基于2,6-二(4-羧基苯亚甲基)环己酮的金属-有机框架化合物的合成与表征

以2,6-二(4-羧基苯亚甲基)环己酮(H₂L)为配体得到一例锰金属-有机框架化合物MnL]_n,并运用红外、热重、循环伏安、固体紫外、X射线光电子能谱和X射线单晶衍射对其进行表征。单晶衍射分析表明该配合物属于三斜晶系,空间群P1^-,不对称单元由Mn(Ⅱ)离子和一个L^2-配体组成。配体两端的羧基均为单齿配位,配体中间羰基上的氧参与配位,每个配体L^2-和3个Mn.离子配位,形成相对稳定的三角形配位构型。配合物中的Mn.与氧原子形成六配位构型,其中赤道面中的4个氧原子来自4个配体L^2-中单齿配位的羧基,上下顶点的2个氧原子分别来自配体L^2-中的羰基,从而形成八面体构型MnO₆]。拓扑分析表明该金属-有机框架化合物具有二维kgd结构特征。循环伏安测试表明在扫速为30 mV·s^-1时,半波电位为171 mV,固体紫外光谱表明该化合物的带隙为1.76 eV。该化合物在染料分子如亚甲基蓝、甲基橙的降解过程中,具有一定的光催化活性。

Synthesis and Characterization of Metal-Organic Framework Based on 2,6-Bis(4-carboxybenzylidene)cyclohexanone

By virtue of 2,6-bis(4-carboxybenzylidene)cyclohexanone(H₂L)as the ligand,metal-organic frameworkMnL]_nhas been successfully fabricated.This compound has been characterized by FT-IR,powder X-ray diffraction,cyclic voltammogram,solid UV,X-ray photoelectron spectroscopy and single-crystal X-ray diffraction.It crystalizes in triclinic system with space group P1^-,and the asymmetric unit is composed of one Mn(Ⅱ)ion and one ligand.The carboxyl groups at both ends of the ligand are monodentate coordination,and the oxygen on the carbonyl group in the middle of the ligand coordinate with the central ion as well.Each ligand is coordinated with three Mn(Ⅱ)ions and consequently,achieving a relatively stable triangular coordination configuration.The Mn(Ⅱ)ion forms a six-coordinated configuration with oxygen atoms from six different ligands,i.e.,those four O atoms in the equatorial plane derived from four different ligands′carboxyl groups,the other two O atoms on the two vertices from the differ-ent ligands′carbonyl groups,respectively.As a consequence,the octahedral configurationMnO₆]unit is formed.Based on the topological analysis,its two-dimensional(2D)kgd structural character could be observed.The cyclic voltammogram showed that the half-wave potential,E_1/2=(E_cp+E_ap)/2,was 171 mV when the sweep speed was 30 mV·s^-1.The solid UV absorption spectra showed the band gap was~1.76 eV.Photocatalytic activity has been observed in the process of degrading of dye molecules such as methylene blue and methyl orange.CCDC:2045728.