R. Golla, P. Raghavendra Kumar, P. A. Suchethan
Feb 1, 2020
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Influential Citations
5
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Journal
Journal of Molecular Structure
Abstract
Abstract Four new 4′-dimethoxyphenyl-(2,6-di-2-pyrazinyl) pyridines (1–4) were synthesised by a facile one-pot method using 2-acetylpyrazine and n,n’-dimethoxybanzaldehydes. All compounds (1–4) were characterised by 1H and 13C{1H} NMR, and FT-IR spectroscopy. The molecular structure of compounds 1, 2, and 3 was also confirmed by single crystal X-ray diffraction. There exists CH ⋯ N, CH ⋯ O and C ⋯ C aromatic stacking type of intermolecular secondary interactions which resulted into supramolecular structures in compounds 1–3. The Hirshfeld surface analysis was carried out for the confirmation of intermolecular secondary interactions.The dihedral angles between substituted dimethoxyphenyl ring (B) and central pyridine (A) and pyrazine rings (C and D) are in the range of 33–45°. The photophysical properties were studied by UV–Visible and fluorescence spectroscopy and electrochemical properties by cyclic voltammetry. In the UV–Visible spectra, the compounds, 1–4 showed two strong bands at λmax, 236–238 and 284–293 nm attributed to the intramolecular charge transfer (π–π*) transitions. When these compounds were excited at 350 nm observed emission bands at λem, 463, 511, 462, and 407 nm respectively. The compounds, 1–3 were showed an oxidation peak, (Eox, 1.18, 1.57 and 1.25 V) but compound 4 showed two oxidation peaks (Eox, 1.20 and 1.84 V). Astonishingly, only compound, 3 have shown a reduction peak at (Ered, 1.33 V) but there was no reduction peak in 1, 2 and 4. This shows that the compound, 3 undergo reversible redox reaction.