Structural and Vibrational Investigation of 1,2-Bis(3,4-Dimethoxyphenyl) Ethane-1,2-Dione (Veratril): Experimental and Theoretical Studies

Abstract

The molecular and crystal structures of 1,2-bis(3,4-dimethoxyphenyl)ethane- 1,2-dione (TMBZ = tetramethoxybenzil) were determined by a single-crystal X-ray diffraction, 1H NMR, and FT-IR spectroscopy. The compound TMBZ (C<inf>18</inf>H<inf>18</inf>O<inf>6</inf>, M <inf>r</inf> = 330.32) crystallized in the orthorhombic Fdd2 space group wherein: a = 39.145(4), b = 18.167(2), c = 4.3139(5) Å and β = 90°, Z = 8. The packing of the molecules in the crystal lattice is stabilized by intermolecular C-H⋯O contacts in the herringbone arrangement. The molecular geometry and harmonic frequencies of TMBZ in the ground state were calculated utilizing density functional (B3LYP) method with the 6-311++G(d, p)-basis set. The density functional theory optimized the geometric structure, and vibrational wave numbers of TMBZ in gas phase were compared with the experimental data. A complete assignment of the fundamentals was proposed based on the total energy distribution calculation. © 2008 Springer Science+Business Media, LLC.