C6H6和SO3相互作用的理论研究（英文）

采用B3LYP和MP2方法在6-31G*、6-31+G*和6-311+G**基组下对C6H6…SO3复合物体系的4种可能结构进行自由优化,得3种。在考虑基组重叠误差校正基础上,得结合能,并用自然键轨道分析方法讨论其相互作用。结果表明,用B3LYP/6-31G*计算3种复合物的结合能分别为-17.75, -18.33, -18.80 kJ/mol,且C6H6和SO3结合时电子从苯环向SO3转移,形成电荷转移复合物,它们之间的作用包含π-p作用方式。     

乙硼烷与HX(X=F,CI,Br)之间的二氢键

对乙硼烷与HX形成的二氧键复合物的结构特征及本质进行探讨.在MP2/6-311++G(3d,3p)水平优化、频率验证所得复合物的分子结构,通过分子间距离及H…H间的拓扑参数,确认B2H6与卤化氢形成二氢键复合物.在MP2/6-311++G(3d,3p)水平校正BSSE后的结合能在-7.0124 kJ/mol～-4.6652 kJ/mol之间.用对称匹配微扰理论(SAPT)分解结合能,结果静电作用是B2H6与HX形成二氢键复合物的必要条件和重要的推动力,但又并不完全是静电所致,总之,静电、诱导、色散等作用对二氧键的形成都是重要的.     

密度泛函理论和从头计算法研究环戊二烯衍生物气态酸度及其取代基效应

用B3LYP／6-311G(2df,p)／／B3LYP／631 G*和MP2／6-311G(d,p)／／B3LYP／6-31 G*方法准确地预测了9个系列的环戊二烯衍生物(R=CN,CF3,CHO,C283,F,SiH3,H,CH3,OH,NH2)的C-H键的酸度。环戊二烯衍生物气态酸度的范围从284.9 kcal／mol (化合物5a)到357.24kcal／mol(化合物7j),分析取代基的电性、数量以及位置的影响得到了9个QSAR方程。这些数据有助于我们设计以及合成一些有机酸,并有助于深刻理解相关反应中环戊二烯衍生物的性质。     

丙烯酸正丁酯聚合的Diels-Alder反应机理理论研究

本文从理论上对丙烯酸正丁酯(nBA)自引发聚合的Diels-Alder反应机理进行了研究.利用DFT方法在UB3LYP/6-31G*水平上对反应的最低能量路径进行了计算,各驻点能量分别采用MP2/6-311G**和B3LYP/6-311 G(3df;2p)进一步精确计算.结构表明:此Diels-Alder反应仅包括一种途径,即路径(I),另一条途径在热力学不支持.     

十二胺捕收剂溶剂化效应及其水相氢键超分子作用的密度泛函研究

采用密度泛函方法研究了十二胺在气相、苯、乙酸、乙醇及水中的分子构型、电荷分布以及前线轨道。首先采用B3LYP/6-31G(d,p)及B3 LYP/6-311++G(d,p)进行优化,采用自洽反应理论(SCRF)的极化连续介质模型(PCM)进行不同溶剂条件下的优化并进行自然键轨道(NBO)分析。结果表明,对比气相条件下,十二胺分子的几何构型发生了微弱变化,这种变化随着溶剂介电常数的增加长程稳定性增强,溶剂化效应使前线轨道中HOMO趋于比LUMO更稳定,NBO分析表明溶剂化能主要来源于LP(1)N_(38)→π~*C_(32)-C_(33)。随着溶剂介电常数的增加,十二胺分子采用B3 LYP/6-31+G(d,p)的△E_(HOMO)-E_(LUMO)由气相-0.23773 a.u至水相中-0.25120 a.u,溶剂化能-13.36 kcal/mol,采用B3 LYP/6-311++G(d,p)的△E_(HOMO)-E_(LUMO)由气相-0.22755 a.u至水相中-0.24004 a.u,溶剂化能-13.02 kcal/mol,溶剂化能趋于稳定,表明十二胺分子的溶剂化效应采用B3 LYP/6-31+G(d,p)构型趋于稳定。采用B3LYP/6-31+G(d,p)对十二胺与水分子氢键超分子结构进行了研究,利用分子静电势(MEP)进行氢键及反应活性位分析,结果表明氢键作用是引起十二胺分子结构和性质变化的主要原因。研究结果对十二胺捕收剂在溶剂条件下对矿物的浮选机理认识具有一定的理论意义。     

苯甲基阴离子复合物结构与性质的理论研究

用G98程序在B3LYP和MP2方法上和理论上计算苯…甲基阴离子复合物以预测其构型,得4种.在考虑基组重叠误差校正基础上,得结合能,并用自然键轨道分析法讨论其相互作用.结果表明,甲基阴离子中C13与苯中的一个C原子直接相连的构型比较稳定,其结合能为-108.45 kJ/mol(B3LYP/6-31+G*)、-154.1 kJ/mol(MP2(FC)/6-311++G**).其余的构型靠碳的孤对电子与C-Hσ反键轨道作用而形成,且稳定性较差.     

5-氟尿嘧啶…NO分子复合物的结构与性质

用密度泛函理论,在BL3YP/6-311++G**基组水平上研究5-氟尿嘧啶…NO复合物体系,用更大基组(6-311+G(2df,p)和aug-cc-pVDZ)进行单点能的计算,发现5个能量极小的复合物。同时,使用自然键轨道(NBO)法和分子中的原子(AIM)法对5-氟尿嘧啶和NO分子间的作用本质进行了分析。结果显示,5-氟尿嘧啶和NO的结合方式是NO的N、O原子与5-氟尿嘧啶的N-H键形成氢键,或O原子与5-氟尿嘧啶分子间通过弱π键结合在一起。最稳定复合物的结合能为-7.86 kJ/mol。N原子与5-氟尿嘧啶的结合更有优势,N结合的复合物中,NO键长缩短,伸缩振动频率蓝移,而O结合的复合物中,NO键长伸长,伸缩振动频率发生红移。     

论(Cl_2BN_3)_n(n=1-4)簇合物

用密度泛函论B3LYP/6-311+G*法,计算(C1_2BN_3)_n(n=1-4)簇合物的结构和性质.发现,多聚体(C1_2BN_3)_n(n=2-4)的优化构型原来是由不同子体系的叠氮基α-N和B原子相连而形成的环状结构。几何参数的比较分析还发现N_α-B、N_α-N_β、N_β-N_Υ和B-Cl的键长与聚合度密切相关,环状构型中B-N_α-B键角总比N_α-B-N_α大。同时计算所有优化构型的振动频率,将其IR谱归类.通过热力学计算,发现簇合物的稳定性为3A>3B;4A>4B.由焓变可知,从单体形成二聚体于热力学不利,而形成最稳定三聚体和四聚体的温度分别达800K和500K仍是有利的.     

CH3S与CH2SH自由基反应的密度泛函理论研究

用量子化学从头算和密度泛函理论(DFT)对CH3S与CH2SH自由基反应进行了研究。在B3LYP/6-311+G(d,p)水平上优化了反应通道各驻点物种(反应物、中间体、过渡态和产物)的几何构型,用内禀反应坐标(IRC)计算和频率分析的方法对过渡态结构及连接性进行了验证。在QCISD(T)/6-311++G(d,p)水平上计算了各物种的单点能,并对总能量进行了零点能校正。研究结果表明,CH3S与CH2SH反应为多通道反应,有3条可能的反应通道。反应物首先通过C-S键相互作用形成链状碳-硫偶合中间体IM1,再经过裂解和脱氢气机理生成主要产物P1(CH3SH+CH2S)和次要产物P2和P3。根据势能面分析,所有反应均为吸热反应。相对于CH3S与CH2SH,各产物能量分别为(-175.2,335.5和331.5)kJ.mol-1。     

脂肪胺类化合物脂水分配系数的QSPR研究(英文)

用16种脂肪胺类化合物HF/6-31G**,HF/6-311G**,DFT-B3LYP/6-31G**和DFT-B3LYP/6.311G**全优化计算结构参数:分子最高占用和最低空轨道能(EHOMO和ELUMO),分子次最高占用和次最低空轨道能(ENHOMO和ENLUMO),分子总能量(ET),氢原子所带的最高正电荷(qH+),最负原子的静电荷(q-),分子偶极矩(μ)和分子体积(V),对它们的脂水分配系数(lgKOW)分别进行定量构效关系(QSPR)研究.结果表明:脂肪胺的lgK与分子最低空轨道能(ELUMO),分子的总能量(ET)和分子偶极距(μ)的相关性较好,成功地建立了lgKOW的QSPR方程.特别是基于B3LYP/6-311G**基组建立的方程具有更好的[[预]能力,并通过VIF值和t值对其稳健性进行了检验,结果良好.     

Microstructural,dielectric and piezoelectric properties of low-temperature sintering Pb(Co1/2W1/2)O3–Pb(Mn1/2Nb2/3)O3–Pb(Zr,Ti)O3 ceramics with the addition of Li2CO3 and Bi2O3

In this study, in order to develop the low-temperature sintering ceramics for multilayer piezoelectric devices, Pb(Co_1/2W_1/2)O₃–Pb(Mn_1/2Nb_2/3)O₃–Pb(Zr,Ti)O₃ (PCW–PMN–PZT) ceramics doped with Li₂CO₃, Bi₂O₃ and CuO as sintering aids were manufactured, and their microstructural, dielectric and piezoelectric properties were investigated. When the only CuO was added, specimens could not be sintered below 980 °C. However, when Li₂CO₃ and Bi₂O₃ with CuO were simultaneously added to the basic composition ceramics, specimens could be sintered below 980 °C. The addition of Li₂CO₃ and Bi₂O₃ were proved to lower sintering temperature of piezoelectric ceramics due to the effect of Li₂CO₃–Bi₂O₃ liquid phase. Piezoelectric properties of Li₂CO₃ and Bi₂O₃ added specimens showed higher values than those of the only CuO added specimens. At 0.2 wt% Li₂CO₃ and 0.3 wt% Bi₂O₃ added specimen sintered at 920 °C, the dielectric constant (ɛ_r) of 1457, electromechanical coupling factor (k_p) of 0.56 and mechanical quality factor (Q_m) of 1000 were shown, respectively. It is considered that these values are suitable for piezoelectric device application such as multilayer piezoelectric transformer and ultrasonic vibrator with pure Ag internal electrode.     

配合物{Cu[PHBA]2(H2O)3}(H2O)3的水热合成、晶体结构、电化学分析及量化计算

在甲醇和水的混合溶剂中通过水热反应,以对羟基苯甲酸和4,4′-联吡啶为配体合成了配合物{Cu[PHBA]_2(H_2O)_3} (H_2O)_3,并测定了配合物的晶体结构,该晶体属三斜晶系,空间群c2(1),晶胞参数为:a=2.4428(5)nm,b=1.14476(17)nm,c=0.72516(11)nm,α=β=γ=90.00°,V=2.0278(6)nm~3,Dc=1.578g/cm~3,Z=4,F(000)=1004。最终偏离因子R_1= 0.0304,wR_2=0.0796。配合物中Cu(Ⅱ)离子与2个对羟基苯甲酸的2个羧基O原子及3个水分子中的3个氧原子配位,形成三角双锥结构,铜位于结构中心。结合晶体结构对配合物进行了电化学性质分析和量子化学计算。     

化合物Mn(C6H4O2N)2(H2O)4的水热合成、晶体结构及量子化学计算

以异烟酸和1,10-邻菲啰啉为配体通过水热反应合成了化学合物Mn(C6H4O2N)2(H2O)4,首次用X-射线单晶衍射仪测定了其晶体结构,同时使用G03程序对该化合物进行了量子化学计算,探讨了化合物的Wiberg键级、电荷布居及前线分子轨道的能量、原子轨道布居规律.结果表明:该晶体属三斜晶系,空间群P(1),晶胞参数为:a=0.6347(3)nm,b=0.6922(3)nm,c=0.9286(4)nm,α=96.226(7)°,β=104.929(6)°,γ=112.939(6)°,V=0.352 9(3)nm3,Dc=1.747 g/cm3,Z=1,F(000)=191.最终偏离因子R1=0.045 7,wR2=0.1368.在标题化合物中2个异烟酸根的2个氮原子及4个水分子与Mn(Ⅱ)配位,形成了六配位的变形八面体结构.标题化合物的总能量为-688.647 2 au,最高占据轨道HOMO的能量为-0.296 57 a.u,最低空轨道LUMO的能量为-0.00904 a.u,两前沿轨道的能量间隙为0.305 61 a.u.其能级间隙值较大,说明标题化合物基态的稳定性较好;同时其Wiberg键级及电荷布居的数据与晶体测试结果相吻合,表明理论化学的方法应用于该化合物结构的研究较令人满意.     

C~2-(C~3-) Continuous Interpolation Spline Curve and Surface

Free-formed or sculptured surfaces in engineering products are frequently constructed from a set of measured 3D data points.C^2-(C^3-)continuity approach is important in this field.This paper presents a method of rectangular interpolation of given 3D data array which is regularly arranged.The interpolation surface which is constructed by tensor product has dsirable properties(second-order or third-order continuity,locality)and is implemented and adjusted easily,Higher order continuity methods are also briefly discussed.     

Theoretical investigation on gas-phase reaction of CF3CH2OCH3 with OH radicals and fate of alkoxy radicals (CF3CH(O)OCH3/CF3CH2OCH2O)

Detailed theoretical investigation has been performed on the mechanism, kinetics and thermochemistry of the gas phase reactions of CF₃CH₂OCH₃ (HFE-263fb2) with OH radicals using ab-initio and DFT methods. Reaction profiles are modeled including the formation of pre-reactive and post-reactive complexes at entrance and exit channels, respectively. Our calculations reveal that hydrogen abstraction from the CH₂ group is thermodynamically and kinetically more facile than that from the CH₃ group. Using group-balanced isodesmic reactions, the standard enthalpies of formation for CF₃CH₂OCH₃ and radicals (CF₃CHOCH₃ and CF₃CH₂OCH₂) are also reported for the first time. The calculated bond dissociation energies for the CH bonds are in good agreement with experimental results. At 298 K, the calculated total rate coefficient for CF₃CH₂OCH₃ + OH reactions is found to be in good agreement with the experimental results. The atmospheric fate of the alkoxy radicals, CF₃CH(O)OCH₃ and CF₃CH₂OCH₂O are also investigated for the first time using the same level of theory. Out of three plausible decomposition channels, our results clearly point out that reaction with O₂ is not the dominant path leading to the formation of CF₃C(O)OCH₃ for the decomposition of CF₃CH(O)OCH₃ radical in the atmosphere. This is in accord with the recent report of Osterstrom et al. [CPL 524 (2012) 32] but found to be in contradiction with experimental finding of Oyaro et al. [JPCA 109 (2005) 337].     

茂金属卡宾配合物{(eta~5-C_5H_5)MoX(CO)_2[C(CH_2)_2CH_2O]}(X:Cl、Br、I)的电子结构研究

运用G98W程序,采用Lanl2dz基组,对茂金属配合物{(eta~5-C_5H_5)MoX(CO)_2[C(CH_2)_2CH_2O]}(X:Cl、Br、I)进行从头算研究,探讨配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律,以及一些前沿分子轨道的组成特征等。结果表明,标题配合物结构在能量上是稳定的,因而能作为结构单元而存在。为茂金属配合物的合成、分子组装提供理论参考。     

Phase equilibria study in the system “Fe2O3”-ZnO-Al2O3-(PbO+CaO+SiO2) in air

Phase equilibria studies have been undertaken first time in the system PbO-“FeO_x”-CaO-SiO₂-ZnO-Al₂O₃. Pseudo-ternary section of the phase diagram “Fe₂O₃”-ZnO-(PbO + CaO + SiO₂) with CaO/SiO₂ weight ratio of 0.93 and PbO/(CaO + SiO₂) weight ratio of 2.0 at fixed 4 wt% Al₂O₃ has been constructed by equilibration and quenching technique. Zincite, spinel, melilite and Ca₂SiO₄ are the major primary phases in the temperature and composition ranges investigated. It was found that, Al₂O₃ stabilizes the spinel and melilite phases and extents their primary phase fields. The liquidus temperatures are increased in the spinel primary phase filed and decreased in the zincite primary phase field with increasing Al₂O₃. Significant difference of the liquidus temperatures is observed between the experimental data and FactSage calculations. Accurate compositions of the solid solutions have been determined in the present study together with the accurate temperature and liquid compositions. This study can provide direct support for industrial practice and optimization of the thermodynamic database.