The steps of thermal treatment of Na-magadiite: a computational study using DFT calculations.

We investigated each of the successive transformations of this material using calculations based on DFT. Possible structures produced from three reaction steps of the thermal treatment were simulated. Thermodynamic analysis was performed to assess the energy stability of each reaction.

Introduction to celebrating Latin American talent in chemistry.

In celebration of the excellence and breadth of Latin American research achievements across the chemical sciences, we are delighted to present an introduction to the themed collection, Celebrating Latin American talent in chemistry.

Protected areas' effectiveness under climate change: a latitudinal distribution projection of an endangered mountain ungulate along the Andes Range.

Background: Climate change is one of the greatest threats to biodiversity, pushing species to shift their distribution ranges and making existing protected areas inadequate. Estimating species distribution and potential modifications under climate change are then necessary for adjusting conservation and management plans; this is especially true for endangered species. An example of this issue is the huemul (), an endemic endangered deer from the southern Andes Range, with less than 2,000 individuals.

Tailoring 2D and 3D molecular sieves structures for polyolefin composites: do all roads lead to remarkable performances?

Multiple synthetic strategies were performed in order to tether a zirconium-based catalyst to the 2D and 3D molecular sieves for olefin polymerizations. The anchoring of fluorene silane to the mesoporous MCM-41 was performed in order to obtain a stable catalyst for olefin polymerization (1@MCM-41). Using spectroscopic methods, this system was shown to have the metal center locked on a face down conformation with the surface.

Soft-Pillared@Magadiite: influence of the interlayer space and amine type on CO adsorption.

Layered silicates are versatile materials that can be grafted with different organosilanes for several applications. Despite this, there are few studies on the use of layered silicate-based materials in CO adsorption. In this regard, the present study describes the synthesis of organo-magadiite followed by simultaneous grafting with two organosilanes ((3-glycidyloxypropyl)trimethoxysilane (GPTS) and N-(3-trimethoxysilylpropyl)diethylenetriamine (TMSPETA)) to prepare an adsorbent labeled Soft-Pillared@Magadiite.

2D-to-disguised 3D materials with built-in acid sites: H-[Al]-RUB-18.

Al heteroions have been incorporated into the silicate layers of Na-RUB-18 in three different molar ratios Si/Al (22, 40 and 42) through a post-synthesis procedure under hydrothermal conditions. Systematic characterization (XRD, Si NMR, Al NMR and SEM) showed that these Na-[Al]-RUB-18 layered aluminosilicates are free from impurities, and the aluminum did not affect the crystallinity of the material, and also did not change its morphology. Al NMR showed that aluminum was incorporated in the tetrahedral position and the layered sample with molar ratio Si/Al = 22 has also displayed octahedral coordination.

Gel Electrolytes with Polyamidopyridine Dendron Modified Talc for Dye-Sensitized Solar Cells.

Organic-inorganic hybrid layered materials are proposed as additives in a quasi-solid gel electrolyte for dye-sensitized solar cells. Talcs could provide a low-cost and environmentally friendly, as well as abundant, option as gelators. Here, talcs were prepared by functionalizing an organotalc with three polyamidopyridine dendron generations, PAMPy-talc-Gn (n = 1, 2 and 3).

Toward a Delaminated Organotalc: The Use of Polyamidoamine Dendrons.

A sequence of generations of the polyamideamine dendron, PAMAM-talc-Gn (n = 1-7), was constructed on the surfaces of ethylenediaminepropyl-functionalized magnesium phyllosilicate lamellas by using a modified microwave-assisted synthesis. The successful functionalization of the inorganic layers by the organic dendrimer was confirmed by FTIR and (13)C NMR spectroscopies, elemental analyses, and thermogravimetric analysis (TGA). The solid materials presented an increase in their interlamellar space and disorganization of lamella packing with the growth of the dendrons.

Functionalized mesoporous solids based on magadiite and [Al]-magadiite.

Novel hybrid mesoporous and functionalized materials with controllable surface area and pore dimensions with functional basic sites (-NH2) were synthesized from magadiite and [Al]-magadiite as layered silicate precursors. The variable pore structure and properties of these materials were investigated in these solids by using different CTA(+)/Na(+) (CTA(+) = cetyltrimethylammonium cation) molar ratios in the pre-modification step with aminopropyltriethoxysilane (APTS) and tetraethoxysilane (TEOS). Characterizations were carried out by different techniques to probe the effects of the amounts of interlayer surfactant in the synthesis of the pillared and/or grafted materials.

Polyethylenimine-magadiite layered silicate sorbent for CO2 capture.

This paper describes the preparation of a Layered Silicate Sorbent (LSS) for CO2 capture using the layered silicate magadiite and organo-magadiite modified with polyethylenimine (PEI). The sorbents were characterized and revealed the presence of PEI as well as its interaction with CO2 at low temperatures. The thermal stability of sorbents was confirmed by thermogravimetry experiments, and the adsorption capacity was evaluated by CO2-TPD experiments.

Comparative adsorption of CO2 by mono-, di-, and triamino-organofunctionalized magnesium phyllosilicates.

Carbon dioxide adsorbents, constituted by organofunctionalized magnesium phyllosilicates, were produced using 3-aminopropyltriethoxysilane (AMPTS), N-[3-(trimethoxysilyl)propyl]-ethylenediamine (TMSPEDA), N-[3-(trimethoxysilyl)propyl]-diethylenetriamine (TMSPETA), and tetraethoxyorthosilane (TEOS) as silicon sources with N/Si ratios of 1, 0.75, 0.5, and 0.

Vanadium oxide intercalated with polyelectrolytes: novel layered hybrids with anion exchange properties.

Novel anion exchange hybrid materials were developed by the insertion of poly(diallymethylammonium chloride) (PDDACl) and poly(allylamine hydrochloride) (PAHCl) polyelectrolytes into V(2)O(5) interlayer spaces using hydrothermal treatment and were used to host an anionic cyanine dye. A systematic study of the hybrid material synthesis by direct in situ reaction of PDDACl and PAHCl polycations with V(2)O(5) powders showed that the interlayer space of V(2)O(5) expands from 0.44 nm to 1.

Physicochemical characterization and surface acid properties of mesoporous [Al]-SBA-15 obtained by direct synthesis.

In this work, [Al]-SBA-15 samples were prepared by three different direct synthesis methods and one postsynthesis procedure, aiming to study the influence of the preparation procedures on their structural, textural, and physicochemical features. To this aim, samples were investigated by combining different experimental techniques (XRD, N(2) physisorption, (27)Al-MAS NMR, and IR spectroscopy). All preparation methods led to the formation of aluminum-containing SBA-15 samples.

MCM-41 and Na-magadiite silicates internal voids probed by pyrene fluorescence spectroscopy.

Investigation of the properties of two different silicate materials, namely MCM-41, with one-dimensional, cylindrical pores (4.04 nm diameter), and Na-magadiite, with a bidimensional, layered structure (1.67 nm between layers) was carried out.

Aminopropyl-modified magnesium-phyllosilicates: layered solids with tailored interlayer access and reactivity.

Despite its wide application, the synthesis of aminopropyl-modified magnesium-phyllosilicates was known only in the case where every silicon atom bore an organic pending group. This paper shows the preparation of aminopropyl-modified talc where tailored amounts of silicon atoms are bound to an aminopropyl group. The decrease in the concentration of the organoamino group leaves a proportional concentration of interlayer SiOH groups that can be used to react with other silylation agents.

A combined high-resolution X-ray powder diffraction, computational, and XPS study of the local structure of extra-framework copper ions in over-exchanged Cu-MCM22 zeolite.

Local structure and site distribution of extra-framework copper ions in over-exchanged Cu-MCM22 zeolite were determined by a combination of high resolution X-ray powder diffraction and computational analysis. X-ray diffraction data suggested the presence of three Cu sites in six-membered rings and one site in a five-membered ring close to the interlamellar region, inside the MCM-22 supercage, whereas no Cu ions were found within the sinusoidal channels. First principle molecular orbital DFT calculations were employed to obtain, for the first time, an accurate structural description of the Cu(I) sites in the supercage, adding a structural and energetic interpretation to previous IR and EPR studies.

Temperature-induced transformations in CoAPO-34 molecular sieve: a combined in situ X-ray diffraction and FTIR study.

Thermally induced processes of CoAPO-34, an aluminophosphate molecular sieve with chabasite-type structure, synthesized in the presence of morpholine as a structure-directing agent and HF as a mineralizing agent, have been studied by in situ X-ray synchrotron powder diffraction augmented with Fourier transform (FT) IR analysis. A time-resolved experiment was performed using a translating imaging plate system. At room temperature, the structure refinement by full-profile Rietveld analysis showed P-1 symmetry and the presence of one Al site with sixfold coordination.

Micellization of CTAB in the presence of silicate anions and the exchange between bromide and silicate at the micelle surface: A step to understand the formation of mesoporous molecular sieves at extremely low surfactant and silicate concentrations.

The effect of silicate anions, from dilute aqueous tetramethylammonium silicate (TMASi) solutions (0-3.0 mmol L(-1) in silicon), on the formation of hexadecyltrimethylammonium bromide (CTAB) micelles was investigated by means of a series of simple conductivity experiments. These two compounds are used in the preparation of mesoporous silicate molecular sieves.

Physical chemistry of nanostructured molecular sieves by the study of phase diagrams: the case of the cetyltrimethylammonium bromide-tetramethylammonium silicate-water system.

A phase diagram for the system cetyltrimethylammonium bromide (CTAB)/tetramethylammonium silicate (TMASi)/water has been constructed in order to better understand the interactions between these precursors of the MCM-41 mesoporous molecular sieves. Three different CTAB concentration regions were analyzed: the dilute and semidilute regions, where simple surfactant species, such as monomers and spherical and nonspherical CTAB micelles, are found, and the concentrated region, involving liquid-crystalline phases. In the dilute and semidilute regions, the formation of a white nanostructured solid, having a hexagonal array similar to that found in MCM-41 materials, was observed.