Supramolecular Cocrystals : Synthesis, Structural Characterizations And Theoretical Studies

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Date
2017-06
Authors
Che Khalib, Nuridayanti
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Publisher
Universiti Sains Malaysia
Abstract
In this research work, nineteen novel cocrystals of various carboxylic acids and bases have been investigated using spectroscopic methods such as powder and single crystal X-ray Crystallography, Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR). The theoretical calculations of the cocrystals were performed using Density Functional Theory (DFT) method and Hirshfeld Surfaces analysis. Generally, the DFT and experimental results are comparable to each other except for the conformational difference around the carboxyl groups. Spectroscopic properties of the cocrystals were examined by FT-IR and NMR. Apart from the pKa values prediction, single crystal and powder X-ray diffractions show that all the samples are cocrystals. The molecular structures and the existence of intermolecular interactions have been confirmed by single crystal X-ray diffraction and the contribution of the interactions is shown by quantitative analysis of the Hirshfeld Surfaces. The formation of 2 (8) 2 R supramolecular heterosynthons motifs between the carboxylic acid and the aminopyridine, aminopyrimidine and aminotriazine moieties can be found in all the cocrystal structures forming the basis of the supramolecular structures. The arrangement of the heterosynthons in the crystal structure of some of the cocrystals generates a DADA array of cyclic heterotetrameric synthon and linear heterotetrameric synthon. These synthons are interconnected within the crystal structure of the cocrystals through various intermolecular interactions forming chains, 2-dimensional planes and 3-dimensional network of crystal structures.
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Keywords
Supramolecular cocrystals synthesis, structural , characterizations and theoretical studies
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