The efficacy and mode of action of five chalcone-based imidazole derivatives as corrosion inhibitors of aluminium metal in gas-phase and acidic medium have been investigated herein via quantum chemical calculations. D...The efficacy and mode of action of five chalcone-based imidazole derivatives as corrosion inhibitors of aluminium metal in gas-phase and acidic medium have been investigated herein via quantum chemical calculations. Dispersion-corrected DFT (DFT-D3) and time-dependent DFT (TD-DFT) calculations were performed at PBE0/def2-TZVP//PBEh-3c and CAM-B3LYP/def2- TZVP levels of theory, respectively. Conceptual DFT, the quantum theory of atoms-in-molecules (QTAIM) and local energy decomposition (LED) analyses have been performed. The LED analysis was performed at the coupled-cluster singles and doubles with perturbative triples (CCSD(T))/def2-SVP level of theory. Frontier molecular orbital energy gaps calculated using the TD-DFT method are found to lie in the range 3.574 - 4.444 eV, indicative of good adsorption and corrosion inhibition efficacies of the investigated molecules. The interactions between aluminium and the inhibitor molecules studied are found to be energetically favorable, owing to negative computed interaction energy values. Furthermore, QTAIM analysis revealed metal-carbon, metal-oxygen and metal-nitrogen interactions in the inhibitor-aluminium complexes, which are predominantly electrostatic in character, according to LED analysis results. Calculated proton affinities (PAs) have revealed the anticorrosion potentials of the investigated inhibitors in acidic medium, with a noticeable dependency on temperature within the range 273.15 - 343.15 K.展开更多
为探索四聚吡咯配体和低价铀离子相互作用,以实验合成单层三明治结构配合物PcU~ⅥPc(Pc=酞菁)为基础,设计双层三明治型PzU^mPzU^mPz(m=Ⅲ,Ⅳ,Pz=氮杂卟啉),采用相对论密度泛函理论考察了其几何结构、异构体相对稳定性以及成键和轨道性质...为探索四聚吡咯配体和低价铀离子相互作用,以实验合成单层三明治结构配合物PcU~ⅥPc(Pc=酞菁)为基础,设计双层三明治型PzU^mPzU^mPz(m=Ⅲ,Ⅳ,Pz=氮杂卟啉),采用相对论密度泛函理论考察了其几何结构、异构体相对稳定性以及成键和轨道性质.得到se(staggered-eclipsed)和es(eclipsed-staggered)2种类型稳定空间异构体,并进一步优化其所有可能的电子自旋态异构体.计算结果表明,这些低价铀配合物均具有五重态基态.分子中的原子量子理论(quantum theory of atoms in molecule,QTAIM)在U—N键临界点处的电子/能量密度拓扑分析显示U—N键为弱极性共价键.四价配合物拥有4个U(5f)性质高能占据轨道,与2个U4+的5f单电子数相一致;而三价配合物有很大配体参与作用.2个铀原子和中间Pz配体质心近似成线性,这与配合物具有稳定的σ(U—U)成键轨道密切相关.展开更多
在UB3LYP/6-311++G(3df,3pd)水平下,详细研究了Ni活化NH3分子的单重态和三重态势能面,并用分子中的原子量子理论(Quantum Theory of Atom-in-Molecular,QTAIM)计算了势能面上所有驻点的性质.计算结果表明,单重态势能面有两条反应途径,...在UB3LYP/6-311++G(3df,3pd)水平下,详细研究了Ni活化NH3分子的单重态和三重态势能面,并用分子中的原子量子理论(Quantum Theory of Atom-in-Molecular,QTAIM)计算了势能面上所有驻点的性质.计算结果表明,单重态势能面有两条反应途径,而三重态势能面仅有一条反应途径.第一个N-H断开的活化能较低,为99.96kJ/mol,活化自由能为100.86kJ/mol,在常温下就可以进行;第二个N-H键断裂所需能量高达200kJ/mol,不容易进行.在合适温度下,Ni可以活化NH3得到三重态HNiNH2,这表明Ni可以作为活化NH3分子的良好催化剂.展开更多
The energies, geometries and harmonic vibrational frequencies of 1 ： 1 5-hydroxytryptamine-water （5-HT-H20） complexes are studied at the MP2/6-311 ＋ ＋ G（d,p） level. Natural bond orbital （NBO）, quantum theory ...The energies, geometries and harmonic vibrational frequencies of 1 ： 1 5-hydroxytryptamine-water （5-HT-H20） complexes are studied at the MP2/6-311 ＋ ＋ G（d,p） level. Natural bond orbital （NBO）, quantum theory of atoms in molecules （QTAIM） analyses and the localized molecular orbital energy decomposition analysis （LMO-EDA） were performed to explore the nature of the hydrogen-bonding interactions in these complexes. Various types of hydro- gen bonds （H-bonds） are formed in these 5-HT-H20 complexes. The intermolecular C4H55HT＇＂Ow H-bond in HTW3 is strengthened due to the cooperativity, whereas no such cooperativity is found in the other 5-HT-H20 complexes. H-bond in which nitrogen atom of amino in 5-HT acted as proton donors was stronger than other H-bonds. Our researches show that the hydrogen bonding interaction plays a vital role on the relative stabilities of 5-HT-H20 complexes.展开更多
文摘The efficacy and mode of action of five chalcone-based imidazole derivatives as corrosion inhibitors of aluminium metal in gas-phase and acidic medium have been investigated herein via quantum chemical calculations. Dispersion-corrected DFT (DFT-D3) and time-dependent DFT (TD-DFT) calculations were performed at PBE0/def2-TZVP//PBEh-3c and CAM-B3LYP/def2- TZVP levels of theory, respectively. Conceptual DFT, the quantum theory of atoms-in-molecules (QTAIM) and local energy decomposition (LED) analyses have been performed. The LED analysis was performed at the coupled-cluster singles and doubles with perturbative triples (CCSD(T))/def2-SVP level of theory. Frontier molecular orbital energy gaps calculated using the TD-DFT method are found to lie in the range 3.574 - 4.444 eV, indicative of good adsorption and corrosion inhibition efficacies of the investigated molecules. The interactions between aluminium and the inhibitor molecules studied are found to be energetically favorable, owing to negative computed interaction energy values. Furthermore, QTAIM analysis revealed metal-carbon, metal-oxygen and metal-nitrogen interactions in the inhibitor-aluminium complexes, which are predominantly electrostatic in character, according to LED analysis results. Calculated proton affinities (PAs) have revealed the anticorrosion potentials of the investigated inhibitors in acidic medium, with a noticeable dependency on temperature within the range 273.15 - 343.15 K.
文摘为探索四聚吡咯配体和低价铀离子相互作用,以实验合成单层三明治结构配合物PcU~ⅥPc(Pc=酞菁)为基础,设计双层三明治型PzU^mPzU^mPz(m=Ⅲ,Ⅳ,Pz=氮杂卟啉),采用相对论密度泛函理论考察了其几何结构、异构体相对稳定性以及成键和轨道性质.得到se(staggered-eclipsed)和es(eclipsed-staggered)2种类型稳定空间异构体,并进一步优化其所有可能的电子自旋态异构体.计算结果表明,这些低价铀配合物均具有五重态基态.分子中的原子量子理论(quantum theory of atoms in molecule,QTAIM)在U—N键临界点处的电子/能量密度拓扑分析显示U—N键为弱极性共价键.四价配合物拥有4个U(5f)性质高能占据轨道,与2个U4+的5f单电子数相一致;而三价配合物有很大配体参与作用.2个铀原子和中间Pz配体质心近似成线性,这与配合物具有稳定的σ(U—U)成键轨道密切相关.
基金supported by the National Natural Science Foundation of China(92061109the Natural Science Basic Research Program of Shaanxi(2021JCW-20 and S2020-JC-WT-0001)+1 种基金the Open Project Program of Fujian Key Laboratory of Functional Marine Sensing Materials(MJUKF-FMSM202002)Guangdong Provincial Key Laboratory of Catalysis(2020B121201002).
文摘在UB3LYP/6-311++G(3df,3pd)水平下,详细研究了Ni活化NH3分子的单重态和三重态势能面,并用分子中的原子量子理论(Quantum Theory of Atom-in-Molecular,QTAIM)计算了势能面上所有驻点的性质.计算结果表明,单重态势能面有两条反应途径,而三重态势能面仅有一条反应途径.第一个N-H断开的活化能较低,为99.96kJ/mol,活化自由能为100.86kJ/mol,在常温下就可以进行;第二个N-H键断裂所需能量高达200kJ/mol,不容易进行.在合适温度下,Ni可以活化NH3得到三重态HNiNH2,这表明Ni可以作为活化NH3分子的良好催化剂.
文摘The energies, geometries and harmonic vibrational frequencies of 1 ： 1 5-hydroxytryptamine-water （5-HT-H20） complexes are studied at the MP2/6-311 ＋ ＋ G（d,p） level. Natural bond orbital （NBO）, quantum theory of atoms in molecules （QTAIM） analyses and the localized molecular orbital energy decomposition analysis （LMO-EDA） were performed to explore the nature of the hydrogen-bonding interactions in these complexes. Various types of hydro- gen bonds （H-bonds） are formed in these 5-HT-H20 complexes. The intermolecular C4H55HT＇＂Ow H-bond in HTW3 is strengthened due to the cooperativity, whereas no such cooperativity is found in the other 5-HT-H20 complexes. H-bond in which nitrogen atom of amino in 5-HT acted as proton donors was stronger than other H-bonds. Our researches show that the hydrogen bonding interaction plays a vital role on the relative stabilities of 5-HT-H20 complexes.
