Inclusion Complexes of 3,4-Ethylenedioxythiophene with Per-Modified β- and γ-Cyclodextrins

Abstract

Herein, we report the synthesis of inclusion complexes (ICs) based on 3,4-ethylenedioxythiophene (EDOT) with permethylated β-cyclodextrins (TMe-βCD) and permethylated γ-cyclodextrins (TMe-γCD) host molecules. To prove the synthesis of such ICs, molecular docking simulation, UV-vis titrations in water, 1H-NMR, and H-H ROESY, as well as matrix-assisted laser desorption ionization mass spectroscopy (MALDI TOF MS) and thermogravimetric analysis (TGA) were carried out on each of the EDOT∙TMe-βCD and EDOT∙TMe-γCD samples. The results of computational investigations reveal the occurrence of hydrophobic interactions, which contribute to the insertion of the EDOT guest inside the macrocyclic cavities and a better binding of the neutral EDOT to TMe-βCD. The H-H ROESY spectra show correlation peaks between H-3 and H-5 of hosts and the protons of the guest EDOT, suggesting that the EDOT molecule is included inside the cavities. The MALDI TOF MS analysis of the EDOT∙TMe-βCD solutions clearly reveals the presence of MS peaks corresponding to sodium adducts of the species associated with the complex formation. The IC preparation shows remarkable improvements in the physical properties of EDOT, rendering it a plausible alternative to increasing its aqueous solubility and thermal stability.

Novel Insight into the Photophysical Properties and 2D Supramolecular Organization of Poly(3,4-ethylenedioxythiophene)/Permodified Cyclodextrins Polyrotaxanes at the Air–Water Interface

“…The 1 H-NMR and 13 C-NMR data confirmed the chemical structure of TMe-βCD and TMe-γCD host molecules [ 27 ]. Further, TMe-βCD and TMe-γCD macrocycles solubilized in a minimal amount of water were subjected to encapsulating the EDOT into their cavities based on intermolecular interactions, thus leading to EDOT∙TMe-βCD and EDOT∙TMe-γCD [ 28 ]. The ability of TMe-βCD or TMe-γCD host molecules to bind the neutral guest EDOT was demonstrated by UV–vis titrations in water.…”

“…Furthermore, the binding ability of the EDOT starting monomer to the hosts TMe-βCD and TMe-γCD was verified by molecular docking simulation. The results of computational data reveal the occurrence of hydrophobic interactions, which contribute to the insertion of the EDOT guest inside the macrocyclic cavities and a better binding of the EDOT to TMe-βCD [ 28 ]. The 1 H-NMR spectra of the EDOT∙TMe-βCD and EDOT∙TMe-γCD denoted chemical shift displacements for all the protons of EDOT and macrocyclic molecules.…”

“…The 1 H-NMR spectra of the EDOT∙TMe-βCD and EDOT∙TMe-γCD denoted chemical shift displacements for all the protons of EDOT and macrocyclic molecules. According to the 1 H-NMR analysis, the EDOT was included in the central cavities of TMe-βCD and TMe-γCD owing to the largest chemical shift variations that were identified for the H-3 and H-5 protons located inside the macrocyclic cavity [ 28 ]. In order to achieve a more detailed structural assessment of the EDOT∙TMe-βCD and EDOT∙TMe-γCD compounds, two-dimensional H-H ROESY analyses were further performed.…”

“…The chemical structures of the resulting PEDOT∙TMe-βCD and PEDOT∙TMe-γCD compounds were validated by using FT-IR ( Figure S3 ) and NMR spectroscopy. The FT-IR spectra show all of the characteristic bands of PEDOT at 1323, 1157, 980, 921, 817, and 673 cm −1 [ 31 ], and additional bands located at 1073, 1060, 571, 519, and 434 cm −1 that evidence the presence of the TMe-βCD or TMe-γCD [ 28 , 32 ]. The presence of characteristic vibration at 3043 cm −1 (C-H stretching mode), 1589 cm −1 (C=C stretching), 1157 cm −1 (C=C bending), 832 and 702 cm −1 (C-H bending) also evidenced that the Py stopper was attached to the PEDOT ends [ 33 ].…”

“…EDOT∙TMe-βCD and EDOT∙TMe-γCD starting monomers were prepared according to our recently reported procedure [ 28 ].…”