Inorganic Hybrid Materials Research Articles

A durable MOF-303-coated stainless steel mesh with robust anti-oil-fouling performance for multifunctional oil/water separation

Durable anti-fouling membranes for the effective and simultaneous removal of insoluble oil droplets and organic dyes from wastewater need to be developed urgently. Metal–organic frameworks (MOFs) are emergent porous organic–inorganic hybrid materials, that have been attracting increasing attention because of wide applications, such as liquid separation, dye adsorption, and catalysis. However, the preparation of a well-intergrown MOF membrane remains challenging, because of poor water stability and low affinity between MOF grains and substrates. Herein, we report the first preparation of a continuous, water-stable MOF-coated mesh with an ordered porous structure by using a simple hydrothermal method to realize array growth of MOF-303 crystals on a layered double-hydroxide modified mesh surface. As the MOF-303 has a high water uptake capability, the prepared MOF-303 @SSM with sufficient surface hydration exhibited superhydrophilicity-underwater superoleophobicity and excellent antifouling performance. This membrane was used for gravity-driven separation of oil/water mixtures at high flux (> 12308 L m−2 h−1) and efficiency (> 99.35%). This membrane simultaneously and efficiently removed an oil-in-water (O/W) emulsion and water-soluble dyes, and exhibited outstanding reusability. More importantly, MOF-303 @SSM is promising for practical applications because of outstanding physical and chemical stability, as well as high thermal stability, under harsh environmental conditions. Therefore, this study provides a promising strategy to develop a functional MOF membrane for purifying hazardous wastewater.

Effect of Doping on the Bandgap of the Organic–Inorganic Hybrid Ferroelectric Material [C6N2H18]Bi1−xSbxI5 (0.0 < x < 1.0)

The rapidly developing organic–inorganic hybrid chalcogenide solar cells have now become a hot topic of interest. However, the bandgap of inorganic ferroelectric materials with a typical chalcogenide structure is too wide to match the solar spectrum, while the ferroelectricity of organic-inorganic hybrid chalcogenide materials with a narrow bandgap, meth amide–lead–iodine, is not obvious, and the lead element causes environmental pollution. The recently discovered organic–inorganic hybrid material [C6N2H18]BiI5 with good ferroelectricity and the narrowest bandgap of molecular ferroelectrics can absorb visible light in the range of 380 nm to 660 nm, and compound [C6N2H18]SbI5 with the Bi cognate element Sb was also synthesized. In this paper, we designed the first experiment to prepare thin films by mixing and doping the above two materials in five different molar ratios, and we comparatively studied the changes in crystal structure, surface morphology, and photophysical properties of the prepared multicomponent hybrid films according to the mixing ratio. A theoretical model was developed to calculate and analyze the bandgap of the hybrid doped compounds and compare it with the experimental values. It was found that the absorption spectra of the multicomponent hybrid films were red-shifted relative to the original material, indicating that the forbidden bandwidth was reduced to absorb a wider range of visible light, and the reason for this was thought to be the narrowing of the bandgap due to doping. When the mixing ratio was 0.4:0.6, the bandgap was the narrowest and the light absorption was the best; the highest quality of the film was obtained when the mixing ratio was 0.5:0.5.

The Influence of Boron on the Structure and Properties of Hybrid Compounds Containing Zirconium and Phosphorus.

In the present work, novel organic–inorganic hybrid materials containing boron, zirconium, and phosphorus were synthesized at different molar ratios, using the sol–gel method, starting from zirconyl chloride hexa-hydrate, triethyl borate, and phenyl phosphonic acid as the precursors. The sol–gel process is used for the first time in the present work in order to obtain organic–inorganic hybrids (or the so-called inorganic polymers) containing together boron, zirconium, and phosphorus. The sol–gel syntheses were performed at room temperature in ethanol. Zirconium containing compounds are already well known for their applications in medicine in restorative or prosthetic devices, including dental implants, knee and hip replacements, middle-ear ossicular chain reconstruction, and so on. Zirconium is a strong transition metal, which started to replace hafnium and titanium in the last decade in important applications. On the other hand, boron has the capability (similar to carbon) to form stable covalently bonded molecular networks. In addition to this capability, boron also offers mixed metallic and nonmetallic properties, because of its place on the periodic table, at the border between metals and nonmetals. Boron is responsible for the higher thermal stability of synthesized hybrid compounds. In the structure of those hybrid compounds, zirconium, boron, and phosphorus atoms are always connected via an oxygen atom, by P-O-Zr, Zr-O-Zr, or Zr-O-B bridges.

Exploring the Vapor Phase Infiltration of Trimethylaluminum into Polyacrylonitrile Fabrics

Vapor phase infiltration (VPI) creates a hybrid organic-inorganic material by modifying the bulk of a polymer substrate with a metalorganic vapor phase precursor. In VPI, the metalorganic precursor sorbs to the polymer, then diffuses through the bulk and becomes entrapped—either by a chemical bond between the polymer and the inorganic or by a co-reaction with a second species—yielding a hybrid composed of the polymer and, often, a metal oxide. Some of the polymers that have been studied under VPI include poly(methyl methacrylate) (PMMA), polyethylene terephthalate (PET), polydimethyl siloxane (PDMS), and poly(3-hexylthiophene) (P3HT). There is a notable exception in this list: polyacrylonitrile (PAN). The high reactivity of the nitrile functional group on the backbone of the PAN polymer chain suggests PAN would perform well in VPI. PAN is used in textiles and filtration, but one of its most common applications is as a precursor to carbon fiber. Previous hybrid materials created via VPI have demonstrated new optical and thermal properties that differ from the neat polymer. If infiltrated successfully, these properties in PAN could be of use in its application spaces. In this work, we expand the VPI material space with the first study of infiltration of PAN. To explore the bounds of this system in terms of achievable inorganic loadings and hybrid material chemical structure, PAN is infiltrated with the metalorganic precursor trimethylaluminum (TMA) and co-reacted with water vapor under variable precursor exposure times, precursor desorption times, and processing temperatures. PAN is found to infiltrate with high quantities of inorganic loading (as measured by thermogravimetric analysis) that can be tuned from 1% to 17% inorganic by weight. Inorganic loading depends strongly on precursor exposure time with a sample processed at 140℃ showing a 25% increase when the exposure time is increased from 5 hours to 25 hours. Infiltration temperature also plays a significant role with hybrid materials demonstrating a 78% increase in inorganic loading when the PAN processing temperature is increased from 80℃ to 140℃. The apparent increase in inorganic loading with temperature may be related to the mass transport and reaction kinetics of the system under VPI conditions. Precursor desorption time, on the other hand, has minimal impact on inorganic loading suggesting most sorbed precursor participates in a chemical interaction with the polymer during infiltration. In exploring the resulting AlOx/PAN hybrid chemical structure with FTIR, this mechanism was supported by an observed decrease of the PAN nitrile peak at ~2240 cm-1 that scaled with inorganic loading. These structural changes in inorganic loading and chemical state are found to directly correspond to the optical (UV-Vis) and thermal (TGA) properties of the hybrid materials. The results of these characterization techniques imply that the VPI process causes a significant chemical change to the PAN fabric and suggests the process could possibly induce PAN cyclization, which may be advantageous for carbon fiber applications. Overall, this work establishes the significant and tunable inorganic loading of AlOx/PAN hybrid fabrics and expands VPI to a new polymer system.

Behavior of Iron Tetraphenylsulfonato Porphyrin Intercalated into LDH and LSH as Materials for Electrocatalytic Applications

Organic–inorganic hybrid materials were prepared by intercalation of iron 5,10,15,20 tetrakis(4-sulfonatophenyl)porphyrin complex into layered double hydroxides (ZnCr-FeTSPP LDH) and layered simple hydroxides (Zn-FeTSPP LSH) by coprecipitation. They have been characterized by ancillary techniques to compare their structural characteristics, their morphology and their ability to form films on conductive substrates in view of preparing modified electrodes for CO2 electroreduction reaction (CO2ERR). The electrochemical behavior of intercalated FeTSPP was studied by cyclic voltammetry (CV) showing the role of the nature and pH of aqueous electrolyte solutions on the FeIII/II signal. Evaluation of the CO2ERR of ZnCr-FeTSPP modified electrode was investigated by CV and preparative scale CO2 electrolysis in 0.1 M Na2SO4 aqueous solution. Whereas FeTSPP in the same electrolyte solution exhibits 18% of CO2 conversion to CO, once intercalated into ZnCr-LDH, there is no CO formation, only H2 (FY = 75%). Using the ZnCr-NO3 modified electrode, without porphyrin, the same FY of H2 was obtained. The study illustrates the problematic and the complexity of an attractive approach for the development of innovative hybrid catalysts for heterogeneous CO2ERR.Graphical abstract

Structural Optimization and Property Tunability by Halogen Regulation in Zero-Dimensional Zinc Halide Organic–Inorganic Hybrid Materials

Structural Optimization and Property Tunability by Halogen Regulation in Zero-Dimensional Zinc Halide Organic–Inorganic Hybrid Materials

Enhanced DNA nuclease activity of Momordica charantia lectin by biomimetic mineralization as hybrid copper phosphate nanoflowers and as zeolitic imidazole frameworks

Biomimetic mineralization of enzymes for enhanced stability and activity is an important area of research due to its potential applications. Inorganic materials with enzymes coated and or embedded in them, viz., protein-inorganic hybrid nanomaterials with distinctive morphology and surface characteristics are promising candidates for exploring their elevated enzymatic activity. In this work, we have developed two different types of protein inorganic nanohybrid materials using a 120 kDa lectin purified from bitter gourd seeds (Momordica charantia lectin, MCL), and (i) copper phosphate nanoflowers to result in a protein – inorganic nano hybrid material CuPNF_MCL and (ii) encapsulating the protein in zeolitic imidazole framework, ZIF8_MCL. While CuPNF_MCL showed floral morphology, the ZIF8_MCL mostly showed hexapod morphology as noticed from the microscopy data. Both the nanomaterials showed a distinctive trend of decrease in size with increase in the protein concentration used during the preparation. The nanoflowers also showed an increase in the tightness of the packing of petals with increase in the protein concentration. Powder X-Ray diffraction studies confirmed the crystallinity of the inorganic frameworks. The Fourier Transform infrared spectroscopy studies coupled with confocal imaging of the fluorophore tagged MCL embedded hybrids confirmed the presence of the protein. The MCL protein was examined for its ability to cleave DNA, i.e., nuclease activity using pBR322, wherein the form I plasmid is completely transformed into the form II / III at 2 mg/mL concentration of the protein. However, both the hybrids showed a superior nuclease activity as compared to the protein, wherein the CuPNF_MCL showed a threefold greater nuclease activity as compared to the ZIF8_MCL. The greater nuclease activity of CuPNF_MCL is attributable to its mesoporous nature with higher pore size and pore volume as compared to that in case of ZIF8_MCL, which is microporous in nature. Thus, in this paper, we have purified a nuclease like lectin from bitter gourd seeds and improved its nuclease property by converting it into inorganic hybrid nanomaterial of two types wherein higher activity was observed in the material having better porosity and surface area characteristics.

Sequential Infiltration Synthesis of Al2O3 in Biodegradable Polybutylene Succinate: Characterization of the Infiltration Mechanism.

The introduction of inorganic materials into biopolymers has been envisioned as a viable option to modify the optical and structural properties of these polymers and promote their exploitation in different application fields. In this work, the growth of Al2O3 in freestanding ∼30-μm-thick poly(butylene succinate) (PBS) films by sequential infiltration (SIS) at 70 °C via trimethylaluminum (TMA) and H2O precursors was investigated for the first time. The incorporation of Al2O3 into the PBS matrix was clearly demonstrated by XPS analysis and SEM-EDX cross-sectional images showing a homogeneous Al2O3 distribution inside the PBS films. Raman measurements on infiltrated freestanding PBS show a reduction of the signal related to the ester carbonyl group as compared to pristine freestanding PBS films. Accordingly, FTIR and NMR characterization highlighted that the ester group is involved in polymer–precursor interaction, leading to the formation of an aliphatic group and the concomitant rupture of the main polymeric chain. Al2O3 mass uptake as a function of the number of SIS cycles was studied by infiltration in thin PBS films spin-coated on Si substrates ranging from 30 to 70 nm. Mass uptake in the PBS films was found to be much higher than in standard poly(methyl methacrylate) (PMMA) films, under the same process conditions. Considering that the density of reactive sites in the two polymers is roughly the same, the observed difference in Al2O3 mass uptake is explained based on the different free volume of these polymers and the specific reaction mechanism proposed for PBS. These results assessed the possibility to use SIS as a tool for the growth of metal oxides into biopolymers, paving the way to the synthesis of organic–inorganic hybrid materials with tailored characteristics.

2,1,3-Benzothiadiazole-based bis-silylated compounds: Synthesis and use in the preparation of highly fluorescent low-contend organic–inorganic hybrid materials

Herein, we report the synthesis of bis-silylated 2,1,3-benzothiadiazole derivatives and their use in the preparation of photoactive organic–inorganic hybrid materials with extremely low fluorophore/tetraethylorthosilicate molar ratios. The organic compounds were synthesized in good to excellent yields (55 %-94 %) using Pd-catalyzed Sonogashira cross-coupling as the key step. The bis-silylated benzothiadiazoles exhibited absorption in the UV-A region (∼376 nm), attributed to fully spin- and symmetry-allowed π-π* electronic transitions. An emission located in the blue-cyan region with a high quantum yield and large Stokes shift was observed, most likely due to a charge-transfer mechanism in the excited state. BTD-containing hybrid materials were obtained through a sol–gel process, for which the dye loading and aging time were studied. Optimal reproducibility of the photophysical results was achieved when the sol–gel reaction was conducted for 10 d at 60 °C. In the solid state, the obtained hybrid materials exhibited fluorescence emission in the blue-cyan-green regions, with relatively high quantum yields (∼ 30 %). The protocol allows for the preparation of analogous photoactive hybrid materials containing very low amounts of BTD, behaving as fluorescent fumed silica.

Grafting Going Green: Toward a Sustainable Preparation of Organic-Inorganic Hybrid Materials.

Organic–inorganic hybrid materials find many applications in catalysis, nanotechnology, electronics, and many others. Grafting organic functionalities on inorganic supports is one of the most used methods for their preparation. Toluene is the solvent of choice for the grafting reaction, but it is fossil fuel-derived and not devoid of toxic effects. In this work, we explore the use of sustainable alternatives, i.e., (+)-α-pinene, (−)-β-pinene, dimethyl carbonate (DMC), (+)-limonene, and 2-methyl-tetrahydrofuran (MeTHF), as solvents for grafting. The grafting reaction between 3-aminopropyltriethoxysilane (APTS) and mesoporous ordered silica (MCM-41) was selected as a model for this study. A comparison of the rate of the grafting reaction in different solvents is reported. The resulting hybrid materials were analyzed by Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) and compared to the reference material prepared in toluene. MeTHF proved to be the best sustainable alternative to toluene for model grafting, providing a comparable product in a significantly shorter reaction time.

Reversible Phase Transition and Second-Harmonic Response Based on a Zero-Dimensional Organic–Inorganic Hybrid Compound

The organic–inorganic hybrid materials (OIHMs) with stimuli-responsive features show the important scientific attraction in a multifunctional material application field, such as optoelectronic memory and sensors. Especially, designing a functional material with both dielectric switching and second-harmonic generation (SHG) remains attractive. Herein, we report a new OIHM [C7H15NCl] SbCl4 as a phase matching nonlinear optical material and dielectric switch functional materials. It undergoes a reversible phase transition at 297 K and exhibit a harmonic generation (SHG) effect of about 0.53 times that of KH2PO4 (KDP). Meanwhile, it also possesses potential semiconducting properties. This work might provide a strategy for designing novel multifunctional materials in the field of crystals and dielectrics.

Adsorption of bisphenol A by TiO2-based organic–inorganic hybrid materials

In this study, TiO2-P25 was modified with benzoic acid (BA) and 2-naphthalenecarboxylic acid (NCA), and subsequently used to adsorb bisphenol A (BPA). The relationship between the hydrophobicity of the modified TiO2 and the amount of BPA adsorbed was investigated. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Harkins–Jura, and Halsey models. Additionally, TiO2 and TixZr(1-x)O2 of high specific surface area were synthesized via the sol-gel and solvothermal methods. The materials were modified using NCA and used to adsorb BPA. The surface properties of the adsorbent were investigated by Brunauer–Emmett–Teller surface area analysis, Barrett–Joyner–Halenda pore size analysis, CO2 temperature-programmed desorption, and CHN elemental analysis. The specific surface area of TixZr(1-x)O2 (252.1– 455.0 m2/g) was higher than that of TiO2 (157.6 m2/g) and the amount of NCA modified onto TixZr(1-x)O2 (1.106– 1.319 mmol/g) was also higher than that of TiO2 (0.405 mmol/g). The amount of NCA modification onto TixZr(1-x)O2 was promoted by surface base points. The maximum amount of BPA adsorbed was 22.4 mg/L, which was 5.86 times that of TiO2-P25, and approximately 90 % of the BPA was removed from a solution having an initial concentration of 100 mg/L.

Amino-Functionalized Laponite Clay Material as a Sensor Modifier for the Electrochemical Detection of Quercetin.

In this work, an electrode modified with an amino-functionalized clay mineral was used for the electrochemical analysis and quantification of quercetin (QCT). The resulting amine laponite (LaNH2) was used as modifier for a glassy carbon electrode (GCE). The organic–inorganic hybrid material was structurally characterized using X-ray diffraction, Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and CHN elemental analysis. The covalent grafting of the organosilane to the clay backbone was confirmed. The charge on the aminated laponite, both without and with the protonation of NH2 groups, was evaluated via cyclic voltammetry. On the protonated amine (LaNH3+)-modified GCE, the cyclic voltammograms for QCT showed two oxidation peaks and one reduction peak in the range of −0.2 V to 1.2 V in a phosphate buffer–ethanol mixture at pH 3. By using the differential pulse voltammetry (DPV), the modification showed an increase in the electrode performance and a strong pH dependence. The experimental conditions were optimized, with the results showing that the peak current intensity of the DPV increased linearly with the QCT concentration in the range from 2 × 10−7 M to 2 × 10−6 M, leading to a detection limit of 2.63 × 10−8 M (S/N 3). The sensor selectivity was also evaluated in the presence of interfering species. Finally, the proposed aminated organoclay-modified electrode was successfully applied for the detection of QCT in human urine. The accuracy of the results achieved with the sensor was evaluated by comparing the results obtained using UV–visible spectrometry.

Understanding Physicochemical Mechanisms of Sequential Infiltration Synthesis toward Rational Process Design for Uniform Incorporation of Metal Oxides.

Sequential infiltration synthesis (SIS) is a novel technique for fabricating organic–inorganic hybrid materials and porous inorganic materials by leveraging the diffusion of gas-phase precursors into a polymer matrix and chemical reactions between the precursors to synthesize inorganic materials therein. This study aims to obtain a fundamental understanding of the physicochemical mechanisms behind SIS, from which the SIS processing conditions are rationally designed to obtain precise control over the distribution of metal oxides. Herein, in situ FTIR spectroscopy was correlated with various ex situ characterization techniques to study a model system involving the growth of aluminum oxides in poly(methyl methacrylate) using trimethyl aluminum (TMA) and water as the metal precursor and co-reactant, respectively. We identified the prominent chemical states of the sorbed TMA precursors: (1) freely diffusing precursors, (2) weakly bound precursors, and (3) precursors strongly bonded to pre-existing oxide clusters and studied how their relative contributions to oxide formation vary in relation to the changes in the rate-limiting step under different growth conditions. Finally, we demonstrate that uniform incorporation of metal oxide is realized by a rational design of processing conditions, by which the major chemical species contributing to oxide formation is modulated.

Skillful Control of Dispersion and 3D Network Structures: Advances in Functional Organic-Inorganic Nano-Hybrid Materials Prepared Using the Sol-Gel Method.

Organic–inorganic hybrid materials have become indispensable high-performance and highly functional materials. This is owing to the improved dispersion control in hybrid materials and emergence of functional ionic liquids. Harmonization of both these factors has enabled the utilization of functional 3D network structures and nanodispersions in composite materials. Polymeric materials endow materials with flexibility, toughness, and shape-memory properties, whereas inorganic materials provide materials with unique optical, electrical, and magnetic properties due to their nanosize. Organic–inorganic hybrid materials have evolved into novel materials that go beyond the composite rule. In this review, the historical development of hybrid materials prepared using the sol-gel method and the birth of ionic liquids have been summarized. In addition, the historical results leading to the development of functional 3D network structures and dispersion control have also been presented, as well as a review of the research on functional ionic liquids, which are of current interest. The authors also summarize the results of their research on functional ionic liquids. The design of new organic–inorganic hybrid materials has been discussed and the future prospects of new polymer composite materials provided.

Functional mobile-based two-factor authentication by photonic physical unclonable functions

Given the rapid expansion of the Internet of Things and because of the concerns around counterfeited goods, secure and resilient cryptographic systems are in high demand. Due to the development of digital ecosystems, mobile applications for transactions require fast and reliable methods to generate secure cryptographic keys, such as Physical Unclonable Functions (PUFs). We demonstrate a compact and reliable photonic PUF device able to be applied in mobile-based authentication. A miniaturized, energy-efficient, and low-cost token was forged of flexible luminescent organic–inorganic hybrid materials doped with lanthanides, displaying unique challenge–response pairs (CRPs) for two-factor authentication. Under laser irradiation in the red spectral region, a speckle pattern is attained and accessed through conventional charge-coupled cameras, and under ultraviolet light-emitting diodes, it displays a luminescent pattern accessed through hyperspectral imaging and converted to a random intensity-based pattern, ensuring the two-factor authentication. This methodology features the use of a discrete cosine transform to enable a low-cost and semi-compact encryption system suited for speckle and luminescence-based CRPs. The PUF evaluation and the authentication protocol required the analysis of multiple CRPs from different tokens, establishing an optimal cryptographic key size (128 bits) and an optimal decision threshold level that minimizes the error probability.

Unraveling the Organic and Inorganic Passivation Mechanism of ZnO Nanowires for Construction of Efficient Bulk Heterojunction Quantum Dot Solar Cells.

Zinc oxide (ZnO) nanowire (NW) based lead sulfide (PbS) quantum dot solar cells (QDSCs), i.e., bulk heterojunction QDSCs, have been widely investigated because of the excellent photoelectronic properties of PbS QDs and ZnO NWs. To further improve the efficiency of this type of QDSCs, various passivation methods are applied to ZnO NWs to suppress interface recombination caused by trap defects. However, the comparison among passivation using organic, inorganic, and inorganic-organic hybrid materials with different properties has been less studied. In this work, the effect of passivation with inorganic Mg-doped ZnO (ZMO), organic 1,2-ethanedithiol (EDT) and both of them on ZnO NWs and PbS QDSCs are investigated. As a result, ZnO NWs purely passivated by organic material EDT show the best performance with fewer surface defects and better matched energy level with the PbS QD layer. A nearly 1.7 times larger power conversion efficiency (PCE) of 6.9% is achieved for the solar device using ZnO NW @EDT, compared with that (4.1%) of the untreated one. The work provides a promising way to impede interlayer charge recombination and facilitate carrier transport, thus enhancing the photovoltaic performance of the device.

Silica aerogel-filled polymer foams by emulsion-templating: One-pot synthesis, hierarchical architecture and thermal conductivity

The ability of combining different material chemistries to obtain hybrids with a hierarchical architecture is an emerging trend in materials engineering. In this article, we report on co-continuous organic–inorganic macro-mesoporous hybrid materials in which a Si-aerogel network is homogeneously intertwined with a macroporous polymer network, creating an architectural hierarchy. The main thrust of this manuscript is an innovative one-pot synthesis strategy that uses hydrosol-in-oil HIPEs (high internal phase emulsions) as structural templates, where polymerization of monomers in the external phase and hydrolytic condensation of tetramethyl orthosilicate in the internal phase occur simultaneously. The molecular and porous structures as well as thermal and mechanical properties are described and discussed in detail. The resulting multicomponent monoliths yield a hierarchically porous system with pronounced macro-mesoporosity and a specific surface area that increases from 5 m2·g−1 for the bare polyHIPE structure to as high as 242 m2·g−1 for the hybrid structure. The incorporation of Si-aerogel in the polyHIPE lowers its thermal conductivity to 27 mW·m−1·K−1, a value lower than that of commercial high-performance insulators such as superthermally insulating Styrofoam. The Si-aerogel content also affects the mechanical properties. The compressive modulus of the hybrid polyHIPEs increases with Si-aerogel content from 20 MPa for bare polyHIPEs to 98 MPa for the polyHIPEs with the highest Si-aerogel content.

Structural study, Oxytetracycline electrochemical sensing property and molecular docking analysis of a novel synthesized non-centrosymmetric hybrid compound, [formula omitted

A novel non centrosymmetric organic–inorganic hybrid material bis(3-nitrotyrosine) bis(nitrate) (C9H11N2O5)2(NO3)2 denoted 3-NITY-Nitrate has been prepared at room temperature. The crystallographic study shows that the title compound crystallizes in the monoclinic system with P21 space group. Its unit cell dimensions are a = 13.8275 (10) Å, b = 5.7666 (4) Å, c = 15.5280 (12) Å, with V = 1211.11 (18) Å3 and Z = 4. The structure refined to a reliability R factor of 5.42 %. In the present investigation, the stability of crystal was assured by a network of N−H⋯O, O−H⋯O and C−H⋯O hydrogen bonds and through π⋯π and N−O⋯π interactions. The vibrational absorption bands were recorded by IR spectroscopy and have been identified in relation to the crystal structure of a made-up (C9H11N2O5)2(NO3)2 sample. The optical properties of the crystal were studied using UV–visible absorption and photoluminescence spectroscopy. A sensitive electrochemical sensor 3-NITY-Nitrate /GCE membrane was elaborated to detect Oxytetracycline in aqueous solutions. Oxytetracycline electrochemical behavior on the bare GCE and modified 3-NITY-Nitrate/GCE electrodes was studied by cyclic voltammetry. Analytical performance of the proposed sensor-based 3-NITY-Nitrate /GCE for OTC detection from 2*10−7 to 15*10−5 M was investigated using DPV. The limit of detection (LOD) was determined and the characteristics of this 3-NITY-Nitrate /GCE electrode such as reversibility, reproducibility and selectivity are discussed. From the molecular docking studies, it was observed that the organic ligand «3-nitrotyrosine» formed the bis(3-nitrotyrosine) bis(nitrate) (C9H11N2O5)2(NO3)2 fit well in the active site of cyclooxygenase-2.

Experimental and computational investigation of a novel organic cation hexachlorostannate (IV) material (C7H9N2O)2(SnCl6)

A novel organic–inorganic hybrid material (C7H9N2O)2(SnCl6) was obtained by synthetic reaction in aqueous solution. The crystallographic study shows that the investigated compound crystallizes in the triclinic system with P-1 space group. Its unit cell dimensions are a = 7.0859 (7) Å, b = 9.0553 (9) Å, c = 9.1442 (8) Å, a = 81.152(8) Å3, b = 87.126 (8) Å3, c = 67.977 (10) Å3 with V = 537, 43(25) and Z = 2.The three-dimensional framework and the stability of the crystal are insured by N−H⋯Cl, N−H⋯O and C−H⋯O hydrogen bonds and Cg⋯Cg (π⋯π) stacking. The vibrational absorption bands were recorded by IR spectroscopy and have been identified in relation to the crystal structure of a made-up (C7H9N2O)2(SnCl6) sample. The optical properties of the crystal were studied by using UV–visible absorption spectroscopy. The intermolecular interactions occurring in the crystal and their relative contributions in building the solid-state architecture, were quantified by using the three-dimensional Hirshfeld surfaces and two-dimensional fingerprint plots. In addition, the molecular geometries, vibrational frequencies of the compounds in the ground state have been performed using density functional theory (DFT) method, at B3LYP with 6-311g+(2d,2p) set for C, H, N, O, Cl atoms and LANL2DZ basis set for Sn atom.Topological AIM approaches and noncovalent interaction reduced density gradient (NCI-RDG) analyses and were pursued to generate a profound understanding of the structure-directing interactions in the compound. The NBO analysis was carried out to provide information about the delocalization of charge and energy density of atoms.