts of 15 nM and 63 nM were achieved for 4-aminophenol in nano TMU-40 and bulk TMU-40, respectively. The special structure and fluorescent character of L* ligand and high surface area of nano MOF provide an effective interaction between MOF and phenolic analytes to selectively and sensitively detect of the analyte molecules.

High Frequency Sonoprocessing: A New Field of Cavitation-Free Acoustic Materials Synthesis, Processing, and Manipulation

Ultrasound constitutes a powerful means for materials processing. Similarly, a new field has emerged demonstrating the possibility for harnessing sound energy sources at considerably higher frequencies (10 MHz to 1 GHz) compared to conventional ultrasound (⩽3 MHz) for synthesizing and manipulating a variety of bulk, nanoscale, and biological materials. At these frequencies and the typical acoustic intensities employed, cavitation-which underpins most sonochemical or, more broadly, ultrasound-mediated processes-is largely absent, suggesting that altogether fundamentally different mechanisms are at play. Examples include the crystallization of novel morphologies or highly oriented structures; exfoliation of 2D quantum dots and nanosheets; polymer nanoparticle synthesis and encapsulation; and the possibility for manipulating the bandgap of 2D semiconducting materials or the lipid structure that makes up the cell membrane, the latter resulting in the ability to enhance intracellular molecular uptake. These fascinating examples reveal how the highly nonlinear electromechanical coupling associated with such high-frequency surface vibration gives rise to a variety of static and dynamic charge generation and transfer effects, in addition to molecular ordering, polarization, and assembly-remarkably, given the vast dimensional separation between the acoustic wavelength and characteristic molecular length scales, or between the MHz-order excitation frequencies and typical THz-order molecular vibration frequencies.

Metal-Organic Frameworks for Food Safety

Food safety is a prevalent concern around the world. As such, detection, removal, and control of risks and hazardous substances present from harvest to consumption will always be necessary. Metal-organic frameworks (MOFs), a class of functional materials, possess unique physical and chemical properties, demonstrating promise in food safety applications. In this review, the synthesis and porosity of MOFs are first introduced by some representative examples that pertain to the field of food safety. Following that, the application of MOFs and MOF-based materials in food safety monitoring, food processing, covering preservation, sanitation, and packaging is overviewed. Future perspectives, as well as potential opportunities and challenges faced by MOFs in this field will also be discussed. This review aims to promote the development and progress of MOF chemistry and application research in the field of food safety, potentially leading to novel solutions.

Metal Organic Frameworks (MOFs) and ultrasound: A review

Metal-organic frameworks (MOFs) have received a lot of attention due to their unique properties and abundant functionalities. Permanent porosity and high surface area are just a few traits that have made them attractive to researchers. They can be prepared as task-specific materials by exploiting the functional group variety and tuning their size and geometry. The main purpose of this review is to present an alternative method of preparing MOF crystals and underline the advantages of ultrasound assisted (sonochemical) synthesis. State of the art ultrasound assisted techniques for the preparation of MOFs in nanoscale are presented. Optimization of morphology and particle size is highlighted throughout this work, as we discuss the effects of various factors, such as energy input, reagent concentration, adequate solvents, reaction time and more.

High-sensitivity detection of nitroaromatic compounds (NACs) by the pillared-layer metal-organic framework synthesized via ultrasonic method

Nanorods of zinc(II) based metal-organic framework (MOF) were prepared via ultrasonic method without any surfactants at room temperature and atmospheric pressure. Control of particle size and morphology was enhanced in this synthesis method. Nanorods of pillared-layer metal organic framework, [Zn₂(ubl)₂(bipy)]·DMF (TMU-18), where ubl (urea-based ligand) is 4,4'-carbonylbis(azanediyl)dibenzoic acid, 4,4'-Bipyridine (bipy) DMF = N,N-dimethyl formamide), was synthesized under ultrasound irradiation in different concentrations of initial precursor. The nano structure and morphology of the synthesized MOF were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction, elemental analysis and FT-IR spectroscopy. Moreover, Fluorescence emissions of nanorods have been studied. Luminescent MOFs (LMOFs) have shown great potential as sensor for various nitro explosives by modulating the luminescence behavior in presence of nitro explosives. Urea-functionalized MOF shows high selectivity for sensing of the nitro explosive 2,4,6-trinitrophenol (TNP) even in the presence of other nitroaromatic compounds in methanol solution. Fluorescence intensity decreased with increasing contents of nitroaromatics in organic solution due to fluorescence quenching effect. The ultrasound method has some advantages such as short duration time of reaction, no need to high temperatures and pressures for synthesis nano-materials and low costs in comparison to other methods. Considering these advantages we used ultrasonic method to produce these nanorods which show high sensitivity in detecting nitroaromatics.

Ultrasonic polymerization of CuO@PNIPAM and its temperature tuning glucose sensing behavior

The extraordinary high pressure and temperature produced during cavitation is crucial for ultrasonic sonochemistry. However, the cavitation effect is usually confined to a small zone nearby the ultrasonic horn, outside of which ultrasound produces much less effects on chemical reaction. In present work, in order to expand the range of effective zone and intensify the cavitation effect, N₂ aeration was introduced to an ultrasonic polymerization process of CuO@PNIPAM in aqueous solution. By increasing the number of bubble nucleus gathered on the CuO surface and lowering the surface tension of the aqueous solution, the cavitation effect is intensified on the CuO surface within the whole reaction vessel, which benefits the covalently bonding between PNIPAM and CuO to a large degree and results in the formation of CuO@PNIPAM hybrid composite with excellent interfacial bonding. It is promising that the hybrid composite can be applied as temperature responsive glucose sensing platform with ON and OFF states due to the wettability change of PNIPAM versus temperature.

2-Hydroxy-N'-((Thiophene-2-yl)methylene)benzohydrazide: Ultrasound-Assisted Synthesis and Corrosion Inhibition Study

2-Hydroxy-N'-((thiophene-2-yl)methylene)benzohydrazide (HTMBH) was synthesized by conventional method as well as by ultrasonication (US). The ultrasound-assisted synthesis of HTMBH was found to have good yield and be more eco-friendly compared to the conventional method of synthesis. The synthesized compound HTMBH was characterized by Fourier transform infrared, 1H NMR, and CHN analyses. The corrosion inhibition behavior of HTMBH was investigated using gravimetric and electrochemical methods in 0.5 M H2SO4. The thermodynamic adsorption parameters revealed that HTMBH was adsorbed on the mild steel surface in both ways, physically and chemically, although physisorption is predominant. The study of activation parameters revealed that it is the increase in activation energy that is a prominent factor to lower the corrosion rate in acid medium. Atomic force microscopy analysis is also carried out to investigate the effect of HTMBH on the surface of mild steel surface in acid solution. The contact angle measurement showed decreased affinity of mild steel surface for acid solution containing HTMBH. The results obtained from all of these methods showed good consistency.

Ultrasound irradiation effect on morphological properties of a 3D nano zinc(II) supramolecular coordination polymer

Nano-structures of [Zn(L)(atpt)]_n (1) (L=1,2-bis(2-methylbenzimidazol-1-ylmethyl)benzene and H₂atpt=2-aminoterephthalic acid) were obtained by hydrothermal and sonochemical approaches, characterized by scanning electron microscopy (SEM), IR, powder X-ray diffraction (PXRD), and elemental analysis. CP 1 features a 2D (4,4) network with the point symbol {4⁴.6²}, the 3D supramolecular architecture in CP 1 is controlled through π⋯π stacking interactions. The influence of various concentrations of initial reagents, power of ultrasound irradiation, and ultrasound time on the morphology and size of nano-structured CP 1 were studied in detail. In addition, the luminescence and photocatalytic properties of the nanoparticles of CP 1 for the degradation of methyl blue (MB) have also been investigated.

Ultrasonic green synthesis of an Ag/CP nanocomposite for enhanced photodegradation effectiveness

A nanoparticle of cobalt(II) coordination polymer (CP), [Co(L)(npht)]_n (1) (H₂npht=4-nitrophthalic acid, L=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene) and its nanocomposite (Ag/CP 1) were obtained by the sonochemical approach and characterized by IR, elemental analysis, thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRPD). CP 1 shows a 1D double chain containing two different helical chains, which is further extended into a two-dimensional supramolecular framework by C-H⋯O hydrogen bonding interactions. The photoluminescence properties and photocatalytic properties of the nanoparticles of CP 1 and Ag/CP 1 on the degradation of methylene blue (MB) were investigated, Ag/CP 1 exhibited excellent photocatalytic activity under UV and visible light, which can be attributed to the strong interactions between Ag nanorods and CP 1, which lead to electron-hole pair separation between Ag nanorods and CP 1. In addition, the photocatalytic mechanism is also carried out by introducing t-butyl alcohol (TBA) as a widely used ·OH scavenger. The influence of ultrasound irradiation time and power on the morphology and size of the nanostructure CP 1 were studied. The results indicated that a decrease in time and an increase in power led to a decrease of particle size.

Influence of the ultrasound-assisted synthesis of Cu-BTC metal-organic frameworks nanoparticles on uptake and release properties of rifampicin

In this work, we study uptake and release properties of rifampicin (denoted henceforth as Rif) from ultrasound-assisted synthesis Cu-BTC nanoparticles in comparison with bulk Cu-BTC and activated carbon. To explore the absorption ability of the Cu-BTC to Rif, fresh sample of Cu-BTC was immersed in an aqueous solution of Rif and were monitored in real time with UV/vis spectroscopy. Results show that the adsorbed quantity of Rif over nano Cu-BTC (denoted henceforth as I) is much higher than those over a bulk Cu-BTC (denoted henceforth as II) and activated carbon. In compound I and all of the nano-MOFs the channel length is decreased so that the amount of adsorption is increased a little. The samples were characterized with X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and UV/vis spectroscopy.

Ultrasonic assisted synthesis of a tetrazine functionalized MOF and its application in colorimetric detection of phenylhydrazine

TMU-34(-2H), [Zn(OBA)(DPT)_0.5].DMF, has been sonochemically synthesized by applying H₂OBA, (4,4'-oxybis(benzoic acid)), as the dicarboxylate linker, and DPT, (3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine), as pillar spacer. Sonication time, concentration of initial reagents, sonication power and molar ratio of pyridine as modulator has been optimized to synthesize nano powder of TMU-34(-2H) including uniform plate morphology. Nano TMU-34(-2H), can detect phenylhydrazine (PH) by color changing from pink to deep purple. As a comparison, nano and crystal samples of TMU-34(-2H) were treated to detect PH. Experiments show that nano TMU-34(-2H) has better detection limit and response time.

Sonochemical synthesis of two new zinc(II) 1,10-phenanthroline coordination supramolecular compounds: New precursors to produce nano-sized zinc(II) oxide

Nanoparticles of two zinc(II) coordination supramolecule compounds (CSCs), [Zn(L)Cl2] (1) and [Zn(L)Br2] (2) L=1,10-phen=1,10-phenanthroline ligand, have been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compounds 1 and 2 imply that the Zn⁺² ions are four coordinated. Topological analysis shows that the compound 1 and 2 are new topology for net: 1,3M4-1. Nanoparticles of zinc(II) oxide have been prepared by calcination of two different zinc(II) CPs at 500°C that were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and IR spectroscopy.

Nanostructured metal–organic frameworks, TMU-4, TMU-5, and TMU-6, as novel adsorbents for solid phase microextraction of polycyclic aromatic hydrocarbons

Zn(ii) based metal–organic frameworks were coated onto stainless steel wire and applied to the headspace solid phase microextraction of PAHs.

Enhancement of photocatalytic performance in two zinc-based metal–organic frameworks by solvent assisted linker exchange

Solvent-assisted linker exchange (SALE) was performed on two pillared metal–organic frameworks (MOFs), [Zn₂(oba)₂(4-bpdb)]_n·(DMF)₂ (TMU-4) and [Zn(oba)(4-bpmb)_0.5]_n·(DMF)_1.5 (TMU-6), to tune their photocatalytic properties.

Sonochemical procedures; the main synthetic method for synthesis of coinage metal ion supramolecular polymer nano structures

During the last two decades, supramolecular polymers have received great attention and the number of their synthesized compounds is still growing. Although people have long been interested in their crystalline network form it was only until 2005 that the first examples of nano- or microscale coordination polymers particles be demonstrated. This review tries to give an overview of all nano supramolecular compounds which were reported from coinage metal ions, their attributed synthetic procedures and to investigate the relation between the dimensions of coinage metal ions (Cu, Ag and Au) coordination and supramolecular polymers with their nano-structural morphologies and dimensions. Eleven compounds (from twenty compounds) with nano-structure morphology were prepared by sonochemical process and Ag(I) coordination and supramolecular polymer nano-structures can be easily prepared by sonochemical procedures.

Shadow-casted ultrathin surface coatings of titanium and titanium/silicon oxide sol particles via ultrasound-assisted deposition

Ultrasound-assisted deposition (USAD) of sol nanoparticles enables the formation of uniform and inherently stable thin films. However, the technique still suffers in coating hard substrates and the use of fast-reacting sol-gel precursors still remains challenging. Here, we report on the deposition of ultrathin titanium and titanium/silicon hybrid oxide coatings using hydroxylated silicon wafers as a model hard substrate. We use acetic acid as the catalyst which also suppresses the reactivity of titanium tetraisopropoxide while increasing the reactivity of tetraethyl orthosilicate through chemical modifications. Taking the advantage of this peculiar behavior, we successfully prepared titanium and titanium/silicon hybrid oxide coatings by USAD. Varying the amount of acetic acid in the reaction media, we managed to modulate thickness and surface roughness of the coatings in nanoscale. Field-emission scanning electron microscopy and atomic force microscopy studies showed the formation of conformal coatings having nanoroughness. Quantitative chemical state maps obtained by x-ray photoelectron spectroscopy (XPS) suggested the formation of ultrathin (<10nm) coatings and thickness measurements by rotating analyzer ellipsometry supported this observation. For the first time, XPS chemical maps revealed the transport effect of ultrasonic waves since coatings were directly cast on rectangular substrates as circular shadows of the horn with clear thickness gradient from the center to the edges. In addition to the progress made in coating hard substrates, employing fast-reacting precursors and achieving hybrid coatings; this report provides the first visual evidence on previously suggested "acceleration and smashing" mechanism as the main driving force of USAD.

Synthesis of porous Cu-BTC with ultrasonic treatment: Effects of ultrasonic power and solvent condition

Cu-BTC (BTC=1,3,5-benzenetricarboxylate) metal organic framework (MOF) was synthesized using different solvent conditions with ultrasonic treatment. Solvent mixtures of water/N,N-dimethylformamide (DMF), water/ethanol were used for the reactions with or without a variety of bases under 20 kHz ultrasonically treated conditions. Prepared crystals were purified through 30 min of sonication to remove unreacted chemicals. Treatment time and ultrasonic power effects were compared to get optimum synthetic condition. The characterization of MOF powders was performed by scanning electron microscopy, X-ray powder diffraction, infrared-spectroscopy, thermo-gravimetric analysis and specific surface determination using the BET method. Isolated crystal yields varied with different solvent and applied ultrasonic power conditions. A high isolated crystal yield of 86% was obtained from water/ethanol/DMF solvent system after 120 min of ultrasonic treatment at 40% power of 750 W. Different solvent conditions led to the formation of Cu-BTC with different surface area, and an extremely high surface area of 1430 m(2)/g was obtained from the crystals taken with the solvent condition of water:DMF=70:30.

Facile room temperature synthesis of metal–organic frameworks from newly synthesized copper/zinc hydroxide and their application in adsorptive desulfurization

Facile synthesis of metal–organic frameworks was demonstrated via directly adding organic ligands solution into the newly synthesized copper/zinc hydroxide solution.

Sonochemical synthesis of nanoplates of two Cd(II) based metal-organic frameworks and their applications as precursors for preparation of nano-materials

Nano plates of two Cd(II)-based metal-organic frameworks, [Cd2(oba)2(4-bpdb)2]n ·(DMF)x(TMU-8) and [Cd(oba)(4,4'-bipy)]n ·(DMF)y (TMU-9) were synthesized via sonochemical reaction by using various time and concentrations of initial reagents and power of irradiation and characterized by scanning electron microscopy, X-ray powder diffraction and IR spectroscopy. Moreover, the effect of triethylamine on speed of nucleation during the synthesis was investigated. Thermolysis of these MOFs at 550°C under air atmosphere yields CdO nanoparticles.

Sonochemical synthesis of a new nano-sized cerium(III) coordination polymer and its conversion to nanoceria

Nanoparticles of a new two-dimensional cerium(III) coordination polymer compound, [Ce(pzdc)(pzdcH)(H2O)3]n (1), (H2pzdc=2,3-pyrazinedicarboxylic acid), have been synthesized by a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses. Compound 1 was structurally characterized by single crystal X-ray diffraction and was shown that it consists of 2D sheets that construct a three-dimensional supramolecular architecture via non-covalent interactions i.e. hydrogen bonding. The thermal stability of compound 1 both for its crystals and nanostructures has been studied by the thermal gravimetric (TG) method and compared with each other. The role of ultrasound irradiation power and the concentration of initial reactants on the size and morphology of the nano-structured compound 1, has been investigated. Calcination of compound 1 at 800°C under air atmosphere yields ceria nanoparticles. Furthermore, the fluorescent properties of compound 1 at room temperature were studied.

Facile synthesis of gallium oxide hydroxide by ultrasonic irradiation of molten gallium in water

This work describes the single-step synthesis of GaO(OH) by ultrasonic irradiation of molten gallium in warm water. The ultrasonic energy causes dispersion of the liquid gallium into micrometric spheres, as-well-as decomposition of some of the water into H and OH radicals. The OH radicals and the dissolved oxygen react on the surface of the gallium spheres to form crystallites of GaO(OH). These crystallites prevent the re-coalescence of the gallium spheres, and as the reaction proceeds all the gallium is converted into crystalline GaO(OH).