Search results for "Hydroxides"

Hybrid Materials Based on Magnetic Layered Double Hydroxides: A Molecular Perspective

2015

Design of functional hybrids lies at the very core of synthetic chemistry as it has enabled the development of an unlimited number of solids displaying unprecedented or even improved properties built upon the association at the molecular level of quite disparate components by chemical design. Multifunctional hybrids are a particularly appealing case among hybrid organic/inorganic materials. Here, chemical knowledge is used to deploy molecular components bearing different functionalities within a single solid so that these properties can coexist or event interact leading to unprecedented phenomena. From a molecular perspective, this can be done either by controlled assembly of organic/inorga…

Interplay between Chemical Composition and Cation Ordering in the Magnetism of Ni/Fe Layered Double Hydroxides

2013

We report the synthesis of a family of ferrimagnetic NiFe layered double hydroxides (LDHs) with a variable Ni(2+)/Fe(3+) in-plane composition of [Ni(1-x)Fe(x)(OH)2](CO3)(x/2)·yH2O (x = 0.20, 0.25, and 0.33) by following a modified homogeneous precipitation. These layered magnets display high crystallinity, homogeneous hexagonal morphologies, and micrometric size that enable their quantitative exfoliation into single layers by sonomechanical treatment of the solids in polar solvents. This was confirmed by dynamic light scattering, UV-vis spectroscopy, high-resolution transmission electron miscroscopy, and atomic force microscopy methodologies to study the resulting steady suspensions. Our ma…

Room Temperature Magnetism in Layered Double Hydroxides due to Magnetic Nanoparticles

2013

Some recent reports claiming room temperature spontaneous magnetization in layered double hydroxides (LDHs) have been published; however, the reported materials cause serious concern as to whether this cooperative magnetic behavior comes from extrinsic sources, such as spinel iron oxide nanoparticles. The syntheses of crystalline Fe(3+)-based LDHs with and without impurities have been developed, highlighting the care that must be taken during the synthetic process in order to avoid misidentification of magnetic LDHs.

Deciphering the Role of Dipolar Interactions in Magnetic Layered Double Hydroxides

2018

Layered double hydroxides (LDHs) exhibit unparalleled anion exchange properties and the ability to be exfoliated into 2D nanosheets, which can be used as a building block to fabricate a wide variety of hybrid functional nanostructured materials. Still, if one wants to use LDHs as a magnetic building blocks in the design of complex architectures, the role played by the dipolar magnetic interactions in these layered materials needs to be understood. In this work, we synthesized and characterized a five-membered CoAl-LDH series with basal spacing ranging from 7.5 to 34 Å. A detailed experimental characterization allows us to conclude that the main factor governing the dipolar interactions betw…

Cover Feature: Fundamental Insights into the Covalent Silane Functionalization of NiFe Layered Double Hydroxides (Chem. Eur. J. 29/2020)

2020

Acetazolamide-M(II) [M(II) = Co(II), Ni(II), Cu(II)] complexes with ethylamine, diethylamine, triethylamine, and potassium hidroxide

1991

Abstract Complexes of Co(II), Ni(II), and Cu(II) with dideprotonated Acm are synthesized and characterized. Acm acts as bidentate ligand through the N-sulfonamido atom and the N-thiadiazole atom except for K6CoAcm4·6H2O in which Acm behaves as monodentate through the N-sulfonamido atom.

Layered Double Hydroxides

2020

The impact of layered double hydroxides (LDHs) within the multidisciplinary fields of materials sciences, physics, chemistry, and biology is rapidly growing, given their easiness of synthesis, flexibility in composition, tunable biocompatibility and morphology. LDHs constitute a versatile platform for the realization of new classes of functional systems, showing unique enhanced surface effects and unprecedented properties for application in very different fields, namely, surface chemistry and catalysis, storage and triggered release of functional anions, flame retardants, drug delivery and nanomedicine, remediation, energy storage and conversion. These systems can be synthesized as self-ass…

Boron and lithium behaviour in river waters under semiarid climatic conditions

2022

Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very simil…

Spatial analysis of the relationship between mortality from cardiovascular and cerebrovascular disease and drinking water hardness

2004

Journal Article; Research Support, Non-U.S. Gov't; Reproduced with permission from Environmental Health Perspectives. Previously published scientific papers have reported a negative correlation between drinking water hardness and cardiovascular mortality. Some ecologic and case-control studies suggest the protective effect of calcium and magnesium concentration in drinking water. In this article we present an analysis of this protective relationship in 538 municipalities of Comunidad Valenciana (Spain) from 1991-1998. We used the Spanish version of the Rapid Inquiry Facility (RIF) developed under the European Environment and Health Information System (EUROHEIS) research project. The strateg…

Zn,Al hydrotalcites calcined at different temperatures: Preparation, characterization and photocatalytic activity in gas–solid regime

2011

Abstract Layered double hydroxides (LDH) containing zinc and aluminium within the brucite-like layers and carbonate as the interlayer anion have been used as precursors for the preparation of mixed metal oxides by calcination. Zinc oxide and the ZnAl 2 O 4 spinel were formed with different degree of crystallinity depending of two parameters, i.e., the Zn 2+ /Al 3+ molar ratio and the calcination temperature (500–800 °C) of the LDH precursor. A pure spinel phase was obtained to remove ZnO upon a basic post-treatment in NaOH solution of the samples calcined at 800 °C. All the samples were tested for the photodegradation of 2-propanol in gas–solid regime. All the samples resulted active as het…