Organic Hybrid Materials Research Articles

Oriented Multiwalled Organic–Co(OH)2 Nanotubes for Energy Storage

AbstractIn energy storage materials, large surface areas and oriented structures are key architecture design features for improving performance through enhanced electrolyte access and efficient electron conduction pathways. Layered hydroxides provide a tunable materials platform with opportunities for achieving such nanostructures via bottom‐up syntheses. These nanostructures, however, can degrade in the presence of the alkaline electrolytes required for their redox‐based energy storage. A layered Co(OH)2–organic hybrid material that forms a hierarchical structure consisting of micrometer‐long, 30 nm diameter tubes with concentric curved layers of Co(OH)2 and 1‐pyrenebutyric acid is reported. The nanotubular structure offers high surface area as well as macroscopic orientation perpendicular to the substrate for efficient electron transfer. Using a comparison with flat films of the same composition, it is demonstrated that the superior performance of the nanotubular films is the result of a large accessible surface area for redox activity. It is found that the organic molecules used to template nanotubular growth also impart stability to the hybrid when present in the alkaline environments necessary for redox function.

Organic/hybrid thin films deposited by matrix-assisted pulsed laser evaporation (MAPLE)

Some of the most exciting materials research in the 21st century attempts to resolve the challenge of simulating, synthesizing, and characterizing new materials with unique properties designed from first principles. Achievements in such development for organic and organic-inorganic hybrid materials make them important options for electronic and/or photonic devices because they can impart multi-functionality, flexibility, transparency, and sustainability to emerging systems, such as wearable electronics. Functional organic materials include small molecules, oligomers, and polymers, while hybrid materials include inorganic nanomaterials (such as zero-dimensional quantum dots, one-dimensional carbon nanotubes, or two-dimensional nanosheets) combined with organic matrices. A critically important step to implementing new electronic and photonic devices using such materials is the processing of thin films. While solution-based processing is the most common laboratory technique for organic and hybrid materials, vacuum-based deposition has been critical to the commercialization of organic light emitting diodes based on small molecules, for example. Therefore, it is desirable to explore vacuum-based deposition of organic and hybrid materials that include larger macromolecules, such as polymers. This review article motivates the need for physical vapor deposition of polymeric and hybrid thin films using matrix-assisted pulsed laser evaporation (MAPLE), which is a type of pulsed laser deposition. This review describes the development of variations in the MAPLE technique, discusses the current understanding of laser-target interactions and growth mechanisms for different MAPLE variations, surveys demonstrations of MAPLE-deposited organic and hybrid materials for electronic and photonic devices, and provides a future outlook for the technique.

A 3-D Wells–Dawson phosphotungstate hybrid material modified by Na+ and a bi-copper organic complex linker, and its photo-/electro-catalytic properties

An inorganic–organic hybrid material based on Dawson polyoxometalates, [Na2{CuI2(bim)2}2(P2W18O62)]·2H2O (bim = biimidazole) (1), has been hydrothermally synthesized and fully characterized. In 1, each {P2W18} cluster as a hexa-node ligand connects to six adjacent Dawson clusters via six Na1 ions to generate a pure inorganic 2-D layer, further joined by bimetal–organic segments [Cu2(bim)2]2+ to form a 3-D inorganic–organic hybrid framework with channels. The structure can be simplified to 3,8-connected 3-D networks with (43)(418·624·83) topology, which shows bifunctional electrocatalytic performance for oxidation of ascorbic acid (AA) and reduction of nitrite (NO2−), and high-efficient degradation ability for three typical dyes under UV light irradiation.

Synthesis of graphene oxide/metal–organic frameworks hybrid materials for enhanced removal of Methylene blue in acidic and alkaline solutions

AbstractBACKGROUNDDye wastewater is causing a serious problem to the environment and to human health. A considerable amount of colored wastewater is generated from many industries. Moreover, many dyes in the wastewater are believed to be toxic and even carcinogenic. Therefore, the removal of dyes from wastewater is necessary and urgent.RESULTSThe adsorption kinetics, isotherms and intra‐particle diffusion model were determined from experimental data, and the results indicated that the pseudo‐second‐order kinetic model and the Langmuir adsorption isotherm matched well the adsorption of MB onto GO/MOFs. Thermodynamic parameters revealed that the adsorption of MB by GO/MOFs was spontaneous and exothermic. The adsorption capacity was greatly improved in acidic or alkaline aqueous solution. The maximum adsorption capacity of GO/MOFs reached 274 mg g‐1, higher than most previously reported adsorbents. Also, the adsorbent could be used at least five times after washing with ethanol.CONCLUSIONA microwave‐assisted ball milling method was used successfully to synthesize Ni‐MOFs and GO/MOFs. Because of electrostatic interaction and acid–base interaction, both acidic and alkaline aqueous solutions were found to favor the adsorption of MB by GO/MOFs, this being different from previous reports. GO/MOFs also showed acceptable reusability after being regenerated by ethanol. All the results suggest that MOFs prepared by microwave‐assisted ball milling give the prospect of removal of MB from aqueous solution. © 2017 Society of Chemical Industry

Charge carrier localised in zero-dimensional (CH3NH3)3Bi2I9 clusters

A metal-organic hybrid perovskite (CH3NH3PbI3) with three-dimensional framework of metal-halide octahedra has been reported as a low-cost, solution-processable absorber for a thin-film solar cell with a power-conversion efficiency over 20%. Low-dimensional layered perovskites with metal halide slabs separated by the insulating organic layers are reported to show higher stability, but the efficiencies of the solar cells are limited by the confinement of excitons. In order to explore the confinement and transport of excitons in zero-dimensional metal–organic hybrid materials, a highly orientated film of (CH3NH3)3Bi2I9 with nanometre-sized core clusters of Bi2I93− surrounded by insulating CH3NH3+ was prepared via solution processing. The (CH3NH3)3Bi2I9 film shows highly anisotropic photoluminescence emission and excitation due to the large proportion of localised excitons coupled with delocalised excitons from intercluster energy transfer. The abrupt increase in photoluminescence quantum yield at excitation energy above twice band gap could indicate a quantum cutting due to the low dimensionality.

Photo and Thermal Cured Silicon‐Containing Diethynylbenzene Fibers via Melt Electrospinning with Enhanced Thermal Stability

ABSTRACTAn inorganic–organic hybrid material, poly(dimethylsilylene ethynylenephenyleneethynylene) (PMSEPE), was synthesized in a mild condition and its microfiber was successfully produced by melt electrospinning. The electrospinning parameters, which affected the morphology and diameter of fibers, were well investigated. To maintain the fiber structure at thermal cured temperature (above melting point), the PMSEPE fibers were enhanced via thiol‐yne photo polymerization. Followed by the thermal curing reaction, the heat‐resistance and mechanical properties of fibers were enhanced. The mechanism of two‐step curing was explored and confirmed by means of Fourier transform infrared, differential scanning calorimetry, and X‐ray photoelectron spectroscopy (XPS). Thermaogravimetric analysis and scanning electron microscopy results show that after carbonization at 800 °C, the two‐step cured fibers had only a small weight loss (20%) and the fibers can still maintain the original morphology. Moreover, the two‐step cured fiber exhibited a high tensile strength (55.4 MPa) and a small elongation at break (0.02%). All the results indicate that the fibers could be applied as fiber‐reinforced materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2815–2823

Design of nucleic acid-layered double hydroxide nanohybrids

We report here on the design of inorganic–organic hybrid materials, which consist of layered double hydroxides (LDHs) as inorganic carrier and short single-stranded nucleic acids (ssDNA) as organic molecules. LDHs were prepared by the co-precipitation method followed by hydrothermal treatment. A model 12-nucleotide-long sequence was immobilized either by ion exchange or covalent grafting. Both the LDH composition and the nucleic acid-to-particle ratio were optimized throughout the synthesis to develop highly stable suspensions of the hybrid materials. Structural characterization revealed that the covalent attachment of the ssDNA was successfully achieved via silanization of the LDHs in aqueous suspension. Covalent linkage of the nucleic acids confers to this model nanoparticulate system promising properties and potential for applications as therapeutic agents. Fragments of nucleic acids could be introduced into living cells without release during the delivery process since LDHs slowly dissolve in the slightly acidic intracellular space.

Dual Functionality of TiO2/Biochar Hybrid Materials: Photocatalytic Phenol Degradation in the Liquid Phase and Selective Oxidation of Methanol in the Gas Phase

A series of new inorganic–organic hybrid materials based on TiO2 and new biochar-based supports (biochar obtained by pyrolysis of miscanthus straw pellets (MSP) and soft wood pellets (SWP) at 550 and 700 °C) were successfully prepared using ultrasound-assisted methodology. The resulting composites were characterized by a wide range physicochemical techniques and investigated in water and gas-phase photocatalytic test reactions. Our best composite (TiO2/SWP700) achieved phenol degradation of 64.1% (under UV light) and 33.6% (under visible light). In addition, it also showed an extraordinarily high activity (∼90%) in selective oxidation of methanol to methyl formate in flow gas phase, high selectivity to methyl formate (∼80%), and high yield of methyl formate (∼88%) after 240 min of illumination. It can be noticed that when TiO2 is supported on biochar it presented a superior photocatalytic ability and could be recycled at least 5 times in both photocatalytic runs tests with reproducible high photocatalytic...

Nature‐Inspired Synthesis of Nanostructured Electrocatalysts through Mineralization of Calcium Carbonate

Biomineralization is a biogenic process that produces elaborate inorganic and organic hybrid materials in nature. Inspired by the natural process, this study explored a new mineralization approach to create nanostructured CaCO3 films composed of amorphous CaCO3 hemispheres by using catechol-rich polydopamine (PDA) as a biomimetic mediator. The thus synthesized biomimetic CaCO3 was successfully transformed to nanostructured films of metal-oxide minerals, such as FeOOH, CoCO3 , NiCO3 , and MnOOH, through a simple procedure. The CaCO3 -templated metal-oxide minerals functioned as efficient electrocatalysts; a CaCO3 -templated cobalt phosphate (nanoCoPi) film exhibited high stability as a water-oxidation electrocatalyst with a current density of 1.5 mA cm-2 . The nanostructure of nanoCoPi, consisting of individual nanoparticles (≈70 nm) and numerous internal pores (BET surface area: 3.17 m2 g-1 ), facilitated an additional charge-transfer pathway from the electrode to individual active sites of the catalyst. This work demonstrates a plausible strategy for facile and green synthesis of nanostructured electrocatalysts through biomimetic CaCO3 mineralization.

Density functional theory study of interactions between carbon dioxide and functionalized polyhedral oligomeric silsesquioxanes

AbstractPolyhedral Oligomeric Silsesquioxanes (POSS) are cage‐structured inorganic–organic hybrid materials which can be used in various industrial applications. It is recently discovered that POSS structures with certain functional groups can be solubilized in supercritical CO2 allowing their applications in environmentally benign supercritical processing of materials. In this theoretical study, nature and energetics of the interactions of octatrifluoropropyl POSS, octatrifluoromethyl POSS, and octamethyl POSS with CO2 are investigated according to the principles of density functional theory (DFT) by use of Gaussian 09 software. Simulations show that CO2‐octamethyl POSS pair has hydrogen bonding between the O atom of CO2 and the H atom of the methyl group, and CO2‐octatrifluoromethyl POSS pair has interactions between the C atom of CO2 and the F atom of the trifluoromethyl group. CO2‐octatrifluoropropyl POSS pair is found to have both interaction types. The octamethyl, the octatrifluoromethyl and the octatrifluoropropyl POSS structures have interaction energies of −2.18 kcal/mol, −3.10 kcal/mol, and −3.77 kcal/mol, respectively. This shows that the presence of Lewis acid–Lewis base interaction between C and F instead of hydrogen bonding between O and H atoms enhances the interaction of the molecule with CO2, while the presence of both interactions between the octatrifluoropropyl POSS‐CO2 pair makes the intermolecular interaction even stronger.

Chemo-Electrical Gas Sensors Based on Conducting Polymer Hybrids.

Conducting polymer (CP) hybrids, which combine CPs with heterogeneous species, have shown strong potential as electrical transducers in chemosensors. The charge transport properties of CPs are based on chemical redox reactions and provide various chemo-electrical signal transduction mechanisms. Combining CPs with other functional materials has provided opportunities to tailor their major morphological and physicochemical properties, often resulting in enhanced sensing performance. The hybrids can provide an enlarged effective surface area for enhanced interaction and chemical specificity to target analytes via a new signal transduction mechanism. Here, we review a selection of important CPs, including polyaniline, polypyrrole, polythiophene and their derivatives, to fabricate versatile organic and inorganic hybrid materials and their chemo-electrical sensing performance. We focus on what benefits can be achieved through material hybridization in the sensing application. Moreover, state-of-the-art trends in technologies of CP hybrid sensors are discussed, as are limitations and challenges.

Beyond Equilibrium: Metal–Organic Frameworks for Molecular Sieving and Kinetic Gas Separation

Metal–organic frameworks (MOFs) are a class of crystalline inorganic–organic hybrid materials that have demonstrated huge potential in gas separation due to their ultrahigh porosity, boundless chemical tunability, as well as surface functionality. Most gas separations realized in MOFs are under an equilibrium state and are dependent on the difference in thermodynamic affinities of gases to MOFs, whereas nonequilibrium separation such as kinetic and molecular sieving separation attracting growing attention in the past decade is achieved based on the difference in the size and diffusivity of gas molecules. In this perspective, we first discuss the pore size, temperature, and pressure effect on gas diffusion as well as nonequilibrium gas separation in MOFs. Second, we introduce current techniques reported to measure intracrystalline gas diffusivity. Third, we review recent progress in MOF-based nonequilibrium N2/O2 separation, CO2 capture, and hydrocarbon separation. In addition, we describe the hydrogen iso...

Atomic/molecular layer deposition of hybrid inorganic–organic thin films from erbium guanidinate precursor

Luminescent erbium-based inorganic–organic hybrid materials play an important role in many frontier nano-sized applications, such as amplifiers, detectors and OLEDs. Here, we demonstrate the possibility to fabricate high-quality thin films comprising both erbium and an appropriate organic molecule as a luminescence sensitizer utilizing the combined atomic layer deposition and molecular layer deposition (ALD/MLD) technique. We employ tris(N,N′-diisopropyl-2-dimethylamido guanidinato)erbium(III) [Er(DPDMG)3] together with 3,5-pyridine dicarboxylic acid as precursors. With the appreciably high film deposition rate achieved (6.4 A cycle−1), the guanidinate precursor indeed appears as an interesting new addition to the ALD/MLD precursor variety toward novel materials. Our erbium–organic thin films showed highly promising UV absorption properties and a photoluminescence at 1535 nm for a 325-nm excitation, relevant to possible future luminescence applications.

Asymmetric Michael addition catalyzed by a cinchona alkaloid derivative non-covalently immobilized on layered inorganic supports

A study on the asymmetric Michael addition of a fluorine containing carbon nucleophile to β-nitrostyrene was carried out to find an easily obtainable cinchona alkaloid derivative, which provides high stereoselectivities, and may be conveniently immobilized over inorganic materials to obtain efficient chiral heterogeneous catalysts. It was shown that high enantioselectivities are reached in the addition of ethyl 2-fluoroacetoacetate catalyzed by β-isocupreidine accompanied by good diastereomeric ratios. This cinchona derivative prepared in one step from quinidine was immobilized by cation-exchange between the layers of an aluminum phyllosilicate, as evidenced by XRD measurements. However, due to the protonation of the tertiary amino group, the material lost its catalytic activity in the Michael addition. The immobilization of the deprotonated alkaloid over the particle surface of an anion exchanger layered double hydroxide resulted in an inorganic–organic hybrid material, with catalytic performance approaching that of the soluble organocatalyst. Upon reuse, gradual deactivation of this heterogeneous catalyst was observed due to the leaching of the organic material. However, using less polar media could increase the lifetime of the hybrid catalyst. The results of catalytic measurements indicated that the Michael addition might occur on the solid surface. Based on the catalytic behavior of the heterogeneous catalyst, bonding possibilities of the cinchona derivative to the surface of the layered hydroxide by electrostatic interactions and hydrogen bonding are suggested.

Terpyridine-Functionalized NanoSiO2 Multi-Dentate Linkers: Preparation, Characterization and Luminescent Properties of Their Metal–Organic Hybrid Materials

Terpyridine- (TPy-) functionalized silica nanolinkers (nanoSiO2–TPy) have been prepared and used as nanoscale multidentate ligands to coordinate with the transition metal ions (Mn+ = Zn2+, Fe2+, Tb3+ and Eu3+) for producing luminescent metalated organic–inorganic nanoSiO2–TPyM hybrid materials. Thermogravimetric analysis has revealed that the covalently attached organic species in the nanoSiO2–TPy linkers were about 10% in weight. After they were functionalized with the layers of TPy or TPyM, the as-prepared nanoSiO2–TPy linkers and nanoSiO2–TPyM hybrids formed aggregates more easily due to an increase of internanoparticle interactions. The ζ-potential of the nanoSiO2–TPy linkers was about 34.6 mV, which increased to 55 to 60 mV for the nanoSiO2–TPyM hybrids in the poly(ethylene glycol) 200 (PEG 200) solutions. Under UV radiation, the nanoSiO2–TPy linkers gave off an emission at about 366 nm (monomer of the linkers) in the PEG 200 solutions with the concentrations below 0.5 mg/mL, which shifted to 374 nm ...

Via precise interface engineering towards bioinspired composites with improved 3D printing processability and mechanical properties.

Precise interface engineering in inorganic-organic hybrid materials enhances both the elastic moduli and toughness of a biodegradable composite, which is of relevance for load-bearing applications in bone tissue engineering. Tailor-made MgF2-binding peptide-polymer conjugates (MBC) are utilized as precision compatibilizers, having sequence-specific affinity for the surfaces of the inorganic MgF2 fillers to stabilize these particles and to contribute to the interactions with the continuous polymer matrix. The effects of the coupling agents are investigated in additively biomanufactured scaffolds from composites composed of MBC compatibilized magnesium fluoride nanoparticles (cMgF2) and poly(ε-caprolactone). Mechanical properties, degradation behavior, ion release kinetics and in vitro cell viability are positively influenced by the presence of the compatibilized nanoparticles cMgF2 compared to pure, non-compatibilized MgF2 (pMgF2). Mechanical tensile, compression and indentation experiments with single filaments as well as with scaffolds a reveal strong improvement of both elastic moduli and material toughness.

A long-range emissive mega-Stokes inorganic-organic hybrid material with peripheral carboxyl functionality for As(v) recognition and its application in bioimaging.

We demonstrate a strategy for the recognition of As5+ in aqueous solution using a red-emissive probe based on a perylene-Cu2+ ensemble decorated with peripheral free carboxyl functionality. Single crystal analysis helped us to understand the chemical structure of the probe. To the best of our knowledge, this is the first probe for arsenic detection which emits in the red region (λem = 600 nm). The perylene-Cu2+ ensemble exhibited a mega-Stokes shift (>100 nm) with a high degree of selectivity upon interaction with As5+, which indicated that the present probe has the potential to be used as a turn-on optical sensor for selective detection of As5+ with fewer experimental limitations. The detection limit was found to be 26 nM. Inspired by its good emissive properties, the ensemble was further explored for imaging As5+ in live cells. Because of its long-range emissive nature, no autofluorescence from the cellular species was observed during the imaging process. The probe was evaluated to be non-toxic and successfully permeated the cell membrane without the help of any permeabilizing agent to image As5+.

Methoxy-grafted kaolinite preparation by intercalation of methanol: Mechanism of its structural variability

Methoxy-grafted kaolinite is an excellent organic-inorganic compound, which serves as a precursor to prepare new organic or inorganic kaolinite hybrid materials. Direct intercalation of kaolinite with dimethyl sulfoxide (DMSO), N-methylformamide (NMF) and urea (U) was achieved. All of the above intercalated kaolinites could be grafted by methoxy groups by reacting with methanol. The pre-intercalated molecules of DMSO, NMF and U blocked the grafting action at first but facilitated it at a later stage. Here, the mechanism of the structural collapse of methoxy-grafted kaolinite was proposed. Spontaneous deintercalation of small molecules such as water, ethanol, isopropanol and others was observed. Water and methanol molecules played an important role in the grafting action and also affected the structure of methoxy-grafted kaolinite. The d(001) of methoxy-grafted kaolinite was found to be in the range of 0.99–1.11nm in wet state but constant at 0.86nm for dry state. 13C CP/MAS NMR analysis confirmed that inner-surface hydroxyls were replaced by methoxy groups from methanol as detected by a 13C MASNMR resonance at 51ppm assigned to methoxy groups. 13C MASNMR spectra of intercalated kaolinites confirmed that the pre-intercalated molecules were not displaced completely even though it cannot be detected by XRD. The hygroscopicity of the pre-intercalated molecules was found to affect the structure of methoxy-grafted kaolinite.

New Inorganic–Organic Hybrid Materials and Their Oxides for Removal of Heavy Metal Ions: Response Surface Methodology Approach

In this paper, Cu(II), Fe(III), Pb(II), and Zn(II) heavy metal ions were removed from their aqueous solutions by using novel inorganic–organic hybrid materials, Al-GPTS-H and Al-GPTS-NaOSiMe3-H (hybrid material-1 and 2, respectively), and their oxides (calcined-1 and 2) as adsorbents. These ions removal by adsorption was optimized by using response surface methodology (RSM). Central composite design (CCD) method was used in order to investigate the effects of initial pH, initial metal concentration of solutions and adsorbent quantity on the adsorption efficiency (R, %). As a result of the experiments under optimum conditions, the maximum % R values were obtained by hybrid material-1 for Fe(III) (99.89%) and by calcined material-1 for Pb(II) (97.14%), respectively. These quite high adsorption efficiency values have shown that these hybrid materials and their oxides are suitable to use for heavy metal ions removal from aqueous solutions.

MIL-100(V) and MIL-100(V)/rGO with various valence states of vanadium ions as sulfur cathode hosts for lithium-sulfur batteries

MIL-100(V) is an inorganic–organic hybrid material composed of trimesic acid ligands and vanadium trimer supertetrahedra. MIL-100(V) is expected to be a good host for sulfur impregnation and an excellent sulfur cathode host for Li-S batteries, not only because of its unique mesoporous structure, but also owing to the presence of vanadium ions with various valence states, which can offer different Lewis acid sites and allow for strong interactions with sulfur and lithium polysulfides. In this study, mesoporous MIL-100(V) and MIL-100(V)/reduced graphene oxide (rGO) composites have been applied as novel hosts for Li-S batteries for the first time. When tested as cathodes for Li-S batteries, both S@MIL-100(V) and S@MIL-100(V)/rGO exhibit excellent electrochemical performance. The S@MIL-100(V) cathode has been demonstrated to have a reversible capacity of ~550 mAh/g at 0.1 C (1 C = 1,675 mAh/g) after 200 cycles with low capacity fading of 0.17% per cycle. Moreover, S@MIL-100(V)/rGO maintains a capacity of 650 mAh/g at 0.1 C after 75 cycles, whereas at 0.5 C, the capacity is maintained at 500 mAh/g after 200 cycles and 450 mAh/g after 300 cycles. The above results reveal that the use of MIL-100(V) and MIL-100(V)/rGO as hosts for Li-S batteries can effectively enhance the cycling stability and improve the electrochemical performance of Li-S batteries.