Balachandran V, Santhi G, Karpagam V, Revathi B, Karabacak M
Centre for Research, Department of Physics, AA Government Arts College, Musiri, Tiruchirappalli 621211, India.
Department of Physics, Government Arts College, Karur 639005, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt B:451-63. doi: 10.1016/j.saa.2014.09.057. Epub 2014 Sep 28.
The optimized molecular structure and corresponding vibrational assignments of 2-tert-butyl-5-methyl anisole (TBMA) have been investigated using density functional theory (DFT)/B3LYP with 6-31G(d,p) and 6-311++G(d,p) basis sets investigation of the relative orientation of the methoxy group has shown two conformers (O-cis) and (O-trans) exist. The vibrational analysis of the stable conformer of the title compound is performed by means of infrared absorption and Raman spectroscopy in combination with theoretical simultaneously. The natural bond orbital (NBO) analysis is useful to understand the intra-molecular hyper conjugative interaction lone pair and π(∗)(C-C), σ(∗)(C-H) bond orbital. HOMO and LUMO energies show that charge transfer occurs in the molecule, therefore; HOMO, LUMO and molecular electrostatic potential (MEP) were calculated and analyzed. (1)H and (13)C NMR spectra by using gauge including atomic orbital (GIAO) method of studied compound were compared with experimental data. The thermodynamic functions of TBMA were calculated by B3LYP/6-311+G(d,p) basis set.
采用密度泛函理论（DFT）/B3LYP方法，结合6-31G(d,p)和6-311++G(d,p)基组，对2-叔丁基-5-甲基苯甲醚（TBMA）的优化分子结构及相应的振动归属进行了研究。对甲氧基相对取向的研究表明存在两种构象异构体（O-顺式）和（O-反式）。通过红外吸收光谱和拉曼光谱并结合理论计算，对标题化合物稳定构象异构体进行了振动分析。自然键轨道（NBO）分析有助于理解分子内超共轭相互作用、孤对电子以及π*(C-C)、σ*(C-H)键轨道。最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能量表明分子中发生了电荷转移，因此，计算并分析了HOMO、LUMO和分子静电势（MEP）。采用含原子轨道的规范（GIAO）方法，将所研究化合物的(1)H和(13)C核磁共振谱与实验数据进行了比较。采用B3LYP/6-311+G(d,p)基组计算了TBMA的热力学函数。
