DFT, FT-Raman, FT-IR, solution and solid state NMR studies of 2,4-dimethoxyphenylboronic acid
DFT, FT-Raman, FT-IR, solution and solid state NMR studies of 2,4-dimethoxyphenylboronic acid
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DOI：
10.1016/j.crci.2010.11.005
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发表时间：
2011-05-01
影响因子：
1.6
通讯作者：
Alver, Ozgur
中科院分区：
文献类型：
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作者：
Alver, Ozgur
本文用FT-IR、拉曼、溶液和固体NMR等方法对2，4-二甲氧基苯硼酸（2，4-dmpba）可能的稳定形态和分子结构进行了实验和理论研究。在4000-400 cm（-1）范围内记录了FT-IR和拉曼光谱。本文报道了2，4-dmpba（（CH_3 O）（2）C_6 H_3- B（OH）（2））的C ~（13）交叉极化魔角旋转NMR和溶液相H ~（11）、C ~（13）和HETCOR NMR谱。采用Becke-3-Lee-Yang-Parr（B3 LYP）杂化密度泛函理论方法，在6-31++G（d，p）基组水平上，研究了在势能面上以最小值为目标的优化几何结构.采用密度泛函B3 LYP方法，在6-31++G（d，p）基组下计算了2，4-dmpba的振动波数和1H，13 CNMR化学位移.基于标度量子力学（SQM）方法计算的总能量分布（TED），对分子的振动进行了可靠的归属。实验结果与理论计算结果的比较表明，密度泛函B3 LYP方法能够较好地预测振动波数和核磁屏蔽张量.此外，已发现具有Cs点基团的顺-反（ct）形式的2，4-dmpba是最稳定的构象体。(C)2010年科学院。由Elsevier Masson SAS出版。All rights reserved.
The possible stable forms and molecular structures of 2,4-dimethoxyphenylboronic acid (2,4-dmpba) have been experimentally and theoretically studied using FT-IR. Raman and solution and solid state NMR spectroscopic methods. FT-IR and Raman spectra were recorded in the region of 4000-400 cm(-1). C-13 cross-polarization magic-angle spinning NMR and solution phase H-1, C-13 and HETCOR NMR spectra of 2,4-dmpba ((CH3O)(2)C6H3- B(OH)(2)) have been reported. The optimized geometric structures concerning to the minimum on the potential energy surface was investigated by Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional theory method together with 6-31++G(d,p) basis set. The vibrational wavenumbers and 1H, 13C NMR chemical shifts of 2,4-dmpba have been calculated by means of B3LYP density functional methods with 6-31++G(d,p) basis set. Reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method. Comparison between the experimental and the theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers and nuclear magnetic shielding tensors. Furthermore, the cis-trans (ct) form of 2,4-dmpba with Cs point group has been found to be the most stable conformer. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.