Controllable Nanocage Structure Derived from Cyclodextrin-Intercalated Layered Double Hydroxides and Its Inclusion Properties for Dodecylbenzene

Abstract

A novel nanocage structure derived from carboxymethyl--cyclodextrins (CMCDs) intercalated in layered double hydroxides (LDHs), whose gates can be controlled by the process of swelling/drying the CMCD-LDH, has been prepared. Furthermore, the extent of opening of this nanocage structure can be controlled by swelling in different solvents. Dodecylbenzene (DDB) as the guest molecule has been incorporated into the nanocage structure through two different routes: intercalation of CMCD in the LDH followed by inclusion of DDB (intercalation-inclusion method) and inclusion of DDB in CMCD followed by intercalation of the host-guest complex into the LDH (inclusion-intercalation method). For the convenience of using this nanocage as an absorbent and storage vessel for neutral guest, films of the resulting composite materials (CMCD-LDH) were fabricated by the method of solvent evaporation on glass substrates. The structures, chemical compositions, morphologies, and physicochemical properties of the materials were fully studied. Moreover, the effects of the combined confinement of both the LDH layers and the cyclodextrin cavity on the encaged guest were investigated. Compared with the confinement effect produced by cyclodextrin only, this double-confinement imposes stronger restrictions on the mobility of the guest molecule, which leads to a blue shift of the fluorescence spectrum and increases the decay time of the guest. Therefore, this structured nanocage might have potential applications as adsorbents, synergistic agents, and storage vessels for neutral molecules.

Nanocage Structure Derived from Sulfonated β-Cyclodextrin Intercalated Layered Double Hydroxides and Selective Adsorption for Phenol Compounds

“…Change or not for the d basal after the inclusion of guests may depend on the characteristics of the entered guests, especially the hydrophilic/hydrophobic property or space hindrance. Wei and coworkers 18 proposed the CD intercalated LDHs can be seen as nanocavities with controllable nanocage structure, and they presented swelling/contraction properties in solvents. When the CD nanocage intercalates into the interlayer of LDH, both openings of the CD are blocked by LDH sheets, forming a lockable nanocage.…”

Dynamics analysis of anion exchange in layered double hydroxides

“…The precursor NO 3 -LDHs was prepared by a coprecipitation method similar to that reported previously (Liu et al 2008;Liu and Meng 2013). A solution of Zn(NO 3 ) 2 (0.12 mol) and Al(NO 3 ) 3 (0.06 mol) in deionized water (200 mL) was added dropwise over 2 h to a solution of NaOH (0.31 mol) and NaNO 3 (0.21 mol) in water (100 mL).…”

Chiral Recognition of Lysine by Cyclodextrin Intercalated Layered Double Hydroxides

“…In recent years, the immobilization of cyclodextrins with layered double hydroxides has attracted much attention. Modified cyclodextrins have been used as a "guest" molecule incorporating into layered hosts [12][13][14] . In our previous work, we have shown that when the internal surfaces of the layered double hydroxides are functionalized by anchoring anionic cyclodextrin cavities, neutral racemic guest molecule can be enantioselectively included within it 15,16 .…”

“…Synthesis of CMCD-LDHs: The precursor Zn0.67Al0.33(OH)2(NO3)0.33•yH2O (NO3-LDHs) was synthesized by a procedure similar to that of described prebviously 14,16 . Under N2 atmosphere through the conventional route, a solution of Zn(NO3)2•6H2O (1.2 × 10 -1 mol) and Al(NO3)3•9H2O (6.0 × 10 -2 mol) in deionized water (2.0 × 10 -4 m 3 ) was added dropwise over 2 h to a solution of NaOH (3.1 × 10 -1 mol) and NaNO3 (2.1 × 10 -1 mol) in water (1.0 × 10 -4 m 3 ).…”