Layered double alkoxides a novel group of layered double hydroxides without water content

Abstract

It has been generally accepted for long that water molecules are integral parts of layered double hydroxides (LDHs). It is even thought that in the absence of water molecules, there is no LDH structure. It is shown in this contribution that via the solvolysis of Mg-or Ca-alkoxides and Al-alkoxide with methanol or propanol and co-precipitated in methanolic methoxide, waterfree LDH-like structures could be constructed. These novel LDH-like materials proved to be more active and selective catalysts in a Knoevenagel condensation than the corresponding 'classical' LDHs. IMPACT STATEMENT Synthesis, thought to be not possible to prepare, characterization and a catalytic application of water-free LDHs are described. Water molecules are replaced by small alcohol molecules in the interlayer space.

Distinguishing Anionic Species That Are Intercalated in Layered Double Hydroxides from Those Bound to Their Surface: A Comparative IR Study

“…One of the most often used anionexchange families is the layered double hydroxides (LDHs) in which the positive charges of the double (M 2+ and M 3+ ) metal hydroxide layers were compensated by interlamellar solvated anions. 20,21 These interlayer anions can be further exchanged with more or less difficulties by different type of anions such as amino carboxylates, 22,23 polyoxometallates, 24 Schiff-base complexes, 25 polymeric anions, 26 DNA, 27 etc. In parallel to this process, surface adsorption of the guest molecules could also occur.…”

“…To modify 2D ion-intercalated compounds, many different intercalation (wet-) chemical methods have been reported; based on these results, a large number of mixed inorganic or organo-layered composite materials were built up. − Through corresponding ion-exchange properties, these compounds can be divided into two groups, i.e., cation- and anion-exchanging materials. One of the most often used anion-exchange families is the layered double hydroxides (LDHs) in which the positive charges of the double (M 2+ and M 3+ ) metal hydroxide layers were compensated by interlamellar solvated anions. , These interlayer anions can be further exchanged with more or less difficulties by different type of anions such as amino carboxylates, , polyoxometallates, Schiff-base complexes, polymeric anions, DNA, etc. In parallel to this process, surface adsorption of the guest molecules could also occur …”

Three-dimensional mesoporous ultrathin monometallic cobalt layered double hydroxides nanomaterials as efficient NO2 gas sensor at room temperature

“…The characteristic peak at 1058 cm −1 was related to the tensile vibration mode of C–O, which can be considered as the characteristic absorption caused by the insertion of methanol molecules during the preparation process. 50,51 Furthermore, the peak nearby at 1629 cm −1 revealed a vibration band of the bending mode of water molecules, confirming the presence of interlayer molecular water. 52 The sharp, strong peak at 1384 cm −1 was attributed to the symmetric scaling vibrational band of the nitrate ions, demonstrating that the synthesized samples were LDHs of the NO 3 − type, 34 which was consistent with the XRD patterns.…”

Suppressing Electrolyte Decomposition at Cathode/Electrolyte Interface by Mg-Fe Binary Oxide Coating towards Room-Temperature Magnesium Rechargeable Battery Operation

“…S3), and peaks attributable to the Mg-layered product were observed, which were presumed to be Mg-Mn-layered double hydroxide generated from the reaction between partially dissolved Mn 3+ (formed during the reflux process) and Mg ethoxide. 32 After the Mg-Fe bilayer coating and the following calcination, the peaks attributable to the layered product disappeared (Fig. S3 and Fig.…”