【作者】 杨轶颖；

【导师】 蒲敏；

【作者基本信息】 北京化工大学 ， 物理化学， 2009， 硕士

【摘要】 本文采用量子化学的密度泛函理论(DFT),研究了偶氮苯羧酸衍生物(偶氮苯甲酸、偶氮苯乙酸和甲基红)插层Zn/Al水滑石的结构及其性质。一方面通过研究甲基红的顺反异构反应揭示偶氮苯羧酸衍生物的稳定性;另一方面采用分子碎片组合计算方法构建出偶氮苯羧酸衍生物插层水滑石体系的理论模型。使用B3LYP方法,在6-31G(d,p)和6-311++G(d,p)级别上研究了甲基红的顺反异构反应机理。发现有两条反应路径,这两条路径都是既包含CNNC旋转又包含NNC反转的混合路径,并通过角度变化来说明旋转和反转对反应的贡献大小。使用B3LYP和B3PW91方法,分别在6-31G(d,p)级别上计算了Zn/Al层板单元、偶氮苯甲酸、偶氮苯乙酸和甲基红的阴离子的电子结构,并优化得到它们分别与Zn/Al层板的主-客体相互作用体系的稳定结构。从能量、前线轨道分布等方面分析表明,以上各阴离子均易于与层板相结合形成插层结构,且插层后有利于提高客体的稳定性。以偶氮苯甲酸、偶氮苯乙酸的聚集行为来进一步研究层间客体之间的相互作用,用B3LYP方法,在LANL2DZ和6-31G(d,p)水平上分别优化得到芳环以平行方式堆积而成的二聚体的稳定构型,它们能近似地反映客体阴离子在水滑石层间的聚集状态。采用分子碎片组合计算方法,将分子碎片(客体-客体相互作用碎片二聚体分子和主体-客体相互作用碎片偶氮苯甲酸-Zn/Al层板、偶氮苯乙酸-Zn/Al层板)通过它们之间的紧密联系,较合理地构建出偶氮苯甲酸插层水滑石和偶氮苯乙酸插层水滑石的理论结构模型。它们在水滑石层间都为双层插层排列,得到层间距的理论值分别为1.99nm、1.78nm。更多还原

【Abstract】 The structures and properties of azobenzoic acid derivatives (4-(phenylazo)-benzoic acid(AzBA), (4-phenylazophenyl)-acetic acid(AzAA) and methyl red(MR))-intercalated layered double hydroxide (LDHs) have been studied based on density functional theory (DFT) of quantum chemistry. The cis-trans isomerization of MR has been investigated, which shows the stability of azobenzoic acid derivatives. Furthermore, the theoretical models of LDHs have been built with a method named combinational calculation of molecular fragments (CCMF).The cis-trans isomerization mechanism of MR has been studied by B3LYP method at the levels of 6-31G(d,p) and 6-311++G(d,p). The geometries of cis-, tran-MR and the transition states for two pathways have been optimized. It can been found that these paths both are hybrid pathways combined the CNNC rotation and the NNC inversion, and the angle changes in the reaction have shown that how they contribute to the isomerization.From the electronic structures of Zn/Al-lamella, AzBA anion, AzAA anion and MR anion investigated by B3LYP and B3PW91 methods at the 6-31G(d,p) level, the host-guest interaction models can be built. The analysis has shown that the combination of guest anion and lamella is favored in the terms of energy and molecular frontier orbitals. The stability of guest has been enhanced after being intercalated into LDHs.The aggregation of AzBA anion and AzAA anion has facilitated further study of guest-guest interaction. The dimer structures with parallel aromatic stacking are obtained at the levels of LANL2DZ and 6-31G(d,p) with B3LYP method, respectively, which can well reflect the aggregation states of the interlayer guest anions.Finally, the theoretical models of AzBA-LDHs and AzAA-LDHs have been built successfully using the CCMF strategy from the combination of the guest-guest fragments and the host-guest fragments. The theoretical interlayer distances of AzBA-LDHs and AzAA-LDHs are 1.99nm and 1.78nm, respectively.更多还原