N2在Pd金属表面的吸附行为

对Pd原子采用相对论有效原子实势(RECP/SDD), N原子采用AUG-cc-pVTZ基函数, 利用B3LYP方法计算了PdN和PdN2分子的微观结构以及不同温度下的热力学函数. 以气态分子总能量中的振动能EV代替该分子处于固态时的振动能量, 以电子运动和振动运动熵SEV代替分子处于固态的熵的近似方法, 计算了不同温度下金属Pd与N2反应的ΔHӨ、ΔSӨ、ΔGӨ及氮化反应平衡压力, 导出了氮化反应平衡压力与温度的关系. 由此可看出, 在常压及298.15～998.15 K温度条件下, N2在金属Pd表面的吸附过程以Pd(s) + N2 = PdN2(s)反应进行. 计算得出在标准条件下, PdN(s)的生成焓为254.37 kJ·mol-1, PdN2(s)的生成焓为－80.59 kJ·mol-1. 并与Pd氢化反应平衡压力比较, 得到平衡常数Kp(N2)比Kp(H2)约小两个数量级, 说明N2较难被金属Pd表面吸附, 在热力学上有利于氢置换氮.     

PdH2、YH2分子的结构与势能函数

用密度泛函理论的B3LYP方法,对钯和钇原子采用SDD收缩价基函数,氢原子采用6-311＋＋G**全电子基函数,对PdH2和YH2体系的结构进行优化计算,得到PdH2分子最稳态为C2v构型,电子组态为1A1,平衡核间距RPdH=0.1692 nm,键角∠HPdH=29.4°,离解能De=5.5212 eV,基态简正振动频率:ν1(b2)=1470.1 cm－1、ν2(a1)=1007.9 cm－1、ν3(a1)=2907.0 cm－1.YH2分子最稳态也为C2v构型,电子组态2A1,RYH=0.1962 nm,∠HYH=114.3°,De=5.6691 eV,基态简正振动频率:ν1(b2)=1457.9 cm－1、ν2(a1)=476.0 cm－1、ν3(a1)=1506.3 cm－1.由微观过程的可逆性原理分析了分子的可能离解极限.并用多体项展式理论方法分别导出基态PdH2和YH2分子的势能函数,其等值势能面图准确地再现了PdH2和YH2分子的结构特征和离解能,由此讨论了Pd ＋ H2和Y ＋ H2分子反应的势能面静态特征.     

PuC和PuC2的分子结构与势能函数

采用密度泛函B3LYP方法和相对论有效原子实理论模型优化出PuC和PuC2分子稳定构型,其电子状态分别为X5Σ－和X5A2.PuC2分子为C2v构型,其∠CPuC=147.67°,平衡核间距Re=0.22819 nm, 离解能De=5.543 eV, 并计算出谐振动频率:ν1=61.736 cm－1、ν2=229.894 cm－1、ν3=305.582 cm－1.在此基础上,运用多体项展式理论方法,导出了基态PuC2分子的分析势能函数,该势能面准确地再现了PuC2分子的稳定结构,并根据势能面等值图讨论了PuC＋C反应和Pu＋C2反应的势能面静态特征.     

二氧化钚分子的多体展式势能函数

从导出基态PuO2分子的电子状态X5Σ g正确地判断其离解极限出发,采用MP2方法,应用相对论有效原子实模型(RECP)优化出PuO2(X5Σ g)分子稳定构型为线性OPuO(D∞h),其平衡核间距Re=0.18004nm.同时也计算出振动频率,并优化出存在亚稳态的Pu-O-O(C∞v)构型.使用多体项展式理论方法,导出了基态PuO2分子的分析势能函数.该势能表面准确地再现了O-Pu-O(D∞h)平衡结构和亚稳态的Pu-O-O(C∞v)构型.然后根据势能函数等值图讨论了O(3Pg) PuO反应的势能面静态特征.     

两个异亚硝基乙酰丙酮-N-芳基亚胺Pd(Ⅱ)配合物的合成、谱学性质和PdCl(C_6H_5—IAI)(C_6H_5NH_2)的晶体结构

合成了两个异亚硝基乙酰丙酮 N 芳基亚胺的Pd(Ⅱ )配合物 ,PdCl(C6H5—IAI) (C6H5NH2 ) ( 1 )和PdCl( p CH3 C6H4 —IAI) ( p CH3 C6H4 NH2 ) ( 2 ) ,并测定了配合物 1的晶体结构 .配合物 1晶体属正交晶系 ,空间群为Pca2 1,晶胞参数a =1 .8587( 4 )nm ,b=0 .93 80 ( 2 )nm ,c=2 .1 2 3 7( 4 )nm ,Z =8,F( 0 0 0 ) =1760 ,μ =1 .1 60mm-1,R1=0 .0 2 71 .二齿Schiff碱配体的异亚硝基 (肟基 )的N原子和亚胺的N原子 ,苯胺基N原子和Cl-离子与Pd(Ⅱ )配位 ,形成PdN3 Cl平面正方形配位构型 .红外和喇曼光谱表明 ,形成配合物后νCO和νCN移向低频 ,而νN—O则移向高频 .电子光谱说明存在π π 和d π 跃迁     

Li_2H分子电子基态的从头算势能面及其振动激发态

用ab initio MRSDCI/6-311G(2 df,2 Pd)方法研究了Li_2H分子电子基态的势能面,计算了285个几何构型点的势能值,并采用Simons-Parr-Finlan展开式对这些势能值进行了拟合,得到均方差X~2等于4.64×10~(-6)(hartree~2).Li_2H分子电子基态的平衡几何构型为R_e=0.172nm,相似文献   

PdYH分子的结构与势能函数

用密度泛函理论的B3LYP方法, 对钯和钇原子采用SDD收缩价基函数, 氢原子采用6-311＋＋G**全电子基函数, 对PdY和PdYH体系的结构进行优化. 计算表明: PdY分子的几何构型为C_∞v, 其基态为X²Σ^＋态, 键长R＝0.24168 nm, 离解能为D_e＝2.8261 eV, 谐振频率ω_e＝254.0656 cm^－1, 并拟合得到Murrell-Sorbie势能函数; PdYH分子最稳态为C_s构型, 电子组态为¹A', 平衡核间距R_PdY＝0.24281 nm, R_YH＝0.19824 nm, 键角∠PdYH＝116.7157°, 离解能D_e＝5.6146 eV, 基态简正振动频率: 对称伸缩振动频率ν₁ (a')＝348.2909 cm^－1, 弯曲振动频率ν₂ (a')＝243.3382 cm^－1, 反对称伸缩振动频率ν₃ (a')＝1442.2695 cm^－1. 由微观过程的可逆性原理分析了分子的可能离解极限. 并用多体项展式理论方法分别导出基态PdY和PdYH分子的势能函数, 其等值势能面图准确地再现了PdY和PdYH分子的结构特征和离解能, 由此讨论了Pd＋Y＋H分子反应的势能面静态特征.     

C2F5I分子C-I键解离的自旋-轨道从头算研究

采用考虑相对论效应的6-311G**全电子基组与多参考微扰理论, 计算了该分子的包含自旋-轨道耦合效应的垂直激发能和基态、激发态C—I键解离势能曲线. 理论计算发现, 势能曲线33A'与11A', 21A'出现交叉, 交叉区域在C—I键长为0.241 nm附近; 基态11A'到激发态33A'(3Q0)的垂直激发能为4.658 eV, 与实验值4.662 eV非常吻合. 讨论了C2F5I分子作为碘激光介质的可行性.     

两个异亚硝基乙酰丙酮-n-芳基亚胺Pd(Ⅱ)配合物的合成、谱学性质和PdCl(C6H5一IAI)(C6H5NH2)的晶体结构

合成了两个异亚硝基乙酰丙酮-n-芳基亚胺的Pd(Ⅱ)配合物,PdCl(C6H5一IAI)(C6H5NH2)(1)和PdCl(P-CH3C6H4－IAI)(P-CH3C6HtNH2)(2),并测定了配合物1的晶体结构.配合物1晶体属正交晶系,空间群为Pca2l,晶胞参数a一1.858 7(4)nm,b＝0.938 0(2)nm,c一2.123 7(4)nm,2=8,F(000)一1 760,μ＝1.160 mm-1,R1＝O.027 二齿Schiff碱配体的异亚硝基(肟基)的N原子和亚胺的N原子,苯胺基N原子和CL-离子与Pd(Ⅱ)配位,形成PdN3Cl平面正方形配位构型.红外和喇曼光谱表明,形成配合物后νC=O和νc=N 移向低频,而vN-.o则移向高频.电子光谱说明存在π-π*和d-π*跃迁     

水蒸汽在Pd表面吸附的热力学

用密度泛函方法和相对论有效原子实势分别对PdOH2、PdOH 及PdO 的几何构型进行了优化, 得到PdOH2分子为Cs构型, Pd 与H2O 分子不在同一平面, RPdO=0.2283 nm; PdOH 分子为2A'态, RPdO=0.1965 nm, ROH=0.0968 nm, ∠PdOH=110.186°; PdO分子基态为3Π, RPdO=0.1858 nm. 根据电子-振动近似理论计算了不同温度下金属Pd与H2O、OH及游离态O原子反应的生成热力学函数, 导出了反应平衡压力随温度的变化关系, 分析认为水蒸汽引起Pd合金膜中毒是由于H2O分子的离解产物OH和O原子吸附在膜表面所致.     

Cu3PdN nanocrystals electrocatalyst for formic acid oxidation

We report a hot-injection method to fabricate monodispersed Cu₃PdN nanoparticles (NPs). The crystal structure, morphology, and chemical composition of the as-synthesized Cu₃PdN have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. The as-developed Cu₃PdN NPs electrocatalysts show improved activity and enhanced stability for formic acid oxidation compared with the corresponding Pd and Cu₃Pd NPs.     

The Novel Benzo-15-Crown-5 with Palladium(II) Complex:[Na(B15C5)]2[Pd(SCN)4]

A novel Pd(II) Benzo-15-crown-5 complex [Na(B15C5)]2[Pd(SCN)4] has been isolated and characterized by IR and X-ray diffraction analysis.The crystal structure belongs to monoclinic,space group P21/n with cell dimensions,a=1.0164(6),b=1.3743(3),c=1.4987(7) nm,b=95.248(6)o ,V=2.0847nm3,Z=2,F(000)=944,R=0.053,Rw=0.072.The compound consists of two [Na(B15C5)]+ complex cations and a [Pd(SCN)4]2- complex anion.Each sodium ion is coordinated by five crown ether oxygen atoms and one N atom from the SCN group of [Pd(SCN)4]2- to form stable neutral complex.     

基态UC2分子的结构和势能函数

采用密度泛函理论(DFT)的B3LYP方法和相对论有效原子实势理论模型(RECP),对UC2分子可能的结构进行优化计算,得到UC2分子稳定构型为角形C-U-C(C2v);由微观可逆性原理,判断了UC2分子的离解极限;并且导出了基态UC2分子(X 5B1)的多体项展式势能函数,其势能面等值图展现了C-U-C(C2v)稳定结构;根据势能面等值图,讨论了C+UC(X 3П)反应和U+C2(X 1∑+g)反应的势能面静态特征.     

相转移法制备PdMo催化剂及其氧还原活性

以四丁基氢氧化铵作为相转移剂,以硼氢化钠为还原剂,利用相转移法在二氯甲烷中制备了一系列不同比例的Pd_xMo/C(Pd/Mo的原子比x=1、2、3、4、5)催化剂。透射电镜(TEM)图像显示,Pd_x Mo/C是呈2～4 nm的圆形颗粒,尺寸均匀、分散性良好。X射线衍射(XRD)结果表明,加入第二组元Mo后,Pd的晶格发生扩张,调节了 Pd的几何结构。此外,X射线光电子能谱(XPS)结果表明,相对于Pd/C,Pd_4Mo/C的Pd3d_(5/)2结合能负移了 0.50 eV,说明电负性较大的Pd从Mo吸电子,电子结构发生改变。氧还原反应(ORR)结果表明,不同比例的Pd_xMo/C催化剂活性均优于Pd/C,其中当x=4时,ORR活性最佳,其起始电位和半波电位分别为0.876和0.813 V,高于商业Pt/C的0.870和0.810 V。此外,在经过3 h的运行之后电流密度仍保留82.9%,与商业Pt/C相比具有明显的优势。     

Synthesis and Crystal Structure of Bis(isonitrosoethylacetoacetate- N- benzylimino) palladium (Ⅱ)

The title complex Pd(C13H15N2O3)2(C13H15N2O3))- is the anion of isonitrosoethylacetoacetate-N-benzylimine) crystallizes in the monoclinic system, space group P21/c with a= 8. 197(2), b= 14. 524(3), c= 10. 835(2) A , β= 101.77(3)°, V= 1262. 8(5) A3, Dc=1. 580 g/cm3, F(000)=616, Mr= 600. 94, μ(MoKα) =0. 784mm-1, Z=2 and final R=0. 0410 and wR=0. 0962 for 1855 observed reflections [I≥2σ(I)]. The geometry around the palladium atom is a distorted trans PdN4 square plane, the Schiff base ligand C6H5CH2-IEAI- being coordinated through its oximo-nitrogen atom and imino-nitrogen atom.     

Synthesis, X-ray structure, electrochemistry, and theoretical studies of palladium(II) complex with a tetradentate bis(quinoline-2-carboxamide) ligand

The title complex [Pd(Me₂bqb)] (1), [Me₂bqb^2?C?=?1,2-bis(quinoline-2-carboxamide)-4,5-dimethyl-benzene dianion], has been synthesized and characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structure of [Pd(Me₂bqb)] has been determined by X-ray crystallography. The complex exhibits distorted square-planar PdN4 coordination geometry with two short and two long Pd?CN bonds (Pd?CN ~1.957 and ~2.095 ?, respectively). In addition to the molecular geometry from X-ray experiment, theoretical studies have been carried out on the structure of the complex at the density functional theory (DFT-B3LYP) level in conjunction with effective core potential basis set (LANL2DZ) for Pd atom and 6-311++G(d,p) basis set for N, O, C and H atoms. Electrochemical studies in CH₂Cl₂ solution revealed A reversible redox process corresponding to the Pd^II/Pd^III couple with E _1/2 at 0.924?V (vs. SCE).     

Photoelectron spectroscopy and Ab initio study of the structure and bonding of Al7N- and Al7N

The electronic and geometrical structures of Al7N- are investigated using photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of Al7N- have been obtained at three photon energies with six resolved spectral features at 193 nm. The spectral features of Al7N- are relatively broad, in particular for the ground state transition, indicating a large geometrical change from the ground state of Al7N- to that of Al7N. The ground state vertical detachment energy is measured to be 2.71 eV, whereas only an upper limit of approximately 1.9 eV can be estimated for the ground state adiabatic detachment energy due to the broad detachment band. Global minimum searches for A7N- and Al7N are performed using several theoretical methods. Vertical electron detachment energies are calculated using three different methods for the lowest energy structure and compared with the experimental data. Calculated results are in excellent agreement with the experimental data. The global minimum structure of Al7N- is found to possess C3v symmetry, which can be viewed as an Al atom capping a face of a N-centered Al6N octahedron. In the ground state of Al7N, however, the capping Al atom is pushed inward with the three adjacent Al-Al distances being stretched outward. Thus, even though Al7N still possesses C3v symmetry, it is better viewed as a N-coordinated by seven Al atoms in a cage-like structure. The chemical bonding in Al7N- is discussed on the basis of molecular orbital and natural bond analysis.