FT-IR, FT-Raman, NMR and UV-Vis spectra and DFT calculations of 5-bromo-2-ethoxyphenylboronic acid (monomer and dimer structures)
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2015
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Abstract
In this study, the Fourier Transform Infrared (FT-IR) and Fourier Transform Raman (FT-Raman) spectra of 5-bromo-2-ethoxyphenylboronic acid (5Br2EPBA) are recorded in the solid phase in the region 4000-400 cm-1 and 3500-10 cm-1, respectively. The 1H, 13C and DEPT nuclear magnetic resonance (NMR) spectra are recorded in DMSO solution. The UV-Vis absorption spectrum of 5Br2EPBA is saved in the range of 200-400 nm in ethanol and water. The following theoretical calculations for monomeric and dimeric structures are supported by experimental results. The molecular geometry and vibrational frequencies in the ground state are calculated by using DFT methods with 6-31G(d,p) and 6-311G(d,p) basis sets. There are four conformers for the present molecule. The computational results diagnose the most stable conformer of 5Br2EPBA as Trans-Cis (TC) form. The complete assignments are performed on the basis of the total energy distribution (TED) of vibrational modes, calculated with scaled quantum mechanics (SQM) method in parallel quantum solutions (PQS) program. The 1H and 13C NMR chemical shifts of 5Br2EPBA molecule are calculated by using the Gauge Invariant Atomic Orbital (GIAO) method in DMSO and gas phase for monomer and dimer structures of the most stable conformer. Moreover, electronic properties, such as the HOMO and LUMO energies (by TD-DFT and CIS methods) and molecular electrostatic potential surface (MEPs) are investigated. Stability of the molecule arising from hyper-conjugative interactions, charge delocalization is analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) properties and thermodynamic features are presented. All calculated results are compared with the experimental data of the title molecule. The correlation of theoretical and experimental results provides a detailed description of the structural and physicochemical properties of the title molecule. © 2014 Elsevier B.V. All rights reserved.
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Boronic Acids , Cross-Linking Reagents , Dimerization , Magnetic Resonance Spectroscopy , Models, Molecular , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , Absorption spectroscopy , Chemical bonds , Electronic properties , Ground state , Molecular vibrations , Molecules , Monomers , Nuclear magnetic resonance , Quantum chemistry , Quantum theory , Ultraviolet spectroscopy , Water absorption , 5-bromo-2-ethoxyphenylboronic acid , boronic acid derivative , cross linking reagent , Fourier transform infrared , FTIR and FT-Raman spectra , Molecular electrostatic potentials , Natural bond orbital analysis , NBO and NLO , Nmr and uv spectrum , Nonlinear optical properties , Nuclear Magnetic Resonance (NMR) , chemical structure , chemistry , dimerization , infrared spectroscopy , nuclear magnetic resonance spectroscopy , Raman spectrometry , ultraviolet spectrophotometry , Dimers