Molecular Recognition via Hydrogen Bonding in Supramolecular Complexes: A Fourier Transform Infrared Spectroscopy Study

Abstract

We assess the assembly of supramolecular complexes by hydrogen bonding between azocompounds and a diacylaminopyridine monomer by temperature-dependent Fourier transform infrared spectroscopy (FT-IR) and density functional theory (DFT) calculations. The electronic delocalisation in the supramolecular rings formed by multiple hydrogen bonds stabilises the complexes, which coexist with dimeric species in temperature-dependent equilibria. We show how the application of readily available molecular modelling and spectroscopic techniques can predict the stability of new supramolecular entities coexisting in equilibria, ultimately assessing the success of molecular recognition.

Twist-Bend Nematogenic Supramolecular Dimers and Trimers Formed by Hydrogen Bonding

“…The shape of the carbonyl stretching region indicates that the carbonyl groups are present in a range of chemical environments, and this band shape strongly resembles that reported previously for CB6OBA/pyridyl mixtures [42]. The carbonyl stretching region (1650−1740 cm −1 ) is complex, see Figure 8b, and contains a broad peak comprising a number of vibrations associated with the various acidic species present in dynamic equilibrium in the mixture: namely, free or monomeric benzoic acids (C=Omon., ≥ 1730 cm −1 ), asymmetric acid dimers (C=Oasym., 1730−1680 cm −1 ), symmetric acid dimers (C=Osym, 1680 cm −1 ), and catemeric acid aggregates (C=Ocat., 1660 cm −1 ), see Figure 9 [46]. This region also contains the carbonyl stretching band associated with the heterocomplexes formed by the unlike acid and stilbazole-based fragments [47].…”

Induced Phases of New H-bonded Supramolecular Liquid Crystal Complexes; Mesomorphic and Geometrical Estimation

“…Supramolecular H-bonded liquid crystals (SMHBLCs) combine of supramolecular chemistry with mesogenic behavior principles. The induced mesophase or mesophase stabilities in such systems are most often attributed to the enhancement of the molecular anisotropy of the resulting complexes with respect to that of the individual components [23][24][25][26][27][28]. The mesomorphic behavior of a wide variety of SMHBLC dimers have been reported by varying the spacer length and the molecular structures of the individual components [6].…”

“…The mesomorphic behavior of a wide variety of SMHBLC dimers have been reported by varying the spacer length and the molecular structures of the individual components [6]. There is a different approach in which can control the molecular shape using H-bonding [23][24][25][26][27][28]. Most of the SMHLCs studied are based on the rod-like intermolecular H-bonding [10,[12][13][14][29][30][31] and there is a lot of interest towards the formation of angular supramolecular hydrogen-bonded liquid crystals [9].…”

New chair shaped supramolecular complexes-based aryl nicotinate derivative; mesomorphic properties and DFT molecular geometry

“…SMHBLCs are mostly based on pyridyl and carboxylic derivatives, as proton acceptor and proton donor moieties, respectively. [10][11][12][13] Schiff base compounds are widely used in many elds, such as catalytic reactions and photochemistry. 14,15 Many Schiff bases with a low molar mass have been synthesized and investigated extensively for applications with liquid crystals.…”