硅钨酸晶体合成和谱学研究及与罗丹明B复合反应探索  

Syntheses and Spectral Study of the Polyoxosilicotungstate and Its Complex Reaction With RhB

作　　者：孙瑞卿 石林 陈义平 孙燕琼 SUN Rui-qing;SHI Lin;CHEN Yi-ping;SUN Yan-qiong(Department of Chemistry,Fuzhou University,Fuzhou 350116,China)

机构地区：[1]福州大学化学学院,福建福州350116

出　　处：《光谱学与光谱分析》2021年第8期2455-2461,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21971040)资助。

摘　　要：通过水热法合成新型硅钨酸化合物[Cu(en)_(2)(H_(2)O)]n{[Cu(en)_(2)][SiW_(12)O_(39.5)]}n(OH)n·n(en)。化合物属于三斜晶系,P空间群,呈一维双链结构,配体与簇阴离子间的氢键构成二维层状结构,层与层之间通过游离的乙二胺(en)分子、羟基与簇阴离子间的强氢键作用连结成三维超分子。利用X射线粉末衍射、红外光谱、磁微扰及热微扰下的二维红外光谱、固体紫外可见漫反射光谱和热重分析等方法对化合物进行研究。X射线粉末衍射(XRD)显示,化合物测试谱图和单晶结构数据模拟谱图主要峰位重合,峰形基本一致,表明合成的化合物较纯。红外光谱(FTIR)显示,在1100~700 cm^(-1),出现了饱和Keggin结构4个特征振动吸收峰,3600~3300 cm^(-1)处ν_(as)(O—H)吸收峰由于形成氢键峰出现了宽化;5~50mT磁场变化下的2D-IR COS显示,890,800和780 cm^(-1)处较强的磁响应峰分别为ν_(s)(W O d),ν(W—O_(b)—W)和ν(W—O_(c)—W),这是由于磁性粒子Cu与簇阴离子上的端氧配位导致钨氧骨架伸缩振动时偶极矩随磁场发生变化;50~120℃热微扰2D-IR COS显示,920 cm^(-1)处出现很强的ν_(as)(W O_(d))响应峰,762 cm^(-1)处的ν(W—O_(b)—W)和748 cm^(-1)处的ν(W—O_(c)—W)响应峰相对较弱,验证了结构分析中簇笼上端氧形成的氢键比桥氧的氢键多,强氢键作用导致整个簇阴离子骨架对热响应敏感;固体紫外-可见漫反射(UV-Vis DRS)光谱表明,化合物分别在309和558 nm处出现了O→W的LMCT跃迁和Cu^(2+)的d→d跃迁。热重分析(TGA)显示,失重过程分为3个阶段,第1阶段主要失去游离的乙二胺分子和羟基,第2阶段失去配位乙二胺和配位水,第3阶段540℃后,钨氧簇骨架开始坍塌。探讨不同pH条件下化合物与染料罗丹明B(RhB)的复合反应情况,实验表明强酸性条件有利于复合反应,生成紫色复合物沉淀,在pH 1时绘制RhB的标准浓度曲线,并利用紫外吸收光谱检测复合反应后试液�A novel triclinic polyoxosilicotungstate[Cu(en)_(2)(H_(2)O)]n{[Cu(en)_(2)][SiW_(12)O_(39.5)]}n(OH)_(n)·n(en)was hydrothermally synthesized with P 1 space group and a one-dimensional double chains structure.The hydrogen bonds between ligands and cluster anions formed a two-dimensional layered structure.The layers were connected to form a three-dimensional supramolecule by strong hydrogen bonds between free en molecules,hydroxyls and cluster anions.The compound was characterized by XRD,FTIR,two-dimensional(2D)correlation infrared spectroscopy under magnetic and thermal perturbation,UV-Vis DRS spectrum and TG etc.XRD showed that the spectrum was basically consistent with the simulation by single crystal structure data,and the main peaks were the same,indicating that the synthesized compound was relatively pure.The FT-IR spectrum indicated that there was four characteristic stretching vibration of Keggin cluster anion skeleton in the range of 1100 to 700 cm^(-1),theν_(as)(O—H)at 3600~3300 cm^(-1)was broadened due to the formation of hydrogen bonds.Furthermore,the two-dimensional infrared correlation spectroscopy under 5~50 mT magnetic showed that the strong response peaks at 890,800 and 780 cm^(-1)wereν_(s)(W O_(d)),ν(W—O_(b)—W)andν(W—O_(c)—W)respectively.This might be caused by the coordination between magnetic Cu and O d of cluster anion,which led to the variation of the dipole moment of W—O skeleton stretching vibration with magnetic.The 2D-IR COS under 50~120℃illustrated that there was a strongν_(as)(W=O_(d))response peak at 920 cm^(-1),whileν(W—O_(b)—W)at 762 cm^(-1)andν(W—O_(c)—W)at 748 cm^(-1)was relatively weak,which verified that the hydrogen bonds formed by O_(d)were more than those of O_(b)in the structural analysis.The strong hydrogen bonding made the whole cluster anion skeleton more sensitive to the thermal response.UV-Vis DRS found the Oμ→W(LMCT)and d→d transition of Cu^(2+)happened at 309 and 558 nm respectively.TGA showed that the weight loss process could be divide

关 键 词：硅钨酸 KEGGIN结构 二维红外光谱 复合物 

分 类 号：O644.1[理学—物理化学]