基于吡啶羧酸与己二酸体系的钕MOFs的合成及性能研究

A metal-organic framework constructed with pyridine carboxylic and adipic acid: Synthesis,structures,and properties

以Nd Cl_3·6H_2O、2,2'-联吡啶-3,3'-二羧酸(H_2bpdc)、己二酸(adi)为原料,用水热法合成了一种新型双配体单金属MOFs材料[Nd_2(bpdc)_2(adi)(H_20)_6]_n,该材料晶体呈粉色片状。讨论了反应物配比、溶剂种类与用量、体系p H、温度与降温速率对MOFs材料合成的影响,最终确定最佳合成条件为:反应物配比n(Nd^(3+))∶n(bpdc^(2-))∶n(adi^(2-))=2∶3∶3,以去离子水为溶剂,溶剂量为8 m L,p H=4,145℃恒温96 h,以1℃/h速度降温。采用红外光谱、X-射线单晶衍射、热重TG和紫外可见漫反射对材料的结构、热稳定性和导电性能进行测试,结果表明:产物晶体为三斜晶系,Pī空间群;在197℃以下材料可以稳定存在;材料具有良好的绝缘特性,可以用作绝缘材料。

A new metal-organic framework（ [Nd_2（ bpdc）_2（ adi）（ H_2O）_6]_n） has been synthesized by reacting Nd Cl_3·6H_2O,2,2＇-bipyridyl-3,3＇-dicarboxylate（ H_2bpdc） and adipic acid under hydrothermal conditions. The products are pink sheet-like crystals. The effects of varying synthesis parameters such as the ratio of reactants,nature and amount of solvent,p H,temperature and cooling rate have been investigated. The optimal synthetic conditions were found to be n（ Nd3＋） ∶ n（ bpdc2-） ∶ n（ adi2-） = 2∶ 3∶ 3,8 m L H_2 O as the solvent,p H = 4,a reaction time of 96 h at a constant temperature of 145 ℃ followed by cooling at a rate of 1 ℃/h. The structure,thermal stability and conductivity of the material were determined by IR,powder XRD,single crystal X-ray diffraction,TG and UV-Vis DRS. The crystal is triclinic,space group P ī,is thermally stable below 197 ℃ and has insulating properties.