论文部分内容阅读
合成并表征了高氯酸稀土与二苯基亚砜、苯甲酸的四种四元配合物。经元素分析、稀土络合滴定、摩尔电导率及差热-热重分析,表明四元配合物组成为[REL5L′(ClO4)] (ClO4) (RE= La,Pr,Nd,Eu;L=C6H5SOC6H5,L′=C6H5COO-)。在红外光谱中,第一配体二苯基亚砜的νS O的特征吸收峰出现在1 037cm-1处,而各稀土配合物的νS O向低波数移动到984 ～989 cm-1,红移50 cm-1左右,表明稀土离子与亚砜基团的氧原子之间发生配位作用。第二配体苯甲酸钠的反对称伸缩振动吸收峰νas(COO -)出现在1 550 cm-1,对称伸缩振动吸收峰νs(COO -)出现在1 416 cm-1处,羧基伸缩振动吸收频率差Δn[νas(COO -)-νs(COO -)]值为134cm-1;在所有配合物的红外光谱图中νas(COO -)向高波数方向发生了位移,而νs(COO -)向低波数方向发生了位移,并且Δn值均大于钠盐的Δn值,由此可以认为配合物中羧基是通过单齿方式与稀土离子配位。测定了配合物在丙酮溶液中的摩尔电导率,根据配合物在常见有机溶剂中的摩尔电导率与正负离子的关系结合配合物的红外光谱中高氯酸根离子的四条特征吸收带,表明配合物为1:1型电解质,两个ClO4-无机抗衡阴离子,其中一个在外界,一个进入内界与稀土离子配位。配合物的荧光发射光谱表明,四元配合物的荧光强度比二苯基亚砜高氯酸稀土二元配合物的荧光强度提高469%。磷光光谱表明苯甲酸三重态能级的下限和二苯亚砜三重态能级的上限重叠,导致三重态能级范围扩大,由此可见第二配体的加入提高了配体的三重态能级与Eu3 +离子5D0能级的匹配程度。同时在配合物的荧光发射光谱中还可以看到铕离子的电偶极跃迁强度大于磁偶极跃迁,表明稀土离子不处于晶体场的对称中心。在四元配合物中,由于第二配体的加入,往往会降低配合物的对称性,从而增强稀土离子的荧光强度。本文合成的稀土配合物具有良好的荧光性能,而且在室温下稳定,溶解性好,分解温度较高。
Four quaternary complexes of rare earth perchlorate with diphenylsulfoxide and benzoic acid were synthesized and characterized. The results of elemental analysis, rare earth complexometric titration, molar conductivity and differential thermal-thermogravimetric analysis show that the composition of quaternary complex is [REL5L ’(ClO4)] (ClO4) (RE = La, Pr, Nd, Eu; C6H5SOC6H5, L ’= C6H5COO-). In the infrared spectrum, the characteristic absorption peak of the νS O of the first ligand diphenylsulfoxide appeared at 1 037 cm -1, while the νS O of the rare earth complexes shifted to a low wave number from 984 to 989 cm -1, Shift 50 cm-1 or so, indicating that rare earth ions and sulfoxide groups oxygen atoms occur coordination role. The asymmetric stretching vibrational absorption peak νas (COO -) of the second ligand sodium benzoate appeared at 1 550 cm-1, and the symmetrical stretching vibration νs (COO -) appeared at 1 416 cm-1. The stretching frequency of carboxyl stretching vibration The value of Δn [νas (COO -) - νs (COO -)] was 134cm-1. In the IR spectra of all the complexes, νas (COO -) shifted toward the higher wave number. In the low wavenumber direction, the shift occurred, and the value of Δn was greater than the value of Δn of the sodium salt. Therefore, it can be considered that the carboxyl group in the complex is coordinated to the rare earth ions by monodentate. The molar conductivity of the complex in acetone solution was determined. According to the molar conductivity of the complex in the common organic solvent and the relationship between the positive and negative ions, the four characteristic absorption bands of the perchlorate ion in the infrared spectra of the complex were shown. 1: 1 type electrolyte, two ClO4-inorganic counter anions, one of which is in the outside world and the other goes into the inner world to coordinate with rare earth ions. The fluorescence emission spectrum of the complex showed that the fluorescence intensity of the quaternary complex was 469% higher than that of the binary complex of diphenylsulfoxide perchlorate. Phosphorescence spectra show that the lower limit of the triplet energy level of benzoic acid and the upper limit of the triplet energy level of diphenyl sulfoxide overlap, resulting in the widening of the triplet energy level. Thus, the addition of the second ligand increases the triplet energy level of the ligand And Eu3 + ion 5D0 level match. At the same time, it can also be seen in the fluorescence emission spectrum of the complex that the electric dipole transition of europium ions is stronger than that of magnetic dipole transitions, indicating that the rare earth ions are not in the symmetry center of the crystal field. In the quaternary complex, due to the addition of the second ligand, the symmetry of the complex tends to be reduced, thereby increasing the fluorescence intensity of rare earth ions. The rare earth complexes synthesized in this paper have good fluorescence properties, but also stable at room temperature, good solubility, high decomposition temperature.