Division of Chemistry, Bialystok University of Technology, Zamenhofa 29, 15-435 Białystok, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Jan 1;100:21-30. doi: 10.1016/j.saa.2012.01.048. Epub 2012 Feb 14.
The effect of some metals on the electronic system of benzoic and nicotinic acids has recently been investigated by IR, Raman and UV spectroscopy [1-3]. Benzoic and nicotinic acids are regarded model systems representing a wide group of aromatic ligands which are incorporated into enzymes. In this work the FT-IR (in solid state and in solution), FT-Raman, UV absorption and (1)H and (13)C NMR spectra of caffeic acid (3,4-dihydroxycinnamic acid) and its salts with lithium, sodium, potassium, rubidium and caesium were registered, assigned and analyzed. The effect of alkali metals on the electronic system of ligands was discussed. Studies of differences in the number and position of bands from the IR, Raman, UV absorption spectra and chemical shifts from NMR spectra allowed to conclude on the distribution of electronic charge in the molecules, the delocalization energy of π electrons and the reactivity of ligands in metal complexes. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G** basis set. Bond lengths, angles and dipole moments for the optimized structures of caffeic acid and lithium, sodium, potassium caffeinates were also calculated. The theoretical wavenumbers and intensities of IR spectra were obtained. The calculated parameters were compared to the experimental characteristics of investigated compounds. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris.
最近，通过红外、拉曼和紫外光谱研究了一些金属对苯甲酸和烟酸电子体系的影响[1-3]。苯甲酸和烟酸被认为是代表广泛芳香配体基团的模型体系，这些配体被纳入酶中。在这项工作中，记录、分配和分析了咖啡酸（3,4-二羟基肉桂酸）及其与锂、钠、钾、铷和铯的盐的傅里叶变换红外（固态和溶液）、傅里叶变换拉曼、紫外吸收和（1）H 和（13）C NMR 光谱。讨论了碱金属对配体电子体系的影响。对来自红外、拉曼、紫外吸收光谱和 NMR 光谱的谱带数量和位置的差异的研究，使我们能够得出关于分子中电子电荷分布、π电子离域能和金属配合物中配体反应性的结论。采用 B3LYP 方法，使用 6-311++G**基组计算了研究化合物的优化几何结构。还计算了咖啡酸和锂、钠、钾咖啡酸盐优化结构的键长、键角和偶极矩。获得了红外光谱的理论波数和强度。将计算参数与研究化合物的实验特性进行了比较。测试了研究化合物对大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌和普通变形杆菌的微生物活性。
