Intercalation of amino acid containing chiral dicarboxylic acid between Mg–Al layered double hydroxide

Abstract

Layered double hydroxide (LDH) is a class of ionic lamellar solids with positively charged layers with two types of metallic cations and exchangeable hydrated gallery anions. The intercalation of organic anions, namely N,N 0 -(pyromellitoyl)-bis-L-a-amino acids diacid, into MgAl LDHs was studied for the first time. Chiral diacid monomers were synthesized in high yield from the reaction between pyromellitic dianhydride and different natural amino acids (L-isoleucine, S-valine, L-leucine, and L-phenylalanine) in refluxed acetic acid. The anion exchange appeared to be the most effective method; all examined organic anions were intercalated successfully by this way in Mg-Al host structures. The structures of supramolecular chiral materials were characterized using Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy techniques. Thermogravimetry analysis results showed that there were five mass loss steps during the thermal decomposition of the hybrid materials. These optically active pillars create a chiral environment and they could be used in chiral field.

Using Mg‐Al‐layered double hydroxide intercalated with chiral dicarboxylic acid for the reinforcement of isoleucine amino acid containing poly(amide‐imide)

“…The band around 447 cm −1 results from the lattice vibration of the hydroxide sheet and the broad band in the range of 3,200–3,700 cm −1 mainly from O–H groups of the hydroxide layers are observed. A broad band or shoulder is observed in all modified samples in the range 1,600–1,640 cm −1 , which may indicate the presence of H 2 O molecules as bending vibration appears in this region . The absorption bands at 2,930–3,100 cm −1 correspond to the ν asym and ν sym (C‐H) modes of CH 2 group in the chiral dicarboxylate molecules.…”

“…Figure shows the FTIR spectra of MgAl‐LDH‐ , modified LDH and l‐ isoleucine containing diacid. For neat LDH, the broad band in the range 3,200–3,700 cm −1 is because of the O–H stretching vibration of the metal hydroxide layer and interlayer water molecules . The band characteristic to metal‐oxygen bond stretching appears below 700 cm −1 .…”

Influence of imide functionalized organo‐modified Mg‐Al layered double hydroxide on the thermal and mechanical properties of new aliphatic‐aromatic poly (amide‐imide)

“…The XRD patterns of DLDH, PAI, PAIDN 2 and PAIAN 2 are shown in Figure . The presence of the main reflections in the lower angles in the XRD pattern of DLDH compared to the neat Mg‐Al LDH indicated that dicarboxylic anion 3 as the organic modifier are existed in the LDH interlayers. The XRD pattern of DLDH exhibited some main reflections at 4.62°, 8.55°, 10.24° and 21.99° ° of 2Ө.…”

A facile and simple synthetic strategy for the preparation of modified NiAl-layered double hydroxide as nanofiller for L-phenylalanine containing poly(amide-imide)s based nanocomposites

“…200°C corresponds to removal of weakly adsorbed water and water intercalated in the interlayer galleries of ZnAl-LDH. [43,44] The second weight loss (230-680°C) involves dehydroxylation of the brucite-like layers and loss of volatile species arising from decomposition of the interlayer carbonate anions. For diacid modified NiAl-LDH, the larger weight loss step within 400-600°C confirmed the presence of organic diacid in the interlayer of the LDH (Figure 7).…”