(HAlNH)n(n=2～3)环状化合物的结构特征

用自洽场理论 (HF)和密度泛函理论 (DFT)的B3LYP方法 ,在 6 31G 的水平上对化合物(HAlNH) 2 和 (HAlNH) 3 的几何结构进行优化 ,并分别与环丁二烯C4 H4 和苯分子C6H6的结构和成键方式进行比较。以B3LYP STO 3G方法讨论其分子轨道波函数 (Ψ)。结果表明 :C4 H4 和 (HAlNH) 2 均为D2h对称 ,前者为长方形结构 ,形成两个孤立的π键 ;而后者为菱形结构 ,形成一个π44键。C6H6和 (HAlNH) 3分子点群分别为D6h和D3h,并均形成一个π66键。成键原子对分子轨道的贡献不同 ,其中C原子是完全等价的 ,而Al和N原子各不相同 ,N原子比Al的贡献要大得多     

Polymeric (NO)3(N2O) n , (NO)3(N2O) n + , and (NO)3(N2O) n − : an interpretation of experimental observations

Semi-empirical and ab initio calculations are reported which provide a possible explanation for reported experimental results on 2-photon ionization of NO containing a few percent of N₂O, which found (NO)₃(N₂O) _n ^+or? clusters to be significantly more abundant than other (NO) _m (N₂O) _n products. It is found that the observed abundances of (NO)₃(N₂O) _n ionic clusters may be accounted for by the existence of covalent cyclic trimers of nitric oxide attached to oligomers of nitrous oxide. The extra stability of NO trimers in the observed clusters appears to arise from (NO) ₃ ⁺ rather than (NO)₃. Attachment of an (N₂O) _n side chain to (NO) ₃ ⁺ occurs exothermically. It is suggested that the addition of N₂O to cyclic-(NO) ₃ ⁺ might provide a means of making a polymer of nitrous oxide, which could have useful properties.     

Gaussian binning of the vibrational distributions for the Cl + CH4(v(4/2) = 0, 1) → H + CH3Cl(n(1)n(2)n(3)n(4)n(5)n(6)) reactions

We test several binning techniques to obtain mode-specific final-state distributions for polyatomic reactions. Normal mode analysis is done after an exact transformation to the Eckart frame. Standard histogram binning (HB) and three different variants of the energy-based Gaussian binning (1GB) are employed to obtain the probabilities of the vibrational states. We consider the two major issues of the polyatomic quasiclassical product analysis, i.e., (1) rounding the classical action to the nearest integer can result in unphysical states and (2) the normal-mode analysis can break down for highly distorted geometries. We show that 1GB can handle issue 1 when the total vibrational energy is evaluated in the normal mode space using the harmonic approximation and both issues 1 and 2 can be solved when the total vibrational energy is calculated exactly in the Cartesian space. We found that anharmonicity in the quantized energy levels does not have a significant effect on the final-state distributions. Quasiclassical trajectory calculations are performed for the reactant ground-state and bending-excited Cl((2)P(3/2)) + CH(4)(v(4/2) = 0, 1) → H + CH(3)Cl reactions using an ab initio potential energy surface. The product analysis techniques are successfully applied to the CH(3)Cl product molecules and some qualitative features of the results are discussed.     

Conformational structure of N-(silylmethyl)anilines PhNHCH2SiMe n (OEt)3-n (n = 0–3)

As show the data of IR spectroscopy and quantum-chemical calculations (B3LYP/6-311+G**), N-(silylmethyl)anilines PhNHCH₂SiMe _n (OEt)_3?n in inert media have an intramolecular hydrogen bond NH?OSi. N-[(Trimethylsilyl)methyl]aniline PhNHCH₂SiMe₃ in inert solvents exists as a mixture of two conformers close in energy.     

Theoretical studies of the reactions of Cl atoms with CF3CH2OCH n F(3−n) (n = 1, 2, 3)

This paper presents the theoretical studies of the reactions of Cl atoms with CF₃CH₂OCH₃, CF₃CH₂OCH₂F and CF₃CH₂OCHF₂ using an ab initio direct dynamics theory. The geometries and vibrational frequencies of the reactants, complexes, transition states and products are calculated at the MP2/6-31+(d,p) level. The minimum energy path is also calculated at same level. The MC-QCISD method is carried out for further refining the energetic information. The rate constants are evaluated with the canonical variational transition state theory (CVT) and CVT with small curvature tunneling contributions in the temperature range 200–1,500 K. The results are in good agreement with experimental values.     

(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)簇结构及其热力学性质

用HF自洽场理论和密度泛函理论(DFT)的B3LYP方法,在6 31G水平上研究了低聚物(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)簇的几何构型、电子结构和聚合反应热力学性质,比较了两个系列化合物中化学键的强度.结果表明,Cl2AlNH2和H2AlNH2分子为C2 (EC)平面型结构,其中Al－N为由一个σ键和一个键组成的双键.(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)分子为Dnh对称,Al－N是典型的σ单键 .低聚物(Cl2AlNH2)n和(H2AlNH2)n的稳定性顺序分别为: 3 > 2 > 4> 5 > 1和8 > 7 > 9 > 11 > 6.     

Pressure tuning spectroscopy of [Pt3(CO)6]2−n (n=3–5)

The pressure shifts of the first three bands appearing in the visible spectra of [Pt₃(CO)₆]²⁻_n (n = 3–5) have been measured in solution over the range 0–10 kbar. Previous electronic calculations performed on the dimer in conjunction with these results afford a possible set of assignments for the first three bands appearing in the visible spectrum for the dimer.     

Density functional investigations on the (H2O)n·CCH and (H2O)n·HCC complexes (n=1–3)

The electronic structures and energies of (H₂O)_n·CCH and (H₂O)_n·HCC complexes (n=1–3) between CCH and water have been theoretically investigated at the UB3LYP/6-311++G(2df,p)//UB3LYP/6-311G(d,p) level. The complexes with n=2–3 are cyclic structures with homodromic hydrogen-bond chain. The (H₂O)_n·CCH (n=1–3) complexes show increasing stabilities towards CCH- or H₂O-eliminations of 2.3, 5.8 and 7.6 kcal/mol and are energetically more stable than the corresponding (H₂O)_n·HCC complexes by 0.8, 2.7 and 3.4 kcal/mol, respectively, due to the charge-separation-enhanced hydrogen bonds within (H₂O)_n·CCH (n=2,3). Strong interactions between CCH and (H₂O)₂ and (H₂O)₃ clusters suggest special solvent effects of water on the chemical behavior of unsaturated radicals.     

簇合物(F2GaN3)n(n=1～4)的理论研究

采用密度泛函理论B3LYP/6-311+G*方法,计算研究了(F2GaN3)n(n=1～4)簇合物的结构和性质.研究表明,簇合物(F2GaN3)n(n=2～4)的优化构型均拥有Ga-Na-Ga连接的环状结构.讨论了几何参数随聚合度的变化关系.三聚体的船式构象较椅式构象的能量低16 kJ·mol-1,具有S4对称性的四聚...     

Density functional theory study on (F2AlN3) n (n = 1–4) clusters

Possible geometrical structures and relative stabilities of (F₂AlN₃) _n (n = 1–4) clusters were studied using density functional theory at the B3LYP/6-311+G* level. The optimized clusters (F₂AlN₃) _n (n = 2–4) possess cyclic structure containing Al–N_α–Al linkages, and azido in azides has linear structure. The IR spectra of the optimized (F₂AlN₃) _n (n = 1–4) clusters have three vibrational sections, the whole strongest vibrational peaks lie in 2218–2246 cm⁻¹, and the vibrational modes are N₃ asymmetric stretching vibrations. Trends in thermodynamic properties with temperature and oligomerization degree n are discussed, respectively. A study of their thermodynamic properties suggests that monomer 1A forms the most stable clusters (2A, 3A, and 4B) can occur spontaneously in the gas phase at temperatures up to 800 K.     

[Gd(3-HPYA)3(H2O)]n的合成及其晶体结构

3-(3-吡啶基)丙烯酸(3-HPYA)配体与稀土金属离子钆(Gd)通过水热法合成了一种新的一维链状配位聚合物[Gd(3-HPYA)3(H2O)]n(1),其结构经IR,热重分析,元素分析和x-射衍单晶衍射仪表征.1属于三斜晶系,空间群P-1,晶胞参数为:a=0.61943(15)nm,b=1.27000(3)nm,c=1.563 40(4)nm,α=111.728(4)°,β=90.330(4)°,γ=95.202(4)°,Z=2.1通过分子间的氢键堆积为三维网状结构.对1的热稳定性进行了研究.     

(HAlNH)n(n=2～3)环状化合物的结构特征

用自洽场理论(HF)和密度泛函理论(DFT)的B3LYP方法,在6-31G*的水平上对化合物(HAlNH)2和(HAlNH)3的几何结构进行优化,并分别与环丁二烯C4H4和苯分子C6H6的结构和成键方式进行比较.以B3LYP/STO-3G方法讨论其分子轨道波函数(ψ).结果表明C4H4和(HAlNH)2均为D2h对称,前者为长方形结构,形成两个孤立的π键;而后者为菱形结构,形成一个π44键.C6H6和(HAlNH)3分子点群分别为D6h和D3h,并均形成一个π66键.成键原子对分子轨道的贡献不同,其中C原子是完全等价的,而Al和N原子各不相同,N原子比Al的贡献要大得多.     

Computational design and structure-property relationship studies on (I2GaN3) n (n = 1–4) clusters

To look for the single-source precursors, density functional theory calculations were performed to study structures, IR spectra, and stabilities of the possible isomers for the clusters (I₂GaN₃) _n (n = 1–4). It is found that the optimized (I₂GaN₃) _n (n = 2–4) clusters all possess cyclic structure containing Ga-N_α-Ga linkages, and azido group in azides has linear structure. Trends in geometrical parameters with the oligomerization degree n are discussed. The IR spectra are obtained and assigned by vibrational analysis. Thermodynamic properties are linearly correlated with the oligomerization degree n as well as the temperature. Mean-while, the oligomerizations can occur spontaneously at 298.2 K.     

一维梯状配合物{[Cu2(4,4''-bpy)3(p-Ab)2(H2O)2]·(NO3)2·4H2O}n的晶体结构

合成了一维分子梯状配合物{[Cu2(4,4'-bpy)3(p-Ab)2(H2O)2]·(NO3) 2·4H2O}n(4,4'-bpy=4,4'-联吡啶,p-Ab-=对氨基苯甲酸根离子),该配合物晶体属单斜晶系,P2(1)/c空间群,晶胞参数:a=1.110 7(5) nm,b=1.550 4(3) nm,c=1.450 9(3) nm,β=104.81(3)°,V=2.415 5(12) nm3,Z=2.铜离子周围有3个氧原子和3个氮原子与之配位,其中2个氧原子由对氨基苯甲酸的螯合氧原子提供,另一个氧原子由配位水提供,3个氮原子分别由三个4,4'-联吡啶提供.这六个原子在铜离子周围形成一个畸变的八面体配位环境.配体对氨基苯甲酸只有一种配位形式--双齿螯合,第二配体4,4'-联吡啶的两个氮原子均参与配位,将配合物组装成一维分子梯结构.     

[Pb(3-HPYA)2]n的合成及其晶体结构

3-(3-吡啶基)丙烯酸(3-HPYA)配体与过渡金属离子铅通过水热法合成了一种新的三维配位聚合物[Pb(3-HPYA)2]n(1),其结构经IR,元素分析和X-射线单晶衍射仪表征.1属于单斜晶系,空间群P2/c,晶胞参数:a=1.032 3(3)nm,b=1.6944(5)nm,c=0.864 9(3)nm,β=93.939(5)°,Z=1.509 2(8)nm3,Z=4,Mr=490.73,Dc=2.216 g·cm-3,F(000)=9444,μ=11.200.     

H_(3+n)[AsMo_(12-n)V_nO_(40)]·9H_2O(n=2—4)的结构

X光晶体结构分析证实H_(3+n)[AsMo_(12-n)V_+nO_(40)]·9H_2)(n=2—4)的晶体同构,空间群为P,Z=2。n=2时,a=13.951(5),b=14.137(5),c=13.556(4),α=112.44(2),β=109.49(3),γ=60.77(3)°,V=2120.2,M_r=1943.36,D_c=3.044g.cm~(-3),μ=40.90cm~(-1),F(000)=1828。用6216个I>3σ(I)的独立衍射精修结构,R=0.082;n=3时,a=13.891(7),b=14.076(5),c=13.483(5)A,α=112.34(3),α=109.26(3),γ=60.82(3)°,V=2094.5,M_r=1899.37,D_c=3.011g.cm~(-3),μ=40.63cm~(-1),F(000)=1792。用6699个I>3σ(I)的独立衍射精修结构,R=0.054;n=4时,a=13.854(3),b=14.099(2),c=13.501(4),α=112.09(2),β=109.13(2),γ=61.03(2)°,V=2103.0,M_r=1855.38,D_c=2.92(悬浮法),D_c=2.930g.cm~(-3),μ=39.71cm~(-1),F(000)=1756。用7613个I>3σ(I)的独立衍射精修结构,R=0.044。实验采用MoKα辐射,λ=0.71073,T=296K。杂多阴离子均呈准Keggin结构,12个金属原子呈无序分布,可以M(Mo/V)表示。AsO_4四面体中As—O键长1.66—1.68,O—As—O键角均在109.5°左右。畸变的MO_6八面体中,M—O键长分布在1.63—2.36范围。水分子无序处在晶胞中十四个位置上,除O_w(12)和O_w(13)外的水分子均与杂多阴离子形成氢键,且水分子间形成如沸石中那样的复杂?     

New hybrid layered molybdates based on (2/∞)[Mo(n)O(3n+1)]2- units (n = 7, 9) with systematic organic-inorganic interfaces

Two new hybrid organic-inorganic molybdates based on layered (2/∞)[Mo(n)O(3n+1)](2-) blocks and organoammonium cations (+)(Me(x)H(3-x)N)(CH(2))(6)(NH(3-x)Me(x))(+) (x = 0-1), namely, (H(3)N(CH(2))(6)NH(3))[Mo(7)O(22)]·H(2)O (1) and (MeH(2)N(CH(2))(6)NH(2)Me)[Mo(9)O(28)] (2), have been synthesized under hydrothermal conditions. The (2/∞)[Mo(9)O(28)](2-) unit in 2 is an unprecedented member of the (2/∞)[Mo(n)O(3n+1)](2-) family with the n value extended to 9. The structural filiation between the (2/∞)[Mo(n)O(3n+1)](2-) (n = 5, 7, 9) blocks is well established, and their structural similarity with the (2/∞)[MoO(3)] slabs in α-MoO(3) is also discussed. Single-crystal X-ray analyses show that the (2/∞)[Mo(n)O(3n+1)](2-) layers in 1 and 2 are pillared in the three-dimensional networks by the organic cations with a similar connection at the organic-inorganic interface. In addition, a correlation between the topology of the (2/∞)[Mo(n)O(3n+1)](2-) blocks in 1 and 2 and the overall sizes of the associated organic cations is pointed out. Finally, the efficiency of Fourier transform Raman spectroscopy to easily discriminate the different (2/∞)[Mo(n)O(3n+1)](2-) blocks (n = 5, 7, 9) in hybrid organic-inorganic layered molybdate materials is clearly evidenced.     

A three-dimensional porous metal-organic framework based on 9,9-dimethylfluorene-2,7-dicarboxylic acid (H2MFDA): {[Tb2(MFDA)3(DMF)2(H2O)3] · (H2O)3(DMF)6} n

The title metal-organic framework, [Tb₂(MFDA)₃(DMF)₂(H₂O)₃] · (H₂O)₃(DMF)₆} _n (I) (H₂MFDA = 9,9-dimethylfluorene-2,7-dicarboxylic acid, DMF = N,N-dimethylformamide), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction (CIF file CCDC no. 995892). Complex I crystallizes in triclinic space group \(P\bar 1\) with a = 13.0022(3), b = 13.3793(3), c = 25.8929(4) Å, α = 84.060(2)°, β = 88.104(2)°, γ = 66.361(2)°, V = 4104.05(15) ų, C₇₅H₁₀₄N₈O₂₆Tb₂, M = 1851.50, ρ _c = 1.498 g/cm³, μ(MoK _α) = 1.790 mm^?1, F(000) = 1896, GOF = 1.055, Z = 2, the final R ₁ = 0.0522 and wR ₂ = 0.1380 for I > 2σ(I). In MOF I, the Tb₂ dinuclear units double-bridged by two carboxylate groups are connected together by MFDA ligands to give rise to a 3D architecture that consists in two types of 1D open channels along the y axis with about 6 × 8 and 9 × 12 Ų dimensions. The solvent accessible space for the desolvated I is 53.4% of the total volume. The 3D structure can also be rationalized as a six-connected (3.4¹¹.5².6) topological network by considering the Tb₂ dinuclear units as six-connected nodes and MFDA ligands as linkers, respectively.     

Valence of elements in HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4)

HgBa2Can-1CunO2n+2+( (n=1, 2, 3, 4) 1 are tetragonal with space group space P4/mmm. For n=1,2,3, nearly single-phase crystals were obtained, while for n=4, the sample was primarily a mixture of the n=3 and 4 phases. These materials also possessed the highest Tc values yet observed for any superconductors. In this paper, the valences of elements in the title compounds were calculated from bond valence sum method 2. The calculated bond covalency, valences of elements were summarized in Table …