阴离子插层镁铝水滑石结构及相互作用的理论研究

采用密度泛函理论(DFT)计算了MgAl-LDHs层板与无机阴离子(F^-、Cl^-、NO₃^-、CO₃^2-、SO₄^2-)和有机阴离子(水杨酸根离子(HO(C₆H₄)COO]^-)、苯甲酸根离子((C₆H₅)COO]^-)、对二甲氨基苯甲酸根离子(p-(CH₃)₂N(C₆H₄)COO]^-)、十二烷基磺酸根离子C₁₂H₂₅SO₃]^-、己烷基磺酸根离子C₆H₁₃SO₃]^-、丙烷基磺酸根离子C₃H₇SO₃]^-)间的相互作用,获得稳定超分子几何结构及相互作用能。层板主体与客体间存在较强的超分子作用,包括主客体间静电作用和氢键等。主、客体间相互作用能数值大小顺序为CO₃^2- > SO₄^2- > F^-> Cl^-> NO₃^-;p-(CH₃)₂N(C₆H₄)COO]^-> (C₆H₅)COO]^-> HO(C₆H₄)COO]^-和C₁₂H₂₅SO₃]^-> C₆H₁₃SO₃]^- > C₃H₇SO₃]^-。另外,还采用自然键轨道(NBO)计算和分析了LDHs 层板与阴离子间作用机理,从二阶微扰理论计算得到的稳定化能变化趋势与相互作用能数据基本吻合。

Theoretical investigation on the structure of anions intercalated MgAl-layered double hydroxides and the interaction between anions and host layer

The structure of anion-intercalated MgAl-layered double hydroxides (MgAl-LDHs) and the interaction between the anion and host layer were investigated by density functional theory (DFT); the anions considered were inorganic ones like F^-, Cl^-, NO₃^-, CO₃^2- and SO₄^2-, as well as organic ones like p-(CH₃)₂N(C₆H₄)COO]^-, (C₆H₅)COO]^-, HO(C₆H₄)COO]^-, C₁₂H₂₅SO₃]^-, C₆H₁₃SO₃]^- and C₃H₇SO₃]^-. The geometric structures and interactional energies between the anions and host layer were obtained. The results showed that there is a strong supra-molecular interaction between anions and host layer of MgAl-LDHs and the interactional energy values followed the orders of CO₃^2- > SO₄^2- > F^- > Cl^- > NO₃^-, p-(CH₃)₂N(C₆H₄)COO]^- > (C₆H₅)COO]^- > HO(C₆H₄)COO]^-, and C₁₂H₂₅SO₃]^- > C₆H₁₃SO₃]^- > C₃H₇SO₃]^-. In addition, the interaction mechanism between anions and host layer was considered by the natural bond orbital (NBO) analysis; the trend of stability energies calculated by the second order perturbation agrees well with that of the interactional energies.