首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
本文用微正则过渡态理论计算了H+O_2(n_0,j_0)→HO+O和C+H_2(n_0,j_0)→CH+H在ab initio势能面上的选态反应截面σ_(n_0,j_0);E.分析了势能面性质对反应截面的影响。计算结果表明,在指定反应物分子的振动态n_0、转动态j_0时,两个反应体系的反应截面随相对平动能的增加先是增加后是减小(j_0=1,n_0=0除外);在给定相对平动能和反应物分子的转动态j_0时,随反应物分子的振动量子数n_0的增加,两个体系的选态反应截面均有较显著的增加,在指定相对平动能和反应物分子的振动态n_0时,H+O_2体系的选态反应截面随j_0的变化较为复杂,而C+H_2体系则比较简单(j_0=1除外).对于H+O_2反应体系,本文得到的反应截面与实验结果及准经典轨迹理论的计算结果符合得很好。  相似文献   

2.
本文用微正则过渡态理论计算了H+O_2(n_0,j_0)→HO+O和C+H_2(n_0, j_0)→CH+H在ab initio势能面上的选态反应截面σ_(n_0,j_0); E.分析了势能面性质对反应截面的影响。计算结果表明, 在指定反应物分子的振动态n_0、转动态j_0时, 两个反应体系的反应截面随相对平动能的增加先是增加后是减小(j_0=1, n_0=0除外); 在给定相对平动能和反应物分子的转动态j_0时, 随反应物分子的振动量子数n_0的增加, 两个体系的选态反应截面均有较显著的增加, 在指定相对平动能和反应物分子的振动态n_0时, H+O_2体系的选态反应截面随j_0的变化较为复杂, 而C+H_2体系则比较简单(j_0=1除外)。对于H+O_2反应体系, 本文得到的反应截面与实验结果及准经典轨迹理论的计算结果符合得很好。  相似文献   

3.
<正>Quasi-classical trajectory(QCT) calculations have been carried out to study the generalized polarization dependent differentialcross sections(PDDCSs) for the reactions H + LiH~+(v = 0,j = 0)→H_2 + Li~+ and H~+ + LiH(v = 0,j = 0)→H_2~+ + Li occurring onthe two lowest-lying electronic states of the LiH_2~+ system,using the ab initio potential energy surfaces(PESs) of Martinazzo et al.[3].Four PDDCSs,i.e.,(2π/σ)(dσ_(00)/dω_t),(2π/σ)(dσ_(20)/dω_t),(2π/σ)(dσ_(22+)/dω_t),(2π/σ)(dσ_(21-)/dω_t) have been discussed in detail.  相似文献   

4.
基于Aguado等人拟合的APW势能面(PES),运用准经典轨线(QCT)方法,对反应Li+HF(v=0,j=0)→LiF+H的动力学性质进行了计算.主要研究了不同碰撞能条件下的反应截面、转动取向、产物散射角分布和竞争反应模式等.结果表明,该反应存在直接提取型和间接插入型两种反应模式,在低能量下反应以间接插入反应模式为主,能量大于200 meV时则以直接提取反应为主.  相似文献   

5.
Two new supramolecular compounds,2C 10 H 9 N 2 + ·C 8 HF 4 O 4 2-·C 8 H 2 F 4 O 4 /(H 2 tfbdc)· (tfbdc)·(Hbipy) 2 (1) and C 4 H 6 N 2 2+ ·C 8 HF 4 O 4 2-/(tfbdc)·(H 2 pz) (2),were synthesized and characterized by elemental analysis,IR spectra,and single-crystal X-ray diffraction.Compound 1 crystallizes in the triclinic system,space group P1,with a=8.3453(12),b=10.1798(15),c=10.6626(16),α=87.591(2),β=74.047(2),γ=69.006(2)°,V=834.53(12) 3,D c=1.614 g/cm 3,F(000)=400,u=1.45 cm-1,Z=2,the final R=0.0353 and wR=0.1005 for 5882 observed reflections with I > 2σ(I);and compound 2 crystallizes in the monoclinic system,space group P2 1 /c,with a=10.471(4),b=5.4419(19),c=12.249(4),β=114.909(6)°,V=633(4)3,D c=1.669 g/cm 3,F(000)=320,u=1.63 cm-1,Z=2,the final R=0.0794 and wR=0.2923 for 3213 observed reflections with I > 2σ(I).Both compounds 1 and 2 crystallize as charge-transfer organic salts with the dianionic or neutral acid components lying at the inversion centers.Hbipy + cations and anionic acid in compound 1 are linked to form a chain by means of C-H···O hydrogen bonds.Adjacent chains are further extended into a two-dimensional layer network via N-H···O and O-H···N hydrogen bonds.In compound 2,the acid and base subunits are arranged alternately to generate a linear tape motif via N-H O hydrogen bonds;these tapes are further combined into a three-dimensional array with CdSO 4 topology via C-H O intermolecular hydrogen bonds.  相似文献   

6.
采用量子化学的密度泛函B3LYP和二阶微扰MP2(full)方法对C4H4Y(Y=O,S,Se)与BX3(X=H,F,Cl)形成的电子授受型复合物进行了研究,所得18个复合物的构型包括BX3位于C=C双键上方的π-p作用型和B与O,S,Se直接作用的n-p作用型.体系C4H4Y-BH3以n-p作用型较为稳定,体系C4H4Y-BF3,C4H4Y-BCl3的π-p和n-p作用型复合物稳定性相当.对各复合物的几何构型、振动频率和自然键轨道分析表明,复合物的形成过程中均存在几何构型的改变、电荷的转移和振动频率的变化,它们的变化规律与复合物稳定性的变化规律基本一致,即按H,F,Cl的顺序依次降低.  相似文献   

7.
<正> The title compound C18H37O20NCeCl3, Mr = 834. 25, orthorhom-bic, P212121, a = 11.836(4), b = 13.899(6), c= 19. 401(6) A ; V=3192(2)A3; Z = 4; Dc=1. 74gcm-3, F (000) = 1684,μ= 17. 8cm-1 (MoKa). The final R = 0. 080, Rw = 0. 081. The Ce(Ⅲ) ion is coordinated to one O atom of one C1O4- ion, a CH3CN molecule, a water molecule and seven O atoms from a crown ether molecule. The other two C1O4- ions are not coordinated to the metal. The bond lengths of Ce-N(CH3CN), Ce -O(ClO4-), Ce -O(H2O) and Ce-O(crown) are 2. 61,2. 82,2. 53, and 2. 56A, respectively.  相似文献   

8.
A manganese(II) complex (tataH)2[Mn(pydc)2]·4H2O (C20H28MnN14O12, Mr = 711.50, tata = 2,4,6-triamino-1,3,5-triazine, pydcH2 = pyridine-2,6-dicarboxylic acid) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1, with a = 9.9847(3), b = 10.9813(3), c = 15.2616(5) , α = 101.5310(10), β = 90.2610(10), γ = 116.4600(10)°, V = 1459.44(8) 3, Z = 2, Dc = 1.619 g/cm3, μ = 0.539 mm–1, F(000) = 734, the final R = 0.0292 and wR = 0.0745. In the crystal the MnII atom is six-coordinated by four carbonyl oxygen atoms and two pyridine nitrogen atoms from two tridentate pydc ligands to furnish a distorted octahedral geometry. The complex shows the A…D…D’…A’ H-bonded tetramer. The molecules are packed in a three-dimensional framework structure by the combination of O–H…O, N–H…O and N–H…N hydrogen bonds between (tataH)+, [Mn(pydc)2]2– and crystal water.  相似文献   

9.
Reactions of NiCl2·6H2O with dmpzm and formic or acetic acid at PH = 7 pro- duced the two title compounds, [Ni(dmpzm)2(HCO2)]Cl·2H2O 1 and [Ni(dmpzm)2(Oac)]Cl·3H2O 2 (dmpzm = 1,1'-methylenebis(3,5-dimethyl-1H-pyrazole)). 1 and 2 were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. 1 crystallizes in the orthorhombic system, space group Pcca with a = 18.700(2), b = 8.6843(9), c = 18.098(2)(A), V = 2939.1(5)(A)3, Z = 4, Dc = 1.319 g/cm3, T = 193 K, C23H37ClN8NiO4, Mr = 583.75, F(000) = 1232, μ(MoKα) = 0.792 cm(1, S = 1.079, R = 0.0772 and wR = 0.1958 for 2265 observed reflections with I > 2σ(I). 2 crystallizes in the orthorhombic system, space group Pcca with a = 17.011(3), b = 18.630(4), c = 19.300(4)(A), V = 6117(2)(A)3, Z = 8, Dc = 1.337 g/cm3, T = 193(2) K, C24H41ClN8NiO5, Mr = 615.79, F(000) = 2608, μ(MoKα) = 0.768 cm(1, S = 1.059, R = 0.0518 and wR = 0.1109 for 5124 observed reflections with I > 2σ(I). The Ni atoms in 1 or 2 are chelated by two dmpzm ligands and one formate or acetate anion, forming slightly distorted octahedral geometries. In the crystals of 1 or 2, intermolecular hydrogen bonding interactions result in the formation of 2D hydrogen-bonded frameworks.  相似文献   

10.
采用密度泛函理论研究了过渡金属钒族氧化物阳离子团簇(M2O5)+m=1,2(M=V, Nb, Ta)与C2H4气相反应机理. 反应为(M2O5)m++C2H4→(M2O5)m-1M2O4++C2H4O, 反应物先化合生成C—O键相连的化合物, 经过过渡态后M—O键断裂, 从而发生氧原子转移到碳氢化合物上的反应. 对于V2O5+与C2H4的反应, 存在经顺式和反式两种过渡态结构路径, 从能量上看, 经反式过渡态结构的路径更有利. 计算结果表明, 发生反应时C2H4与钒氧化物阳离子反应大量放热, 而与铌、钽氧化物阳离子反应却放热较少甚至不放热, 这与实验结果一致. 钒、铌、钽氧化物阳离子团簇发生氧转移反应活性不同的原因是金属-氧键的强弱不同所致.  相似文献   

11.
A manganese(Ⅱ) complex (tataH)2[Mn(pydc)2]·4H2O (C20H28MnN14O12, Mr = 711.50, tata = 2,4,6-triamino-1,3,5-triazine, pydcH2 = pyridine-2,6-dicarboxylic acid) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1, with a = 9.9847(3), b = 10.9813(3), c = 15.2616(5) (A), α =101.5310(10), β = 90.2610(10), γ = 116.4600(10)°, V = 1459.44(8) A3, Z = 2, Dc = 1.619 g/cm3, μ = 0.539 mm-1, F(000) = 734, the final R = 0.0292 and wR = 0.0745. In the crystal the MnⅡ atom is six-coordinated by four carbonyl oxygen atoms and two pyridine nitrogen atoms from two tridentate H-bonded tetramer. The molecules are packed in a three-dimensional framework structure by the combination of O-H…O,N-H…O and N-H…N hydrogen bonds between (tataH) ,[Mn(pydc)2]2- and crystal water.  相似文献   

12.
采用DFT B3LYP和QCISD方法研究了不饱和类锗烯H2C=GeLiCl与RH(R=F, OH, NH2)的插入反应. 在B3LYP/6-311+G(d,p)水平上优化了反应势能面上的驻点构型. 结果表明, H2C=GeLiCl与HF、H2O 或NH3发生插入反应的机理相同. QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p)计算的三个反应的势垒分别为173.53、194.48和209.05 kJ·mol-1, 反应热分别为60.18、72.93和75.34 kJ·mol-1. 相同条件下发生插入反应时, 反应活性顺序都是H—F>H—OH>H—NH2.  相似文献   

13.
A new nickel citrate compound Ni(H2cit)(phen)(H2O).3H2O(H4cit = citrate acid,phen = 1,10-phenanthroline) has been synthesized and characterized by single-crystal X-ray diffraction.It crystallizes in the trigonal system,space group P31 with a = 13.8319(13),c = 10.425(2),V = 1727.3(4)3,Dc = 1.445 g/cm3,Mr = 501.09,F(000) = 780,μ = 0.901 mm-1,Z = 3,R = 0.0760 and wR = 0.1730 for 3859 observed reflections(I > 2σ(I)).In this compound,Ni2+ cation is chelated by a phen molecule,one H2cit2-anion and one H2O molecule.The citric acid coordinates to the Ni2+ center through three functional groups:α-hydroxyl,α-carboxylate and β-carboxylate while another α-carboxylate forms hydrogen bond with surrounding H2O molecule.And the citric acid is doubly protonated.The temperature-dependent magnetic susceptibility data revealed that the compound is a paramagnetic material.  相似文献   

14.
The title compounds, [Co(H2O)6](OVA)2·2H2O 1, [Ni(H2O)6](OVA)2·2H2O 2 and [Zn(OVA)2·2H2O] 3 (HOVA = o-vanillic acid = 2-hydroxy-3-methoxybenzoate), were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR and TGA. Compounds 1 and 2 are both of triclinic with space group P1. The metal atom coordinated by six water molecules displays a slightly distorted octahedral configuration. Interestingly, the carboxyl group from HOVA ligand does not coordinate to the metal atom. Correspondingly, compound 3 belongs to the monoclinic system, space group C2/c. Each zinc(Ⅱ) atom exhibits a distorted four-coordinated tetrahedral geometry. Two monodentate carboxyl groups link one zinc(Ⅱ) atom to form a mononuclear molecule. The structure feature is different from that of compounds 1 and 2, which could be attributed to the different coordinated numbers and radii of Co(Ⅱ), Ni(Ⅱ) and Zn(Ⅱ) atoms.  相似文献   

15.
采用1H NMR谱研究了通式为[M3ⅢO(OOCR)6L3]+(M=Cr,Fe,Mn;R=CH3,C2H5,CH2NH2;L=C5H5N,H2O)的一系列氧心三核过渡金属配合物,主要考察其1H化学位移随金属、配体、温度、溶剂等因素变化而变化的规律.结果表明,骨架金属对化学位移的影响最大,M3O中的3个金属离子间存在反铁磁交换相互作用.对Mn配合物中顺磁中心对化学位移和线宽的影响机制的研究表明,其1H各向同性位移主要由接触作用贡献.  相似文献   

16.
Reactions of NiCl2·6H2O with dmpzm and formic or acetic acid at PH = 7 pro- duced the two title compounds, [Ni(dmpzm)2(HCO2)]Cl·2H2O 1 and [Ni(dmpzm)2(OAc)]Cl·3H2O 2 (dmpzm = 1,1'-methylenebis(3,5-dimethyl-1H-pyrazole)). 1 and 2 were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. 1 crystallizes in the orthorhombic system, space group Pcca with a = 18.700(2), b = 8.6843(9), c = 18.098(2) , V = 2939.1(5) 3, Z = 4, Dc = 1.319 g/cm3, T = 193 K, C23H37ClN8NiO4, Mr = 583.75, F(000) = 1232, μ(MoKα) = 0.792 cm-1, S = 1.079, R = 0.0772 and wR = 0.1958 for 2265 observed reflections with I > 2σ(I). 2 crystallizes in the orthorhombic system, space group Pcca with a = 17.011(3), b = 18.630(4), c = 19.300(4) , V = 6117(2) 3, Z = 8, Dc = 1.337 g/cm3, T = 193(2) K, C24H41ClN8NiO5, Mr = 615.79, F(000) = 2608, μ(MoKα) = 0.768 cm-1, S = 1.059, R = 0.0518 and wR = 0.1109 for 5124 observed reflections with I > 2σ(I). The Ni atoms in 1 or 2 are chelated by two dmpzm ligands and one formate or acetate anion, forming slightly distorted octahedral geometries. In the crystals of 1 or 2, intermolecular hydrogen bonding interactions result in the formation of 2D hydrogen-bonded frameworks.  相似文献   

17.
The title compound, [Cu3(dmpzm)4(μ-1,3-dca)2(dca)4]·2H2O (dmpzm = 1,1'-methyle- nebis(3,5-dimethyl-1H-pyrazole), dca = dicyanamide) 1·2H2O, was synthesized via the reaction of CuCl2·2H2O with dmpzm and Na(dca), and characterized by elemental analysis and IR spectra. 1·2H2O crystallizes in the monoclinic system, space group C2/m with a = 13.578(3), b = 16.769(3), c = 14.769(3)(A),β=104.10(3)°, V = 3261.4(11)(A)3, Z = 2, Dc = 1.466 g/cm3, T = 153(2) K, C56H68N34O2Cu3, Mr = 1440.09, F(000) = 1490, μ(MoKα) = 1.040 mm(1, S = 1.150, R = 0.0553 and wR = 0.1123 for 2744 observed reflections with I > 2σ(I). The central copper atom is chelated by two dmpzm ligands and coordinated by two bridging dca anions, forming a slightly distorted octahedral geometry. The two external copper atoms adopt a square-pyramidal coordination geometry, coor- dinated by one chelating dmpzm ligand and one bridging and two terminal dca anions. Two inter- molecular hydrogen bonding interactions result in the formation of a 2D (4,4) hydrogen-bonded network.  相似文献   

18.
<正> C100H78, (A: C36H28, B: C28H22) Mr = 1279. 74, monoclinic, P21/a, a=17. 282(3), b=10. 669(4), c= 19, 927(3) A , β =102. 99(1)°,V = 3580. 1(2) A3, Z=2, μ(MoKα) = 0. 623cm-1, F(000) = 1356, Dc=1. 187g/cm3, room temperature. The final R=0. 084, Rw = 0. 086 for 1255 independent observed reflections (I≥3σ(I)). Owing to the existence of 1,6,7, 8-Tetraphenyl (3,4-benzo)-bicyclo[4, 2, 0]octa-7-ene(A) , cis, cts-1, 2, 3, 4-Tetraphenylbutadiene (B) in A2B can take the different conformation from the one in the pure B crystal. The reason of the formation of this molecular compound crystal is put forward.  相似文献   

19.
用量子化学UMP2方法,在6-311++G**基组水平上研究了CH2X(X=H,F,Cl)与臭氧反应机理,全参数优化了反应过程中反应物、中间体、过渡态和产物的几何构型,在UQCISD(T)/6-311++G**水平上计算了它们的能量,并对它们进行了振动分析,以确定中间体和过渡态的真实性.从CH2X(X=H,F,Cl)与O3的反应机理的研究结果看,它们与O3反应的活性都比较强,相对而言,活性大小顺序为CH2F>CH3>CH2Cl,也就是说,CH2F自由基与臭氧间的反应活性最强,对大气臭氧的损耗将是最大的.同时研究还发现CH2X(X=H,F,Cl)系列自由基与O3的反应都是强放热反应.  相似文献   

20.
A new dinuclear manganese complex [Mn2(L)2(2,2'-bipy)2(H2O)5]2·3H2O has been synthesized with Mn SO4·H2O, 2,2'-bibenzoic acid(H2L) and 2,2'-bipyridine(2,2'-bipy) in the mixed solvent ethanol and water. It crystallizes in monoclinic, space group P1 with a = 9.9944(10), b = 21.939(2), c = 25.628(3) ?, α = 108.429(3), β = 100.613(4), γ = 102.821(3)o, V = 4997.9(9) ?3, Dc = 1.355 g/cm3, Z = 2, F(000) = 2108, GOOF = 1.074, the R = 0.0626 and w R = 0.1531. The structure of the complex contains two [Mn2(L)2(2,2'-bipy)2] units, ten coordinated H2 O molecules and three uncoordinated H2 O molecules. The fluorescence, thermal stability and magnetic properties of the complex were investigated.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号