Synthesis and characterization of Mg–Al-layered double hydroxides intercalated with cubane-1,4-dicarboxylate anions

Abstract

In the present work, Mg2Al-layered double hydroxide (LDH) intercalated with cubane-1,4-dicarboxylate anions was prepared from the reaction of solutions of Mg(ii) and Al(iii) nitrate salts with an alkaline solution of cubane-1,4-dicarboxylic acid by using the coprecipitation method. The successful preparation of a nanohybrid of cubane-1,4-dicarboxylate(cubane-dc) anions with LDH was confirmed by powder X-ray diffraction, FTIR spectroscopy and thermal gravimetric analysis (TGA). The increase in the basal spacing of LDHs from 8.67 Å to 13.40 Å shows that cubane-dc anions were successfully incorporated into the interlayer space. Thermogravimetric analyses confirm that the thermal stability of the intercalated cubane-dc anions is greater than that of the pure form before intercalation because of host-guest interactions involving hydrogen bonds. The interlayer structure, hydrogen bonding, and subsequent distension of LDH compounds containing cubane-dc anions were shown by molecular simulation. The RDF (radial distribution function), mean square displacement (MSD), and self-diffusion coefficient were calculated using the trajectory files on the basis of molecular dynamics (MD) simulations, and the results indicated that the cubane-dc anions were more stable when intercalated into the LDH layers. A good agreement was obtained between calculated and measured X-ray diffraction patterns and between experimental and calculated basal spacings.

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

“…DOS calculations computed with the DFT method and the molecular orbitalm odels showedaredshift in the spectrumo ft he large intercalated cubane-dc anionsw ith a subsequentl ower band energy gap than that of Zn-Al-NO 3 -LDH, which is amuch smaller anion. [334] The singly metal-metal-bonded complex [Rh 2 (cis-DAniF) 2 -(CH 3 CN eq ) 4 (CH 3 CN ax ) 2 ](BF 4 ) 2 (DAniF = N,N'-di-p-anisylformamidinate) was assembled with (Et 4 N + ) 2 (Carb 2À ), in which Carb 2À is the dicarboxylate anion of BCP and cubane 273 and 274,r espectively,a mongsto ther groups to form square complexes (Figure 51 iii). In crystal form these complexes stack forming infinite tunnels which can be closed to allow for the encapsulation of solvent molecules.…”

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

“…In this context, the combination of spectroscopic and computational techniques is fundamental to evaluate the host-guest interactions and to calculate the geometric and electronic structures of the LDH intercalated with guest species. [183][184][185] The structure of LDHs, although simpler than that of other layered materials such as natural cationic clays, has been largely studied in relation to: (i) charge distribution within the brucitic layer and their local order/disorder at short or long range; (ii) influence of the cation size for maintaining a hydrotalcite-like structure; (iii) order/disorder degree of the anions into the interlayer region and interactions with the brucitic layer; (iv) influence of the interlayer water content on the reactivity; (v) layer stacking and (vi) microstructural defects due to stacking faults and turbostratic disorder. A large number of experimental methods with computational techniques have been very often used to clarify the above-mentioned points.…”

Preparation of cubane-1,4-dicarboxylate–Zn–Al layered double hydroxide nanohybrid: comparison of structural and optical properties between experimental and calculated results

“…26 So, a solution containing the cubane-1,4-dicarboxylic acid (0.172 g, 0.001 mol) dissolved in NaOH (20 mL, 0.1 M) was slowly added to an aqueous mixed solution (20 mL) of Zn(NO 3 ) 2 $6H 2 O (0.5949 g, 0.002 mol) and Al(NO 3 ) 3 $9H 2 O (0.375 g, 0.001 mol) with vigorous stirring in the nitrogen atmosphere. 26 So, a solution containing the cubane-1,4-dicarboxylic acid (0.172 g, 0.001 mol) dissolved in NaOH (20 mL, 0.1 M) was slowly added to an aqueous mixed solution (20 mL) of Zn(NO 3 ) 2 $6H 2 O (0.5949 g, 0.002 mol) and Al(NO 3 ) 3 $9H 2 O (0.375 g, 0.001 mol) with vigorous stirring in the nitrogen atmosphere.…”

“…26 In the present work the preparation of the Zn-Al hydrotalcite intercalated with the cubane-1,4-dicarboxylate anions (hereaer abbreviated as cubane-dc) are reported. The aforementioned distribution resulted from non-bonding and the host-guest interactions based on van der Waals and electrostatic forces in cubane-dc-Mg-Al-LDH.…”

“…26 In viewpoint of rst classical geometry optimization, cubane-1,4-dicarboxylate anion has a symmetrical structure and unique position for bonding and nonbonding interaction with layer of LDHs. Cubane derivatives are widely used as novel organic anions for high-energy explosives, 25 oligomeric compound and pharmaceutical materials.…”