Search results for "Spectroscopy"
showing 10 items of 10293 documents
Covalent and Ionic Functionalization of HLN Layered Perovskite by Sonochemical Methods
2017
We describe the functionalization of the layered perovskite HLaNb2O7 with n-propanol, n-decanol, 3-mercaptopropyl-trimethoxysilane, imidazole, n-decylamine, and histamine. The use of sonication is found to significantly improve the reaction yield and to reduce the reaction time, compared to conventional thermal treatment under reflux. The obtained intercalates are thoroughly characterized through the use of several complementary experimental techniques (scanning electron microscopy, IR spectroscopy, X-ray diffraction, thermogravimetric analysis, magic-angle spinning NMR), clarifying their structure and chemical bonding. The implications for the design of inorganic–organic composite material…
Copper-, cobalt-, and manganese-containing 17-tungsto-2-germanates.
2009
The sandwich-type tungstogermanates [Cu(3)(H(2)O)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))](12-) (1), [Co(H(2)O)(2){Co(3)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))}(2)](22-) (2), and [Mn(H(2)O)(2){Mn(3)(H(2)O)(B-beta-GeW(9)O(33)(OH))(B-beta-GeW(8)O(30)(OH))}(2)](22-) (3) were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and infrared spectroscopy. Polyanion 1 is composed of two nonequivalent Keggin units, (B-beta-GeW(8)O(31)) and (B-beta-GeW(9)O(34)), linked to each other via three copper(II) ions in such a way that there is a plane of symmetry passing through both Ge atoms and the unique Cu atom, resulting in…
Analysis of archaeological samples and local clays using ICP-AES, TGâDTG and FTIR techniques
2000
Abstract The spectrochemical and thermal analysis of different archaeological samples as bricks, terra-cotta and local clays were carried out. The concentration of major and minor elements of samples was determined by sequential inductively coupled plasma atomic emission spectrometry. The method was tested by determining Si, Al, Fe, Ca, Mg, Mn, Pb, Cu, Zn, Ti, Na and K in the standard solutions and reference material GXR-4. The precision of the determination (relative standard deviation) ranged from 0.4 to 1.54%. The clay minerals are the main materials for the production of bricks and terra-cotta figures. Thermogravimetric (TG) and differential (TG–DTG) analysis and Fourier transform infra…
Tin-based mesoporous silica for the conversion of CO2 into dimethyl carbonate.
2011
Sn-based SBA-15 was prepared by reacting di-n-butyldimethoxystannane with SBA-15 pretreated with trimethylchlorosilane (TMCS) to cap the external hydroxyl groups. Small-angle X-ray diffraction (SXRD), infrared spectroscopy (IR), nitrogen adsorption/desorption, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and inductively coupled plasma atomic emission (ICP-AES) measurements allow us to propose that the organotin species are located within the pore channels of the mesoporous host. This novel material catalyzes selectively the coupling of CO(2) with methanol to dimethyl carbonate (DMC). The reaction time-conversion dependence shows that a turnover number (TON) of 1…
Elaboration of Trans-Resveratrol Derivative-Loaded Superparamagnetic Iron Oxide Nanoparticles for Glioma Treatment
2019
In this work, new nanohybrids based on superparamagnetic iron oxide nanoparticles (SPIONs) were elaborated and discussed for the first time as nanovectors of a derivative molecule of trans-resveratrol (RSV), a natural antioxidant molecule, which can be useful for brain disease treatment. The derivative molecule was chemically synthesized (4&rsquo
Fullerene-ionic-liquid conjugates: a new class of hybrid materials with unprecedented properties.
2015
A modular approach has been followed for the synthesis of a series of fullerene-ionic-liquid (IL) hybrids in which the number of IL moieties (two or twelve), anion, and cation have been varied. The combination of C60 and IL give rise to new unique properties in the conjugates such as solubility in water, which was higher than 800 mg mL(-1) in several cases. In addition, one of the C60 -IL hybrids has been employed for the immobilization of palladium nanoparticles through ion exchange followed by reduction with sodium borohydride. Surprisingly, during the reduction several carbon nanostructures were formed that comprised nano-onions and nanocages with few-layer graphene sidewalls, which have…
Elucidating Gating Effects for Hydrogen Sorption in MFU-4-Type Triazolate-Based Metal-Organic Frameworks Featuring Different Pore Sizes
2011
A highly porous member of isoreticular MFU-4-type frameworks, [Zn(5)Cl(4)(BTDD)(3)] (MFU-4l(arge)) (H(2)-BTDD=bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin), has been synthesized using ZnCl(2) and H(2)-BTDD in N,N-dimethylformamide as a solvent. MFU-4l represents the first example of MFU-4-type frameworks featuring large pore apertures of 9.1 Å. Here, MFU-4l serves as a reference compound to evaluate the origin of unique and specific gas-sorption properties of MFU-4, reported previously. The latter framework features narrow-sized pores of 2.5 Å that allow passage of sufficiently small molecules only (such as hydrogen or water), whereas molecules with larger kinetic diameters (e.…
Oxadiazolyl-pyridines and perfluoroalkyl-carboxylic acids as building blocks for protic ionic liquids: crossing the thin line between ionic and hydro…
2012
A series of 18 samples has been prepared in order to obtain fluorinated materials as Protic Ionic Liquids (PILs). These were synthesized by appropriately mixing 1,2,4-oxadiazoles derivatised with two pyridines, or one pyridine and a fluorinated chain, and perfluoroalkyl-carboxylic acids, either mono- or dicarboxylic, leading to symmetric and non-symmetric materials. Many of them showed low melting points. However, the possibility of classifying the synthesized materials as PILs is discussed in terms of effective ionicity of the systems by the combination of Density Functional Theory (DFT) calculation and IR spectroscopy. The important outcome of our investigation is that the complete proton…
A Straightforward Approach to Multifunctional Graphene
2019
Graphene has been covalently functionalized through a one-pot reductive pathway using graphite intercalation compounds (GICs), in particular KC8 , with three different orthogonally protected derivatives of 4-aminobenzylamine. This novel multifunctional platform exhibits excellent bulk functionalization homogeneity (Hbulk ) and degree of addition while preserving the chemical functionalities of the organic addends through different protecting groups, namely: tert-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz) and phthalimide (Pht). We have employed (temperature-dependent) statistical Raman spectroscopy (SRS), X-ray photoelectron spectroscopy (XPS), magic angle spinning solid state 13 C NMR …
Carbon Nano-onions: Potassium Intercalation and Reductive Covalent Functionalization
2021
Herein we report the synthesis of covalently functionalized carbon nano-onions (CNOs) via a reductive approach using unprecedented alkali-metal CNO intercalation compounds. For the first time, an in situ Raman study of the controlled intercalation process with potassium has been carried out revealing a Fano resonance in highly doped CNOs. The intercalation was further confirmed by electron energy loss spectroscopy and X-ray diffraction. Moreover, the experimental results have been rationalized with DFT calculations. Covalently functionalized CNO derivatives were synthesized by using phenyl iodide and n-hexyl iodide as electrophiles in model nucleophilic substitution reactions. The functiona…