Division of Chemistry, Bialystok University of Technology, Zamenhofa 29, 15-435 Bialystok, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Feb 15;103:456-66. doi: 10.1016/j.saa.2012.11.073. Epub 2012 Dec 5.
The influence of alkaline earth metal ions on the electronic system of 4-nitrobenzoic acid was studied in this paper. The vibrational (FT-IR) and NMR ((1)H and (13)C) spectra were recorded for 4-nitrobenzoic acid (4-nba) and its salts (4-nb). The assignment of vibrational spectra was done. Some shifts of band wavenumbers in alkaline earth metal 4-nitrobenzoates spectra were observed in the series from magnesium to barium salts. Good correlations between wavenumbers of the vibrational bands in the IR spectra of studied salts and ionic potential, electronegativity, inverse of atomic mass, ionic radius and ionization energy of studied metals were found. The regular changes in the chemical shifts of protons ((1)H NMR) and carbons ((13)C NMR) in the series of studied salts were also observed. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G(**) as well as LANL2DZ basis sets. Theoretical wavenumbers and intensities in IR and chemical shifts in NMR spectra were also obtained. The calculated parameters were compared with experimental data of studied compounds.
本文研究了碱土金属离子对 4-硝基苯甲酸（4-NBA）及其盐（4-NB）电子体系的影响。记录了 4-硝基苯甲酸（4-NBA）及其盐（4-NB）的振动（FT-IR）和 NMR（1H 和 13C）谱。对振动光谱进行了归属。在从镁到钡盐的系列中，观察到碱土金属 4-硝基苯甲酸盐光谱中一些带的波数发生了位移。在研究的盐的红外光谱中，振动带的波数与离子势、电负性、原子质量倒数、离子半径和研究金属的电离能之间存在很好的相关性。在研究的盐系列中，质子（1H NMR）和碳（13C NMR）的化学位移也观察到了规则的变化。采用 B3LYP 方法，使用 6-311++G（**）和 LANL2DZ 基组，对研究化合物的优化几何结构进行了计算。还得到了红外光谱中的理论波数和强度以及 NMR 谱中的化学位移。计算参数与研究化合物的实验数据进行了比较。
