Formulation of Mechanochemically Evolved Fly Ash Based Hybrid Inorganic–Organic Geopolymers with Multilevel Characterization

In this research, advanced hybrid inorganic–organic geopolymeric material is developed by environmentally and user friendlier approach. The presented novel approach for geopolymer formation certainly overcomes the existing drawbacks of geopolymerization technology. The effect of rice husk ash and Na₂O/SiO₂ ratios on geopolymer gel formation and mechanical strength has been previously identified via solution chemistry route; however, development of geopolymeric material having hybrid inorganic–organic characters via together mechanochemical grinding of raw materials and effect of mechanochemically activated Na₂SiO₃ on geopolymeric properties via solid state route has never before been explored. Together mechanochemical grinding of raw materials of varying compositions in solid state resulted in the formation of ready to use geopolymeric precursors; which on just addition of water led to development of advanced hybrid inorganic–organic geopolymeric material with considerably enhanced properties. XRD, FTIR and SEM characterization data of developed geopolymeric precursor powder and hybrid inorganic–organic geopolymeric material are reported and discussed in detail. As the results of the investigations, the relationship between geopolymer composition, grinding mechanism and material properties established. The composition which exhibited synergistic effect of both rice husk and SMS is found to be excellent in performance. The study showed that it is practical and better to adopt this greener solid state approach for preparation of geopolymer instead of user-unfriendlier hazardous alkaline solution based approach, to achieve sustainable growth in geopolymers as like Portland cement.     

Self-Assembled Organic–Inorganic Hybrid Nanocomposite of a Porphyrin Derivative and CdS

A porphyrin derivative, 5-(4-carboxylphenyl)-10,15,20-tris(4-chlorophenyl) porphyrin (PorCOOH), was synthesized and self-assembled as a monolayer thin solid film on the modified surface of a quartz substrate by an ester bond between –COOH groups of PorCOOH molecules and –OH groups of the hydrophilic pretreated SiO₂ surface. An analysis of the spectral change revealed the J-aggregate nature of PorCOOH molecules in the obtained thin solid film. With this thin solid film of PorCOOH as a template, CdS nanoparticles were deposited on it in situ, which were further characterized by electronic absorption, fluorescence, and energy-dispersive X-ray spectroscopy. The morphology of CdS nanoparticles is disklike, and the diameter is ca. 40–60 nm, determined by scanning electronic microscopy. Furthermore, electron transfer between the organic layer and CdS nanoparticles was deduced through fluorescence quenching and theoretical analysis.     

Synthesis,Characterization, Luminescent and Thermal Properties of a Hybrid Inorganic–Organic Polymeric Framework Formed by Lead (II) Pyridinecarboxylate

Abstract  

A coordination polymer of formula [Pb_0.5(pyc)] _n , 1, where Hpyc = pyridine-3-carboxylic acid, has been synthesized and structurally characterized by X-ray single crystal diffraction analysis. Every Pb(II) centre demonstrate trigonal dodecahedron geometry. The ligand i.e. pyridine-3-carboxylate offers μ _{3 -} η ² : η ¹ coordination pattern using its hetero donor centres. The complex initially forms an infinite 1D chain (c-axis) which is turned to 2D sheet and finally a 3D network is recognized through ligand connectivity. Stabilization of 3D structure is further reinforced by π–π stacking interaction. An open channel is identified along c-axis. TG analysis has been performed for the complex. Emission study demonstrates the existence of intraligand and metal-to-ligand charge transfer transition in 1.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Property of Two Inorganic–Organic Hybrid Frameworks via Hydrogen Bonding

Two inorganic–organic hybrid frameworks, namely [Cu₂(pdca)₂(bibp)(H₂O)₂]·H₂O (1) and [Fe(pdca)(pyco)(H₂O)]·H₂O (2) (H₂pdca = pyridine-2,6-dicarboxylic acid, bibp = 4,4′-bisimidazolylbiphenyl, pyco = picolinate N-oxide) were synthesized via hydrothermal reactions. Both compounds have been characterized by elemental analysis, spectroscopic analysis, thermogravimetric analysis (TGA) and the single crystal diffraction. Complex 1 is dinuclear and five-coordinated copper(II) complex, while complex 2 displays mono-nuclear and six-coordinated iron(III) complex. In the crystal structures of both complexes, the coordinated and crystalline water molecules and H₂pdca ligands contribute to the formation of O–H···O and C–H···O hydrogen bonds, which link the molecules into layers parallel. Cyclic voltammetry (CV) analysis shows one reversible reduction potential at 0.14 V (E_pc) in complex 1, whereas in complex 2 shows a reduction potential at 0.15 V (E_pc) in the cathodic region.     

One-Step Hydrogenation/Esterification Activity Enhancement Over Bifunctional Mesoporous Organic–Inorganic Hybrid Silicas

Bifunctional mesoporous organic–inorganic hybrid silica incorporating both platinum and organosulfonic acid groups were synthesized for use in simultaneously catalyzing the one-step hydrogenation/esterification (OHE) of acetic acid and acetaldehyde, which was considered as a model reaction for the upgrading of biomass-derived bio-oil. The work explored optimizing the synthesis procedure to generate a bifunctional catalyst with enhanced combined activity for the OHE reaction. The presence of Pt was found to enhance the acidic properties of the organosulfonic acid functionalized silica. The mechanism by which the Pt incorporation affected the acid sites was investigated by the using XPS, FT-IR, FT-Raman characterization. The XPS results indicated the presence of electron transfer between the Pt and –SO₃H groups. The FT-IR and FT-Raman results, which were in agreement with XPS, demonstrated an electron density increase for S and a S–O bond energy increase, which was proposed to be the reason for the acidity enhancement due to the presence of Pt. Additionally, arenesulfonic acid groups were substituted for propylsulfonic acid groups and the resulting material had higher catalytic activity due to the increased acid strength. An optimal synthesis procedure was demonstrated in which the Pt was first impregnated on the mesoporous silica using reductive deposition. Then Pt was activated and the material further modified by grafting on arenesulfonic acid groups. The resulting catalyst was about four times more active than the original base case bifunctional material.     

Ionothermal Syntheses and Crystal Structures of Two 1D Inorganic–Organic Hybrid Frameworks

Two 1D inorganic–organic hybrid frameworks, namely, [Zn(5-NO₂-bdc)(MIM)₃·H₂O]_n(1) and [Cd(MIM)₂Br₂]_n(2) (5-NO₂-bdcH₂ = 5-nitro-1,3-benzenedicarboxylic acid, MIM = N-methyl imidazole) were synthesized via ionothermal reactions with ionic liquid 1-ethyl-3-methylimidazolium bromide ([EMIM]Br) as solvent and template. Both compounds have been characterized by elemental analyses, spectroscopic analyses, thermogravimetric analysis (TGA) and the single crystal diffraction. The zinc(II) center in compound 1 is a slightly distorted five-coordinate trigonal bipyramid, 5-NO₂-bdc²⁻ anions and MIM moieties effectively bridge Zn centers to result in 1D zigzag chains. While Cd(II) center in compound 2 is in an octahedral coordination environment, and two μ²-bridge bromine link two [Cd(MIM)₂] moieties to form a 1D chain structure. In addition, complex 2 exhibits strong fluorescent emission in the solid state at room temperature.     

Inorganic–Organic Hybrid Materials of Zirconium and Aluminum and Their Usage in the Removal of Methylene Blue

Two novel inorganic–organic hybrid materials, Al-Pydca-3-APDEMS-H and Zr-Pydca-3-APDEMS-H, were prepared by the sol gel method in two steps. In the first step, Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca complexes were prepared from the reactions of aluminum sec-butoxide Al(O^sBu)₃ and zirconium n-propoxide Zr(OPrⁿ)₄ with 2,6-pyridinedicarboxylic acid, respectively. After 3 h of stirring, 3-aminopropyldiethoxymethyl silane (3-APDEMS) and dilute hydrochloric acid were added to the Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca mixtures to hydrolyze the reactions and to form condensation products. These hybrid products were characterized by a combination of Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) and other analysis methods. These hybrid materials were used for the removal of methylene blue (MB), a cationic organic dye. The removal efficiency of hybrid materials was measured by UV–Vis spectroscopy.

     

An Organic–Inorganic Hybrid Composite as a Coating Agent

An organic–inorganic hybrid composite for use as a coating agent was prepared by mixing linseed oil with hydrophobic octylsilyl titanium dioxide particles having an average diameter of 35 nm (OSI-TIO2-35) in volatile silicone. The weight ratio of linseed oil with OSI-TIO2-35 was varied from 2:8 to 8:2 and the mixture was spread on a glass plate by dragging an applicator across it. After storing in the oven at 60 °C for 2 days, the composite having the weight ratio of OSI-TIO2-35 with linseed oil at 8:2 exhibited very high water-repellent properties having a water contact angle of 148°. Variation of the water contact angle during storage at 60 °C was monitored. It decreased by 10° in the initial 8 h and then increased by 45° over the next 2 days. Composites containing silicone resin, TMSS BY11-018, instead of linseed oil were also prepared. The sample having a weight ratio of OSI-TIO2-35 with TMSS BY11-018 at 8:2 also exhibited very high water-repellent properties with a water contact angle of 152°. The highly hydrophobic surface thus prepared by the coating and drying of those organic-inorganic hybrid composites was easily transferred to highly hydrophilic surfaces by calcination at 500 °C for 3 h.     

Organic–Inorganic Incompletely Condensed Polyhedral Oligomeric Silsesquioxane-Based Nanohybrid: Synthesis,Characterization and Dye Removal Properties

A nanocomposite was developed from organic–inorganic hybrid of incompletely condensed polyhedral oligomeric silsesquioxane nanoparticles and poly (acrylamide-co-hydroxyethyl methacrylate) with properties of hydrophobicity of incompletely condensed polyhedral oligomeric silsesquioxane and dye adsorption capacity of the copolymer. The as-prepared nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The synthesized hybrid nanocomposite acquires extraordinary water remediation property after the removal of toxic dye from aqueous solution. Conditions for the adsorption of dye by the hybrid nanocomposite have been also optimized. In addition, the adsorption mechanism was studied.     

Synthesis and Characterization of Hybrid Core–Shell Systems Based on Molecular Silicasols

New hybrid “rigid inorganic core–soft organic shell” systems based on molecular silicasols were synthesized by applying different synthetic schemes. Inorganic core was composed of molecular silicasols, which were synthesized from hyperbranched polyethoxysiloxane and tetraethoxysilane by polymer chemistry methods. Different organic modifiers were used to form soft shell of the hybrid particles. Obtained compounds were characterized by elemental analysis, GPC, IR and NMR spectroscopy. These systems will be designated for use as model objects for investigation of nanoparticles–polymer matrix interactions in polymer nanocomposites.     

Synthesis, Characterization and HDS Activity of Carbon-Containing Ni–Mo Sulfide Nano-Spheres

Ni-promoted tetramethylammonium tetrathiomolybdate precursor was prepared by the aqueous solution precipitation method using (NH₄)₂MoS₄, (CH₃)₄NBr and NiCl₂.6H₂O as raw materials. Carbon-containing Ni–Mo sulfide nanospheres, namely Ni/C₁–MoS₂, were obtained by ex situ thermal decomposition of the precursor under N₂ atmosphere. Energy dispersive X-ray spectroscopy (EDS), low temperature N₂ adsorption (BET method), X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) techniques were employed to characterize these as–synthesized sulfide particles. The results showed that the average size of solid Ni–Mo sulfide nanospheres, with surface composition MoNi₀.₄₀S₀.₇₃C₁.₄₃, is 75 nm and the solid structure leads to low surface area of Ni/C₁–MoS₂. In addition, the introduction of methyl chain improved the dispersion of nickel phases and resulted in C/Mo ratio, 1.4. By comparison with catalytic performance of the Ni/MoS₂ catalyst counterpart, Ni/C₁–MoS₂ revealed lower HDS activity but higher direct desulfurization (DDS) selectivity. Lower stacking number of MoS₂ slabs (5 layers) and shorter slabs length of MoS₂ slabs (6 nm) explained higher DDS selectivity satisfactorily. The formation of carbon-containing Ni–Mo sulfide nanospheres was possibly due to surfactant effect of tetramethylammonium cations and the potential measure to increase their surface area was discussed as well in this work.     

Synthesis and Evaluation of Nifurtimox–Adamantane Adducts with Trypanocidal Activity

The synthesis and pharmacological evaluation of C1-substituted adamantane hydrazones, their C2-substituted isomers, and C1-substituted adamantane furanoic carboxamides is described. These new adamantane derivatives exhibited an interesting pharmacological profile in terms of trypanocidal activity and selectivity. The most active adduct with the best selectivity in this study was found to be the phenylacetoxy hydrazone 1 b (2-[4-(tricyclo[3.3.1.1^3,7]dec-1-yl)phenyl]-N′-[(5-nitrofuran-2-yl)methylene]acetohydrazide; EC₅₀=11±0.9 nm , SI_Tb=770).     

An Efficient and Recyclable Silica Based Inorganic–Organic Hybrid Zinc Catalyst for Transesterification of β-Ketoesters

A new silica based inorganic–organic hybrid zinc catalyst was synthesized and its catalytic activity was investigated for transesterification of β-ketoesters. Polymer supported catalyst was characterized by various techniques such as surface area (BET), elemental and thermogravimetric analyses, FTIR, ¹³C CPMAS spectral studies and atomic absorption spectroscopy (AAS). The reaction proceeded smoothly in the presence of 0.04 mmol of catalyst in toluene at refluxing conditions. The catalyst revealed higher catalytic activity compared to homogeneous catalyst and was reused without appreciable loss in catalytic activity.     

Syntheses and Crystal Structures of Two Inorganic–Organic Hybrid Frameworks Constructed from Pyridine-2,5-Dicarboxylic Acid

Two novel inorganic–organic hybrid frameworks of [Co(2,5-pydc)(4,4′-bipyo)_0.5(H₂O)₃ · 3H₂O] _n (1) and [Cu_1.5Gd(2,5-pydc)₃(2,2′-bipyo)(H₂O)₄ · 2H₂O] _n (2) (2,5-pydc = pyridine-2,5-dicarboxylic acid; 4,4′-bipyo = 4,4′-bipyridine-N,N′-dioxide; 2,2′-bipyo = 2,2′-bipyridine-N,N′-dioxide) were prepared. Both compounds have been characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. The salient structural feature for both compounds 1 and 2 is that the 1D chain and the mononuclear fragment are connected by strong hydrogen bond interactions to form 2D structure.     

Ladder-Like Versus Hexagonal Organic–Inorganic Hybrid Materials in the Extraction of Lead Ions

Meso-structured and ladder organic–inorganic hybrid materials functionalized with ammonium carboxylate groups were prepared. These materials were obtained by the sol–gel process starting from the cyanopropyltriethoxysilane precursor as a building block. Hydrolysis of CN to COOH groups followed by treatment with triethylamine gives rise to cationic exchange materials. These materials exhibit a high chelating capability towards cations and can be used for water treatment. Lead ion (Pb²⁺) was tested as example; and, some tests were made on the meso-structured and ladder material for further comparison in efficacy of extractions.