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Theoretical DFT(B3LYP)/6-31+G(d) study on the prediction of the preferred interaction site of 3-methyl-4-pyrimidone with different proton donors
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作者 Mayaliwa Muzomwe Guido Maes Okuma Emile Kasende 《Natural Science》 2012年第5期286-297,共12页
Theoretical calculations were carried out using the DFT/B3LYP/6-31+G(d) methodology in an attempt to predict the preferred interaction site of a polyfunctional heterocyclic base 3-methyl-4- pyrimidone molecule with a ... Theoretical calculations were carried out using the DFT/B3LYP/6-31+G(d) methodology in an attempt to predict the preferred interaction site of a polyfunctional heterocyclic base 3-methyl-4- pyrimidone molecule with a series of proton donors of different acidic strength, i.e. water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol, pentachlorophenol, picric acid and hydrogen chlordide. Computed H-bond interaction energies (ΔEc), internuclear and intermolecular distances r(O…H) and r(O…O), infrared frequency shifts Δv(C=O) and (Δv(OH) are proved to be reliable parameters for predicting the preferred interaction site of 3-methyl-4-pyrimidone. These computational data suggest that the O-H…O=C complex is preferred with water, methanol, phenol, 1-naphtol, 2,4,5 trichlorophenol and pentachlorophenol. However, for H-bonding with stronger acids such as picric acid or hydrochloric acid, the computational data suggest that the H-bonding occurs at the N1 ring atom of 3-methyl-4-pyrimidone. In the O-H…O=C com- plex, where the H-bond at the carbonyl O-atom can be oriented “anti” (Ha) and “syn” (Hb) with respect to the N3 atom, the same computational data suggest a higher stability of the “anti-O” compared to the “syn-O” orientation. 展开更多
关键词 3-Methyl-4-pyrimidone dft/B3lyp CALCULATION Proton-Donor CAPABILITY
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Theoretical Study of Benzothiazole and Its Derivatives: Molecular Structure, Spectroscopic Properties, NBO, MEP and TD-DFT Analyses
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作者 Konaté Abdoulaye Bédé Affoué Lucie +2 位作者 Ouattara Lamoussa Koné Soleymane Bamba Kafoumba 《Journal of Materials Science and Chemical Engineering》 2024年第3期31-50,共20页
Benzothiazole (BTH) and its derivatives are organic molecules with biologic actions. Because of their many applications, they are produced on a massive scale and used in a number of environmental compartments. Their d... Benzothiazole (BTH) and its derivatives are organic molecules with biologic actions. Because of their many applications, they are produced on a massive scale and used in a number of environmental compartments. Their discharge into water produces environmental problems, exposing our environment to public health problems. A solution that can contribute to their deterioration is becoming a necessity. For this reason, a conceptual analysis of the reactivity of benzothiazole and four of its compounds was undertaken in order to investigate certain aspects of their biodegradability. A theoretical investigations of the compounds studied were conducted in the gas and water phases with the most widely used density functional theory method, Becke-3-Parameter-Lee-Yang-Parr (B3LYP) with 6-31G+ (d, p) basis. Reactivity study calculated global indices of reactivity revealed that 2-SCH3_BTH is the most reactive. Dipole moment values analysis reveals that 2-NH2_BTH is the most soluble in water, while the lipophilicity shows that 2-NH2_BTH is the most hydrophilic compound. Thermodynamic parameters values reflect that reactions are respectively exothermic and spontaneous. By analyzing an Electrostatic Molecular Potential (EMP) map, researchers can pinpoint reactive sites on a molecule and anticipate its reactivity. This assessment is further enhanced by incorporating global and local reactivity descriptors. Additionally, an exploration of frontier molecular orbitals offers valuable insights into the molecule’s charge transfer characteristics. Moreover, a combined examination of internal and external molecular interactions unveils hyperconjugative interactions arising from charge delocalization, as elucidated through natural bond orbital (NBO) analysis. 展开更多
关键词 BENZOTHIAZOLE REACTIVITY dft/B3lyp Stability TD-dft
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HO_3、HO_3^+、HO_3^-光谱和结构的MP2和DFT理论研究 被引量:1
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作者 裴克梅 张先燚 +1 位作者 孔祥蕾 李海洋 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2002年第4期263-268,共6页
用B3LYP和MP2量子化学理论 ,详细地计算了HO3 、HO+ 3 、HO-3 可能的平衡构型、能量和光谱参数 ,分析了它们可能的解离通道和稳定性 .还分析了HO3 的电离势 (IE)及电子亲和势 (Ea) ,讨论了HO3 、HO3 -自由基的光电子能谱的特征 ,及用光... 用B3LYP和MP2量子化学理论 ,详细地计算了HO3 、HO+ 3 、HO-3 可能的平衡构型、能量和光谱参数 ,分析了它们可能的解离通道和稳定性 .还分析了HO3 的电离势 (IE)及电子亲和势 (Ea) ,讨论了HO3 、HO3 -自由基的光电子能谱的特征 ,及用光电子能谱去探测HO3 展开更多
关键词 光谱 MP2 dft 理论研究 HO3自由基 B3lyp 平衡结构 光电子能谱 量子化学 氢氧自由基
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A DFT Study for NH_3 Adsorption on the GaN (0001) Surface 被引量:1
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作者 吕乃霞 徐艺军 +2 位作者 陈文凯 章永凡 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2004年第8期845-849,共5页
The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored ... The ammonia adsorption on the GaN (0001) surface has been investigated by using DFT/B3LYP method combined with the cluster model approach. The dissociative adsorp- tion of NH2 and H is found thermodynamically favored relative to the molecular NH3 adsorption by decreasing the total energy of 0.95 eV. The adsorption geometries of the molecular and dis- sociative NH3 are given in detail, among which the molecular NH3 bonds to the surface Ga with its lone electronic pair, and the N atom of NH2 adspecies forms the four-fold coordinated N by bridging two surface Ga atoms. 展开更多
关键词 GAN CHEMISORPTION NH3 cluster model dft/B3lyp
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CF3和CH3取代吡啶吡唑硼配合物的结构和吸收光谱的理论研究 被引量:4
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作者 杨彦杰 潘秀梅 +1 位作者 刘丽丽 崔琳琳 《东北师大学报(自然科学版)》 CAS CSCD 北大核心 2008年第4期101-104,共4页
采用密度泛函理论DFT/B3LYP在6-31G水平上研究了CH3和CF3取代吡啶吡唑硼配合物的几何和电子结构,在基态平衡构型的基础上通过含时密度泛函理论TD-DFT计算了其光谱性质.结果表明:氟代甲基吡啶甲基吡唑硼配合物(2b′)的配位键略强于甲基... 采用密度泛函理论DFT/B3LYP在6-31G水平上研究了CH3和CF3取代吡啶吡唑硼配合物的几何和电子结构,在基态平衡构型的基础上通过含时密度泛函理论TD-DFT计算了其光谱性质.结果表明:氟代甲基吡啶甲基吡唑硼配合物(2b′)的配位键略强于甲基吡啶氟代甲基吡唑硼配合物(2b);二者的中心B原子对分子的结构不但起支撑稳定作用,还可以作为电子桥传输电子;当取代基交换位置时,苯环和吡唑环都可以作为空穴传输基团,电子传输基团仍为吡啶环,配合物的主要跃迁都属于配体内部的π→π*跃迁类型. 展开更多
关键词 硼配合物 dft/B3lyp 吸收光谱 TD-dft
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二维电荷转移型水杨醛缩乙二胺类双席夫碱及其Zn(Ⅱ)配合物的电子光谱及非线性光学性质的DFT理论研究 被引量:12
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作者 颜力楷 苏忠民 +3 位作者 阚玉和 仇永清 朱东霞 王悦 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2003年第10期1876-1879,共4页
用密度泛函理论 ( DFT) B3 LYP方法 ,在 6-3 1 G( d)基组水平上优化水杨醛缩乙二胺类双席夫碱化合物及其 Zn( )配合物的几何结构 .在稳定构型基础上 ,引入外电场 ,运用有限场 ( FF)方法 ,计算标题化合物体系的非线性光学 ( NLO)系数 ,... 用密度泛函理论 ( DFT) B3 LYP方法 ,在 6-3 1 G( d)基组水平上优化水杨醛缩乙二胺类双席夫碱化合物及其 Zn( )配合物的几何结构 .在稳定构型基础上 ,引入外电场 ,运用有限场 ( FF)方法 ,计算标题化合物体系的非线性光学 ( NLO)系数 ,并与其独立的对称分子片结构进行比较 .同时用含时密度泛函理论 ( TD-DFT)计算各体系的电子光谱 .结果表明 ,两个单席夫碱分子片结合为双席夫碱时 ,二阶及三阶 NLO系数明显增大 ,且 γ比 β显著 .双键桥连 Zn配合物 1 a的 β,γ值均小于相应配体 ,而单键桥连 Zn配合物 2 a的 β和γ值大于相应配体 ,说明金属 Zn在完全共轭和局域共轭体系中所起的作用不同 . 展开更多
关键词 二维电荷转移 水杨醛缩乙二胺类双席夫碱 Zn(Ⅱ)配合物 电子光谱 非线性光学性质 dft 含时密度泛函理论 B3lyp/FF方法
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3-硝基-1,2,4-三唑-5-酮与NH_3及H_2O分子间相互作用的理论研究 被引量:20
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作者 方国勇 徐丽娜 +1 位作者 肖鹤鸣 居学海 《化学学报》 SCIE CAS CSCD 北大核心 2005年第12期1055-1061,i002,共8页
在DFT-B3LYP/6-311++G**水平上,求得3-硝基-1,2,4-三唑-5-酮(NTO)/NH3和NTO/H2O两种超分子体系势能面上5种全优化构型.经基组叠加误差(BSSE)和零点能(ZPE)校正,求得NTO与NH3和H2O的分子间最大相互作用能依次为-37.58和-30.14kJ/mol,表明... 在DFT-B3LYP/6-311++G**水平上,求得3-硝基-1,2,4-三唑-5-酮(NTO)/NH3和NTO/H2O两种超分子体系势能面上5种全优化构型.经基组叠加误差(BSSE)和零点能(ZPE)校正,求得NTO与NH3和H2O的分子间最大相互作用能依次为-37.58和-30.14kJ/mol,表明NTO与NH3的分子间相互作用强于与H2O的作用.超分子体系中电子均由NH3或H2O向NTO转移,相互作用能主要由强氢键所贡献,由自然键轨道分析揭示了相互作用的本质.对优化构型进行振动分析,并基于统计热力学求得200.0~800.0K温度范围从单体形成超分子的热力学性质变化.发现由NTO和NH3形成超分子II和III在常温下可自发进行;而NTO和H2O只在低温下才能自发形成IV,V和VI超分子. 展开更多
关键词 分子间相互作用 H2O NH3 理论研究 硝基 三唑 自然键轨道分析 超分子体系 相互作用能 优化构型 NTO B3lyp 统计热力学 振动分析 性质变化 温度范围 dft 零点能 势能面 mol 基组 电子 氢键 低温
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反式共轭类碳烯CH_2CH—CHC∶LiF氢迁移反应的DFT研究 被引量:5
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作者 李文佐 宫宝安 程建波 《分子科学学报》 CAS CSCD 2007年第1期28-32,共5页
应用密度泛函理论DFT方法,在B3LYP/6-31G*水平上研究了反式共轭类碳烯CH2CH—CHC∶LiF的氢迁移反应.计算优化了反应过程中的所有反应物、中间体、过渡态和产物的几何构型,通过频率振动分析确定中间体和过渡态.结果表明,在β位上的H... 应用密度泛函理论DFT方法,在B3LYP/6-31G*水平上研究了反式共轭类碳烯CH2CH—CHC∶LiF的氢迁移反应.计算优化了反应过程中的所有反应物、中间体、过渡态和产物的几何构型,通过频率振动分析确定中间体和过渡态.结果表明,在β位上的H原子迁移过程中,经历一个带有三元环结构的中间体和两个带有三元环结构的过渡态.第一步反应势垒较大. 展开更多
关键词 反式共轭类碳烯CH2=CH-CH=C:LiF dft B3lyp 氢迁移反应
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Al_mN(m=2~9)团簇结构与稳定性的DFT研究 被引量:3
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作者 马文瑾 武海顺 《物理化学学报》 SCIE CAS CSCD 北大核心 2003年第10期927-932,共6页
用密度泛涵理论(DFT)的B3LYP方法在6-31G水平上对AlmN(m=2~9)团簇的几何构型、电子结构、振动频率等性质进行了理论研究.给出了以Alm团簇作为设计AlmN类结构的母体,考虑在不同位置上结合N原子的结构,可以较快找到AlmN类团簇基态结构的... 用密度泛涵理论(DFT)的B3LYP方法在6-31G水平上对AlmN(m=2~9)团簇的几何构型、电子结构、振动频率等性质进行了理论研究.给出了以Alm团簇作为设计AlmN类结构的母体,考虑在不同位置上结合N原子的结构,可以较快找到AlmN类团簇基态结构的一种方法.通过对基态结构的几何参数分析发现,m<4的结构只存在Al-N键;m≥4的结构,Al-N键和Al-Al键共存.对基态结构的绝热电离能讨论结果表明,只存在Al-N键的Al2N和Al3N团簇较稳定. 展开更多
关键词 AlmN团簇 结构 稳定性 dft 密度泛涵理论 B3lyp方法
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DFT和热力学研究氢键协同效应及对关联~1H NMR的影响 被引量:7
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作者 蓝蓉 李浩然 韩世钧 《化学学报》 SCIE CAS CSCD 北大核心 2005年第14期1288-1292,i002,共6页
用DFT方法在B3LYP/6-311++G(d,p)水平下研究了甲醇线性和环状分子簇.对于不同大小的分子簇之间定义了协同因子.计算得到的协同因子可以验证氢键的强协同效应,环状分子簇之间的协同效应远远大于线性分子簇.做为理论验证和比较,热力学模... 用DFT方法在B3LYP/6-311++G(d,p)水平下研究了甲醇线性和环状分子簇.对于不同大小的分子簇之间定义了协同因子.计算得到的协同因子可以验证氢键的强协同效应,环状分子簇之间的协同效应远远大于线性分子簇.做为理论验证和比较,热力学模型分别采用含氢键缔合的格子流体状态方程(LFHB),以及含氢键协同效应的LFHB,关联醇-惰性体系的1H核磁共振化学位移.考虑协同效应的关联结果优于原始的LFHB.比较量子化学计算的和热力学模型中采用的协同因子,认为甲醇和乙醇在溶液中更可能大部分以线性缔合形式存在. 展开更多
关键词 协同效应 ^1H 力学研究 对关联 NMR 热力学模型 量子化学计算 B3lyp dft方法 分子簇 理论验证 状态方程 氢键缔合 化学位移 核磁共振 因子 线性 环状 甲醇 流体 格子 溶液
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H和CH_3NO_2分子中C,N,O原子作用反应机理的研究 被引量:1
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作者 冀永强 孙秀良 郭玉华 《宁夏大学学报(自然科学版)》 CAS 北大核心 2006年第1期43-47,共5页
采用DFT(B3LYP)方法,在6-311G**,6-311++G**,cc-pvtz基组水平上,优化了H自由基分别进攻CH3NO2上的C,N,O原子反应的各驻点的几何结构,研究了反应体系中各反应沿极小能量途径反应分子几何构型的变化,根据计算得出的各反应的位垒和反应热... 采用DFT(B3LYP)方法,在6-311G**,6-311++G**,cc-pvtz基组水平上,优化了H自由基分别进攻CH3NO2上的C,N,O原子反应的各驻点的几何结构,研究了反应体系中各反应沿极小能量途径反应分子几何构型的变化,根据计算得出的各反应的位垒和反应热力学参数指出了反应位垒对反应的影响. 展开更多
关键词 CH3NO2 H自由基 反应机理 从头算dft(B3lyp)法
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不饱和类碳烯H_2C═CLiBr的DFT研究 被引量:5
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作者 刘奉岭 《分子科学学报》 CAS CSCD 2002年第3期151-155,共5页
采用量子化学计算方法 ,在B3LYP/ 6-3 1 1G 水平上全优化得到了不饱和类碳烯H2 CCLiBr的平衡结构 .结果表明 ,不饱和类碳烯H2 CCLiBr只有两种平衡结构 .对这两种平衡结构之间相互转化的过渡态进行计算 ,求得了转化势垒 .根据计算得到的... 采用量子化学计算方法 ,在B3LYP/ 6-3 1 1G 水平上全优化得到了不饱和类碳烯H2 CCLiBr的平衡结构 .结果表明 ,不饱和类碳烯H2 CCLiBr只有两种平衡结构 .对这两种平衡结构之间相互转化的过渡态进行计算 ,求得了转化势垒 .根据计算得到的微观性质 ,采用统计热力学方法 ,研究了两种平衡结构之间相互转化的热力学性质 ,进而讨论了两种平衡结构在不同温度下的稳定性问题 .在计算得到振动频率及强度的基础上 ,模拟了稳定平衡结构的红外光谱图 . 展开更多
关键词 dft 不饱和类碳烯 H2C=CLiBr ab INITIO B3lyp/6-311G^* 热力学函数 过渡态 量子化学 平衡结构
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CH_3NO_2+O[~3P]→CH_2NO_2+OH反应途径和速率常数的研究
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作者 冀永强 郭玉华 《宁夏大学学报(自然科学版)》 CAS 北大核心 2005年第1期48-52,共5页
采用DFT(B3LYP)从头算法,在6 311G**和cc pvtz基组水平上,优化了CH3NO2+O[3P]→CH2NO2+OH反应的反应物、过渡态和产物的几何结构,结果表明,基组选择对驻点的几何构型影响很小.由B3LYP/cc pvtz计算所得的反应位垒为24.52 kJ/mol,比实验值... 采用DFT(B3LYP)从头算法,在6 311G**和cc pvtz基组水平上,优化了CH3NO2+O[3P]→CH2NO2+OH反应的反应物、过渡态和产物的几何结构,结果表明,基组选择对驻点的几何构型影响很小.由B3LYP/cc pvtz计算所得的反应位垒为24.52 kJ/mol,比实验值22.38 kJ/mol大2.14 kJ/mol.沿内禀反应坐标(IRC)的分析指出,C—H键断裂和H—O键生成是以协同方式进行的,且在反应途径上存在一个引导反应进行的振动模式,这一振动模式引导反应进行的区间为S=-0.35~0.85(amu)1/2Bohr;在1 300~2 100 K范围内运用改进的变分过渡态理论(ICVT)计算出的该反应速率常数与实验结果一致. 展开更多
关键词 CH3NO2 三线态氧 dft(B3lyp)从头算法 速率常数 变分过渡态理论
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4种C_(12)H_(12)多面体烷振动频率及生成焓的DFT研究
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作者 刘奉岭 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2003年第1期97-102,共6页
采用密度泛函方法,在B3LYP/D95*水平上对4种C12H12多面体分子的构型进行了全优化,计算了其振动频率及红外吸收强度,并模拟了它们的红外光谱图。采用统计热力学方法,在200~600K的温度范围内,分别计算了立方烷生成这4种C12H12多面体分子... 采用密度泛函方法,在B3LYP/D95*水平上对4种C12H12多面体分子的构型进行了全优化,计算了其振动频率及红外吸收强度,并模拟了它们的红外光谱图。采用统计热力学方法,在200~600K的温度范围内,分别计算了立方烷生成这4种C12H12多面体分子的热力学函数。由计算得到的自由能得知,这些分子都比立方烷稳定,因此从热力学角度来说,既然立方烷能够合成,这4种C12H12多面体分子也应该能够合成出来。根据计算得到的热力学函数及立方烷的生成焓,求出了这4种C12H12多面体分子的生成焓。 展开更多
关键词 C12H12 多面体烷烃 生成焓 dft 多面体分子 B3lyp/D95 振动频率 热力学函数 密度泛函
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Alq3及其衍生物电子传输性质的理论研究
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作者 董士红 尹世伟 王文亮 《陕西师范大学学报(自然科学版)》 CAS CSCD 北大核心 2008年第6期58-62,共5页
采用密度泛函理论(DFT)B3LYP/6-31G方法对三-(8-羟基喹啉)铝(Alq3)及3种二氟取代衍生物进行了计算研究,分析比较了4种配合物的前线分子轨道组成、轨道能级、电离能、电子亲和势及重整能等性质的同异.结果表明,各配合物的电子跃迁主要发... 采用密度泛函理论(DFT)B3LYP/6-31G方法对三-(8-羟基喹啉)铝(Alq3)及3种二氟取代衍生物进行了计算研究,分析比较了4种配合物的前线分子轨道组成、轨道能级、电离能、电子亲和势及重整能等性质的同异.结果表明,各配合物的电子跃迁主要发生在不同配体之间的π→π*跃迁.苯酚环上6,7-二氟取代使电子跃迁能力降低,而5,6和5,7-二氟取代使电子跃迁能力提高.二氟取代均可较显著地使得最低空轨道的能级降低,电子亲和势升高,有利于电子注入.此外,5,7-二氟取代后配合物的电子重整能和空穴重整能显著增大,材料稳定性降低.因此,综合比较各因素的影响,Alq3在6,7位置吸电子基团取代有望成为优良的电子材料. 展开更多
关键词 三-(8-羟基喹啉)铝 二氟取代衍生物 电子传输 重整能 (dft)B3lyp/6-31G
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DFT Thermodynamic Research of the Pyrolysis Mechanism of the Carbon Matrix PrecursorTol uene for Carbon Material 被引量:2
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作者 WANG Hui, YANG Hai-feng, RAN Xin-quan WEN Zheng-yi and SHI Qi-zhen (Chemistry Department, Modern Physics Institute and, Key Laboratory of Physics Inorganic Chemistry of Shan-Xi Province, Northwest University, Xi’an 710069, P. R. China) 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2001年第2期219-225,共7页
Based on the experiments, the standard enthalpy△H■of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G *(based on semi-empirical method UA... Based on the experiments, the standard enthalpy△H■of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G *(based on semi-empirical method UAM1 and ab initio method UHF/3-21G*). The com- putation results with UB3LYP/3-21G* coincide with the experimental values well. Then, the mechanism for all types of the pyrolysis reactions of toluene was studied by UB3LYP/3-21G * The geometries of the reactant and the product radicals were optimized, meanwhile, the standard thermodynamic parameters of the pyrolysis reaction at different temperatures (298, 773, 843, 963 and 1 073 K) were calculated. The thermodynamic computation result shows that when the pyrolysis temperature of toluene is lower than 963 K, the reaction path supported by thermody- namics is that the C-H bond of the methyl on the benzene ring breaks and bitoluene form, while the temperature increases (about 1 073 K), the thermodynamic calculation result turns to support the reaction path producing phenyl radicals and methyl radicals. This mechanism is in accord with the experiments. 展开更多
关键词 Carbon/carbon composites TOLUENE Pyrolysis mechanism ub3lyp/3-21G
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Synthesis,Crystal Structure and Spectroscopic Properties of 1,2-Benzothiazine Derivatives:An Experimental and DFT Study 被引量:1
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作者 MUHAMMAD Nadeem Arshad TARIQ Mahmood +7 位作者 ATHER Faroque Khan MUHAMMAD Zia-Ur-Rehman ABDULLAH M.Asiri ISLAM Ullah Khan RIFFAT-Un-Nisa KHURSHID Ayub AZAM Mukhtar MUHAMMAD Tariq Saeed 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第1期15-25,共11页
1,2-Benzothiazine derivatives methyl 3-methoxy-4-oxo-3,4-dihydro-2H-benzo[e] [1,2]thiazine-3-carboxylate 1,1-dioxide(1) and methyl 2-ethyl-3-hydroxy-4-oxo-3,4-dihydro-2Hbenzo[e][1,2]thiazine-3-carboxylate 1,1-dioxid... 1,2-Benzothiazine derivatives methyl 3-methoxy-4-oxo-3,4-dihydro-2H-benzo[e] [1,2]thiazine-3-carboxylate 1,1-dioxide(1) and methyl 2-ethyl-3-hydroxy-4-oxo-3,4-dihydro-2Hbenzo[e][1,2]thiazine-3-carboxylate 1,1-dioxide(2) were synthesized, and characterized by spectroscopic techniques; 1H-NMR and infrared(IR) spectroscopy. Crystals of 1 and 2 were grown by slow evaporation of methanol and ethyl acetate, respectively and their crystal structures were investigated by single-crystal X-ray diffraction analysis. Geometric properties were calculated by the B3 LYP method of density functional theory(DFT) at the 6-31G+(d) basis set to compare with the experimental data. Simulated properties were found in strong agreement with the experimental ones. Intermolecular forces have also been modeled in order to investigate the strength of packing and strong hydrogen bonding was observed in both compounds 1 and 2. Electronic properties such as Ionization Potential(IP), Electron Affinities(EA) and coefficients of the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) of com- pounds 1 and 2 were simulated for the first time. 展开更多
关键词 1 2-benzothiazine B3lyp/6-31+G (d) density functional theory dft HUMO-LUMO crystal structures
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DFT studies on the SCR reaction mechanism of nitrogen monoxide with propylene catalyzed by copper oxide
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作者 田英 许晶 赵景祥 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第3期389-391,共3页
The SCR reaction mechanism of NO with C3H6catalyzed by CuO was studied by the method of Density Functional Theory(DFT)at the B3LYP/LanL2DZ levels.The optimized geometries of the stationary points on the potential surf... The SCR reaction mechanism of NO with C3H6catalyzed by CuO was studied by the method of Density Functional Theory(DFT)at the B3LYP/LanL2DZ levels.The optimized geometries of the stationary points on the potential surface were obtained and the transition state was confirmed by IRC and vibration analysis.The activation energy was calculated being 34.26 kJ/mol.It was shown that propylene reacted firstly with Cu forming intermediate,and then nitrogen monoxide immediately reacted with the intermediate to be reduced.It was proved to be a direct interaction mechanism. 展开更多
关键词 catalyst CuO PROPYLENE nitrogen monoxide immediate reaction mechanism dft/B3 lyp calculation
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Computational Study of the Cyclization of 5-Hexenyl, 3-Oxa-5-Hexenyl and 4-Oxa-5-Hexenyl Radicals
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作者 Albert R. Matlin Matthew C. Leyden 《International Journal of Organic Chemistry》 2013年第3期169-175,共7页
The intramolecular cyclization of 5-hexenyl radicals continues to be an important synthetic method for the construction of five-membered rings. The synthetic utility arises from the high degree of regioselectivity to ... The intramolecular cyclization of 5-hexenyl radicals continues to be an important synthetic method for the construction of five-membered rings. The synthetic utility arises from the high degree of regioselectivity to give predominantly cyclopentyl products in high yield under mild conditions. Recently we reported product cyclization studies on 4-oxa perturbed 5-hexenyl radical. In this paper, we report our results from a computational study (UB3LYP and UCCSD (T)) of the cyclization of a series of 5-hexenyl and 3-and 4-oxa-5-hexenyl radicals. Three highly conserved cyclization tran-sitions states (exo-chair, exo-boat and endo-chair) were located for 10 acyclic radicals. Activation energies were calcu-lated for the three modes of cyclization for each radical. Calculated values for the exo/endo cyclization ratios had a high level of agreement with experiment and predictions were offered for two cases that have not been experimentally tested. The increased percentage of exo-cyclization with 3-and 4-oxa substitution is the result of an increase in the energy dif-ference between the exo-and endo-chair transition states compared to the hydrocarbon systems. The decreased rate of cyclization of the 4-oxa compounds is primarily due to the stabilization of the initial acyclic radical by the vinyl ether linkage. The increase in the rate of cyclization with 3-methyl substitution is due to the increased conformational energy of the starting acyclic radical. 展开更多
关键词 RADICAL CYCLIZATIONS Activation ENERGIES ub3lyp UCCSD (T)
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以杂环做端基的高自旋双自由基分子的理论研究 被引量:6
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作者 储德清 王立敏 +1 位作者 张景萍 王荣顺 《东北师大学报(自然科学版)》 CAS CSCD 北大核心 2007年第1期81-83,共3页
研究了以杂环做端基的高自旋分子对自旋稳定性的影响,用UB3LYP/6-31G*方法计算得到分子构型与自旋交换的性质.结果表明:以—.N—O做自旋中心,苯做耦合单元,吡啶、嘧啶、三嗪为端基的分子,—.N—O自由基的体系非常稳定性,同时分子中三重... 研究了以杂环做端基的高自旋分子对自旋稳定性的影响,用UB3LYP/6-31G*方法计算得到分子构型与自旋交换的性质.结果表明:以—.N—O做自旋中心,苯做耦合单元,吡啶、嘧啶、三嗪为端基的分子,—.N—O自由基的体系非常稳定性,同时分子中三重态以三嗪为端基的稳定性最稳定,以嘧啶为端基的稳定性最低;以—.N—S,—.N—O,—.N—NH做自旋中心,苯为耦合单元,吡啶为端基的分子,分子中三重态稳定以—.N—S为自旋中心的最稳定,以—.C—O为自旋中心的稳定性最低. 展开更多
关键词 杂环 端基 双自由基 ub3lyp
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