摘要
本文以间苯二甲酸(H_(2)IPA)和1,3,5-三(1-咪唑基)苯(TIB)为混合配体,硝酸钴为金属源,通过溶剂热法合成了一例新型二维钴金属有机框架化合物{[Co(IPA)(TIB)]·2H_(2)O}_(n)(Co-MOF)。通过单晶X射线衍射、粉末X射线衍射、红外光谱、热重分析及荧光光谱等手段对其结构和性能进行了系统表征。单晶衍射结果表明,该Co-MOF属于单斜晶系,空间群为P2_(1)/c,晶胞参数为a=0.96428(7)nm,b=1.28298(10)nm,c=1.78332(14)nm。其不对称单元结构包含1个Co(Ⅱ)离子、1个脱质子的IPA^(2-)配体、1个TIB中性配体和2个结晶水分子。IPA^(2-)配体和TIB配体都通过μ_(2)-η^(1):η^(1)桥联方式键合2个Co^(2+),形成一四配位的扭曲四面体CoN_(2)O_(2)构型。这些CoN_(2)O_(2)次小结构单元,进一步由倒反对称相关联的IPA^(2-)和TIB配体连接,形成二维梯状钴基金属有机框架结构。拓扑结构分析表明该二维Co-MOF可简化为Schläfli符号为(4^(4).6^(2))的(4,4)-连接的sql网格结构。此外,Co-MOF层与层之间存在由TIB配体中对称相关联咪唑环间所形成的强π-π堆积作用,将二维Co-MOF层拓展为三维超分子结构。荧光实验研究表明,该Co-MOF对水中的3种多氧酸根阴离子Cr_(2)O_(7)^(2-)、CrO_(4)^(2-)、S_(2)O_(8)^(2-)和Fe^(3+)展现出高选择性和高灵敏的荧光猝灭响应,其检测限分别为2.007×10^(-4)、2.514×10^(-4)、8.331×10^(-4)和2.709×10^(-4)mol/L。得益于开放的金属位点和其中未参与配位的咪唑基团,该Co-MOF兼具优异的热稳定性与荧光传感性能,在环境污染物检测领域具有广泛的潜在应用价值。
A new two-dimensional cobalt-based metal-organic framework(Co-MOF)with the formula{[Co(IPA)(TIB)]∙2H_(2)O}_(n),was successfully synthesized through solvothermal method using isophthalic acid(H_(2)IPA)and 1,3,5-tris(1-imidazolyl)benzene(TIB)as mixed ligands,and cobalt nitrate as metal source.Its crystal structure and properties were fully characterized by single-crystal X-ray diffraction(SCXRD),powder X-ray diffraction(PXRD),infrared spectroscopy(IR),thermogravimetric analysis(TGA),and fluorescence spectroscopy.The SCXRD determination reveals that the Co-MOF crystallizes in the monoclinic system with space group P2_(1)/c,and with the unit cell parameters of a=0.96428(7)nm,b=1.28298(10)nm,and c=1.78332(14)nm.The asymmetric unit of Co-MOF contains a Co(Ⅱ)ion,a deprotonated IPA^(2-)anion ligand,a neutral TIB ligand,and two crystalline H_(2)O molecules.Notably,both IPA^(2-)and TIB ligands were observed to coordinate two Co^(2+)by a μ_(2)-η^(1):η^(1) bridging mode,forming a distorted tetrahedral CoN_(2)O_(2) secondary building unit.These structural units were further interconnected via inversion-related IPA^(2-)and TIB ligands,resulting in a two-dimensional ladder-type framework.Topologically,the 2D network of Co-MOF can be simplified as a(4,4)-connected sql network with a Schläfli symbol of(44.62).Furthermore,the adjacent 2D layers were extended to a three-dimensional supramolecular architecture with strongπ-πstacking interactions between the symmetry-related imidazole rings of TIB ligand.The fluorescence investigations indicate that this Co-MOF exhibits high selectivity and sensitivity for detecting three polyoxoanions(Cr_(2)O_(7)^(2-),CrO_(4)^(2-),and S_(2)O_(8)^(2-))and Fe^(3+) in aqueous solutions,with the calculated detection limits of 2.007×10^(-4),2.514×10^(-4),8.331×10^(-4),and 2.709×10^(-4) mol/L,respectively.The Co-MOF has excellent thermal stability and fluorescence sensing performance,which may be accounted for the presence of open metal sites and uncoordinated imidazole groups of TIB ligand.These combined characteristics suggest that the Co-MOF possesses significant potential for environmental pollutant detection applications.
作者
陈文涛
庄杏宜
安航宜
来中杰
王爱荣
罗亚妮
史忠丰
李家明
CHEN Wentao;ZHUANG Xingyi;AN Hangyi;LAI Zhongjie;WANG Airong;LUO Yani;SHI Zhongfeng;LI Jiaming(Guangxi Key Laboratory of Green Chemical Materials and Safety Technology,College of Petroleum and Chemical Engineering,Beibu Gulf University,Qinzhou 535011,China;Department of Economics,Beibu Gulf Vocational and Technical School,Qinzhou 535000,China)
出处
《人工晶体学报》
北大核心
2025年第9期1642-1653,共12页
Journal of Synthetic Crystals
基金
广西自然科学基金(2025GXNSFAA069072,2025GXNSFHA069144)
广西重点研发计划(桂科自AB25069382)
广西教育厅高校科研项目(2025KY0481)
北部湾大学高层次人才项目(24KYQD04)
广西研究生教育创新计划项目(YCSW2025621)
国家自然科学基金(22065001)
广西绿色化工新材料与安全技术重点实验室(2023ZZKT01)。
关键词
钴(Ⅱ)金属有机框架
晶体结构
荧光传感
猝灭常数
多氧酸根离子
铁(Ⅲ)离子
cobalt(II)metal-organic framework
crystal structure
fluorescence sensing
quenching constant
polyoxoanion recognition
iron(Ⅲ)ion
