氨基酸DLH及其稀土镧配合物的高压红外和拉曼光谱研究  

Infrared and Raman Spectra Studies of DL-Homocysteic Acid (DLH) and Its Lanthanum Complex at High External Pressure

作　　者：李维红[1] 许振华[1] 吴瑾光[1] Butler I S 

机构地区：[1]北京大学化学与分子工程学院 [2]Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Canada H3A 2K6

出　　处：《光谱学与光谱分析》2005年第9期1388-1392,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金青年基金(29901002)资助项目

摘　　要：测定了DL-2-氨基-4-磺酸基-丁酸[DLH,DL-Homocysteicacid,(NH3+)-CH(COOH)-(CH2)2-SO3-]及其稀土La配合物[La(DLH)2Cl3·H2O=LaL2]在不同压力下的红外和拉曼光谱。DLH在50kbar左右压力以下存在两个压力诱导相转变区,它们分别在17和37kbar左右,两者均为二级相转变,认为分子间氢键的存在是出现两个压力诱导相转变区的原因。在红外光谱中,SO3-的对称伸缩振动的压力灵敏度(dν/dp)表现出与其他振动模式不同的变化趋势,它们在低压相区的平均压力灵敏度为0.30cm-1·(kbar)-1、中压相区为0.32cm-1.(kbar)-1、高压相区为0.41cm-1·(kbar)-1,低压相区与高压相区的比值为0.72,而其他振动模式刚好相反,低压相区与高压相区的比值为4.8。稀土La配合物LaL2的生成,改变了分子间的氢键,在50kbar左右压力以下只观察到1个压力诱导相转变区(27kbar附近)。在红外光谱中,配合物LaL2中SO3-的反对称伸缩振动的压力灵敏度(dν/dp)也表现出与其他振动模式不同的变化趋势,它们在低压相区的平均压力灵敏度与高压相区的平均压力灵敏度的比值为0.43,而其他振动模式的比值为2.5。DL-Homocysteic acid（DLH, （NH3）-CH（CA[IOH）-（CH2 ）2-SO3^- ） is extensively in existence as free amino-acid in the centralnervous system of mammal. The infrared （IR） and Raman spectra of DL-Homocysteic acid （DLH） and its La complex [La （DLH）2Cl3· H2O= LaL2] were measured at high external pressure. The DLH has two pressure-induced phase transitions （near 17 kbar and 37 kbar） and three pressure-phase areas below 50 kbar for there are ten intermolecular hydrogen bonds between the DLH molecules. But there is only one pressure-induced phase transition （near 27 kbar ） to be observed in the complex LaL2. These show that the ten intermolecular hydrogen bonds of the DLH molecules changed due to the formation of complex LaL2. In infrared spectra, the changing trend of the pressure sensitivities （dv/dp） of symmetry stretching of SOs in DLH and asymmetry stretching of SO3^- in LaL2 are very different from the other vibrational modes when both compounds undergo high external pressure. In infrared spectra, the average pressure sensitivities of symmetry stretching of SO3^- are ： low-pressure phase area （0.30 cm^-1. （kbar^）- 1 ）〈 middle-pressure phase area （0.32 cm^-1 · （kbar）^-1 ）〈high-pressure phase area（0.41 cm^-1·（kbar）^-1 ）, but 0.86 cm^- 1· （kbar）^-1 （low-pressure phase area） 〉0.64 cm^-1. （kbar）^-1 （middle-pressure phase area）〉0.26 cm^-1 · （kbar）^-1 （high-pressure phase area） to other vibrational modes in DLH. The average pressure sensitivities of asymmetry stretching of SO3^- in LaL2 are lower in low-pressure phase area than in high-pressure phase area, but the average pressure sensitivities of other modes are higher in low-pressure phase area than in high-pressure phase area.

关 键 词：红外光谱 拉曼光谱 氨基酸 高压 相变 压力灵敏度 

分 类 号：O657.3[理学—分析化学]