Synthesis, characterization and DFT studies of diethyl 4-hydroxy-6-nitro-4H-chromene-2,3-dicarboxylate

• Published in: Journal of molecular structure 2016-02, Vol.1105, p.118-127
• Main Authors: Dinparast, Leila, Valizadeh, Hassan, Vessally, Esmail, Bahadori, Mir Babak
• Format: Article
• Language: English
• Subjects: Chromene; DFT; MEP; Mulliken charges; NBO; Vibrational mode
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2015.10.044

In the present study, diethyl 4-hydroxy-6-nitro-4H-chromene-2,3-dicarboxylate (DHNC) was synthesized and characterized using FT-IR, 1H and 13CNMR spectroscopy, mass spectrometry and UV–Vis (200–700 nm, in DMSO) spectrum. The structure of the title molecule was optimized at the B3LYP and PBE1PBE levels of theory using 6–311++G(d,p) basis set. The fundamental vibrational modes and chemical shifts of 1H and 13C of the present molecule were calculated using the B3LYP/6–311++G(d,p) and PBE1PBE/6–311++G(d,p) methods. UV–Vis spectrum of the title molecule was also calculated in DMSO and gas phase. The high stability and charge delocalization of DHNC arising from intramolecular hyperconjugative interaction confirmed with the NBO analysis at two DFT methods. Theoretical studies of the molecular orbitals such as HOMO-LUMO energy gap, mapped molecular electrostatic potential (MEP) surfaces and the Mulliken and NBO charges were also performed with the same levels of theory. In this work, the computed results and experimental observations support well each other. •One-pot and solvent-free synthesis of diethyl 4-hydroxy-6-nitro-4H-chromene-2,3-dicarboxylate (DHNC).•Structure elucidation of DHNC using UV–vis, FT-IR, 1H and 13CNMR and mass spectra.•Quantum chemical calculations using B3LYP/6–311++G(d,p) and PBE1PBE/6–311++G(d,p) methods.•Good agreement between the theoretical results and experimental observations.