Supramolecular Organogels Based on N-Benzyl, N′-Acylbispidinols

Nanomaterials

JudithA. K. Howard¹  VyacheslavN. Nuriev²  SergeyZ. Vatsadze²  AlexanderI. Dalinger²  AlexanderE. Baranchikov²  VeraS. Semashko²  AlexeyV. Medved’ko²  AlexanderA. Ezhov³  AndreyA. Shiryaev⁴  VladimirK. Ivanov⁵  AndreiV. Churakov⁵  AndreiV. Filatov⁶ 

[1] Department of Chemistry, University of Durham, Durham DH1 3LE, UK;Faculty of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia;Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia;Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, 119991 Moscow, Russia;Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia;

关键词: organic nanomaterials;    bispidines;    supramolecular gels;    SEM;    TEM;    AFM study;    X-ray diffraction;    FTIR spectroscopy;    ATR spectroscopy;    SAXS;   

DOI  :  10.3390/nano9010089

来源: DOAJ

【 摘 要 】

The acylation of unsymmetrical N-benzylbispidinols in aromatic solvents without an external base led to the formation of supramolecular gels, which possess different thicknesses and degrees of stability depending on the substituents in para-positions of the benzylic group as well as on the nature of the acylating agent and of the solvent used. Structural features of the native gels as well as of their dried forms were studied by complementary techniques including Fourier-transform infrared (FTIR) and attenuated total reflection (ATR) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and small-angle X-ray scattering and diffraction (SAXS). Structures of the key crystalline compounds were established by X-ray diffraction. An analysis of the obtained data allowed speculation on the crucial structural and condition factors that governed the gel formation. The most important factors were as follows: (i) absence of base, either external or internal; (ii) presence of HCl; (iii) presence of carbonyl and hydroxyl groups to allow hydrogen bonding; and (iv) presence of two (hetero)aromatic rings at both sides of the molecule. The hydrogen bonding involving amide carbonyl, hydroxyl at position 9, and, very probably, ammonium N-H+ and Cl− anion appears to be responsible for the formation of infinite molecular chains required for the first step of gel formation. Subsequent lateral cooperation of molecular chains into fibers occurred, presumably, due to the aromatic π−π-stacking interactions. Supercritical carbon dioxide drying of the organogels gave rise to aerogels with morphologies different from that of air-dried samples.

【 授权许可】

Unknown