[Co(3,3-tri)(amp)Cl]2+四个经式异构体取代、重排反应及其与结构关系的研究

对[Co(3,3-tri)(amp)Cl]²⁺四个几何经式异构体在不同条件下的取代及重排反应进行考察的实验结果表明,四个几何经式异构体碱性环境下的水解速率没有显著的差异,cis异构体比trans异构体约快20倍。实验中没有观察到面式异构体。在100℃二甲亚砜中加热的重排反应实验中可观察到异构体进行配体翻转的历程,如异构体m1-Cl转化为m4-Cl,m2-Cl转化为m3-Cl。m3和m4相对较稳定。利用量子化学从头计算法,在赝势基组RHF/LANL2DZ的水     

[Co(3,3-tri)(amp)Cl]~(2+)四个经式异构体取代、重排反应及其与结构关系的研究

对犤Co(3,3-tri)(amp)Cl犦2+四个几何经式异构体在不同条件下的取代及重排反应进行考察的实验结果表明,四个几何经式异构体碱性环境下的水解速率没有显著的差异,cis异构体比trans异构体约快20倍。实验中没有观察到面式异构体。在100℃二甲亚砜中加热的重排反应实验中可观察到异构体进行配体翻转的历程,如异构体m1-Cl转化为m4-Cl,m2-Cl转化为m3-Cl。m3和m4相对较稳定。利用量子化学从头计算法,在赝势基组RHF/LANL2DZ的水平上对该体系各异构体进行了基态能量、几何优化的计算,与已测定的异构体m3犤ZnCl4犦H2O和m4犤ZnCl4犦晶体结构参数比较,键长及键角的相对误差不超过3%。根据各异构体基态能量说明了各异构体的平衡分布;讨论了键角变形性大小与各异构体反应性大小的关系。     

[Co(2,3-tri)(amp)Cl]~(2+)几何经式异构体取代与重排规律、构效关系的研究

对[Co（2,3-tri）（amp）Cl]2+四个几何经式异构体在不同条件下的取代及重排反应进行了详细的考察.因二元胺中吡啶环造成的空间拥塞,使cis异构体碱水解速度比trans异构体约快100倍,控制碱水解实验结果表明,每一异构体的水解产物均含四个经式异构体,且具有相同分布.实验过程中未观察到面式异构体.在二甲亚砜中加热的重排反应中,异构体m1表现出最高的反应性,cis异构体均首先转化为trans异构体m3,而后可观察到trans异构体m3与m4的平衡.利用时间分辨核磁共振仪测定了在氘代水里各异构体中各活性氢的氘代化速度.反应活性最低的异构体m4具有氘代速度最快的活性氢,当这些活性氢完全氘代化时仍未见其水解或重排产物;而相同实验条件下异构体m1或m2中相应活性氢的氘代化速度则要缓慢得多,但同时可观察到水解和重排产物.这说明在碱催化水解过程中氘代速度快的活性氢与异构体的反应性并非正比关系,然而活性氢的氘代化是观察到异构体水解重排的必要条件.利用量子化学从头计算法,在赝势基组RHF/LANL2DZ的水平上对该体系各异构体进行了结构优化计算,与对应异构体的晶体结构参数比较,一般相对误差不超过3％.从能量角度来看,cis异构体比trans异构体高出约4kJ/mol,而面式异构体则至少比经式异构体高约17kJ/mol;考虑溶剂化     

[Co(2,3-tri)(amp)Cl]^2^+几何经式异构体取代与重排规律、构效关系的研究

对[Co(2,3-tri)(amp)Cl]^2^+四个几何经式异构体在不同条件下的取代及重排反应进行了详细的考察。因二元胺中吡啶环造成的空间拥塞,使cis异构体碱水解速度比trans异构体约快100倍,控制碱水解实验结果表明,每一异构体的水解产物均含四个经式异构体,且具有相同分布。实验过程中未观察到面式异构体。在二甲亚砜中加热的重排反应中,异构体m1表现出最高的反应性,cis异构体均首先转化为trans异构体m3,而后可观察到trans异构体m3与m4的平衡。利用时间分辨核磁共振仪测定了氘代水里各异构体中各活性氢的氘代化速度。反应活性最低的异构体m4具有氘代速度最快的活性氢,当这些活性氢完全氘代化时仍未见其水解或重排产物;而相同实验条件下异构体m1或m2中相应活性氢的氘代化速度则要缓慢得多,但同时可观察到水解和重排产物。这说明在碱催化水解过程中氘代速度快的活性氢与异构体的反应性并非正比关系,然而活性氢的氘代化是观察到异构体水解重排的必要条件。利用量子化学从头计算法在赝势基组RHF/LANL2DZ的水平上对该体系各异构体进行了结构优化计算,与对应异构体的晶体结构参数比较,一般相对误差不超过3%,从能量角度来看,cis异构体比trans异构体高出约4kJ/mol,而面式异构体则至少比经式异构体高约17kJ/mol;考虑溶剂化影响,一般约低5kJ/mol。考察结构参数结果显示,结构变形性参数能较好地解释异构体反应活性。     

[Co(2,3-tri)(amp)Cl]ZnCl4体系中三个几何经式异构体的识别

对[Co(2,3 -tri) (amp) Cl] ZnCl42, 3 - tri= N - (2 - aminoethyl) - 1,3 - propanediamine; amp ＝ 2 - (aminomethyl)pyridine)体系进行了合成,分离出四个配合物.用单晶X射线衍射分析了两个结构,用二维核磁共振DQCOSY和NOESY技术联合解析了另一结构.结构解析显示它们为该体系的四个几何经式异构体(meridian isomers).两个晶体结构都属中心对称的空间群,表明它们都是外消旋的对映体.     

[GeCN2]分子异构化势能面的理论研究

在CCSD(T)/6-311＋G(2df)//B3LYP/6-311＋G(d)水平下, 研究了四原子分子 [GeCN2]的各个异构体的几何结构、红外振动光谱、相对能量及异构化和解离稳定性, 构建了[GeCN2]势能面. 我们得到了7个[GeCN2]异构体, 包括5个直线型结构GeNCN (1), GeNNC (2), NGeCN (3), NGeNC (4), GeCNN (5)和2个环形结构Ge-cCNN (6)和Ge-cNCN (7). 其中异构体5, 6, 7是我们新找到的构型, 而且GeCNN (5)是整个势能面上稳定性仅次于GeNCN (1)的异构体. 几何和电子结构分析表明, GeCNN (5)具有共轭三键结构: Ge≡C—N≡N:. 由于具有良好的热力学和动力学稳定性, 异构体GeCNN (5)有望在实验中观测到. 我们建议利用过渡金属羰基化合物的络合作用可以进一步稳定GeCNN (5). 本研究为寻找新型含高周期元素的多重键化合物提供了理论线索.     

[Co(2,3-tir)(amp)Cl]ZnCl4体系中三个几何经式异构体的 识别

对[Co(2,3-tir)(amp)Cl]ZnCl42,3-tri=N-(2-aminoethyl)-1,3-propanediamine;amp=2-(aminomethyl)pyridine)体系进行了合成,分离出四个配合物。用单晶X射线衍射分析了两个结构,用二维核磁共振DQCOSY和NOESY技术联合解板了另一结构。结构解析显示它们为该体系的四个几何经式异构体(meridianisomers)。两个晶体结构都属中心对称的空间群,表明它们都是外消旋的对映体。     

[Co(2,3-tir)(amp)Cl]ZnCl4体系中三个几何经式异构体的 识别

对[Co(2,3-tir)(amp)Cl]ZnCl42,3-tri=N-(2-aminoethyl)-1,3-propanediamine;amp=2-(aminomethyl)pyridine)体系进行了合成,分离出四个配合物。用单晶X射线衍射分析了两个结构,用二维核磁共振DQCOSY和NOESY技术联合解板了另一结构。结构解析显示它们为该体系的四个几何经式异构体(meridianisomers)。两个晶体结构都属中心对称的空间群,表明它们都是外消旋的对映体。     

SnCNN: 一个包含SnC三重键的分子

在CCSD(T)//B3LYP方法下, 研究了四原子分子[SnCN₂]的势能面, 发现线性异构体SnCNN具有良好的动力学稳定性. 几何分析与键分析表明, 该异构体包含Sn≡C三重键, 并可以用过渡金属络合物配合稳定来增加其稳定性.     

[Co(2,3-tri)(amp)Cl][ZnCl_4]体系中部分几何经式异构体的结构测定

利用单晶X射线衍射分析了Co23triampClZnCl423tri=N2Aminoethyl13propanediamineamp=2Aminomethylpyridine体系中的一异构体m3Co23triampClZnCl4·2.5H2O结构用二维核磁共振DQCOSY和NOESY技术联合解析了另两个异构体m2Co23triampClZnCl4及m4Co23triampClZnCl4在溶液中的结构。结构解析显示它们为该体系的三个几何经式异构体。解析的晶体结构属中心对称的空间群表明它是外消旋的对映体。     

Tris(tris(trimethylsilyl)silyl)gallium,Ga{Si(Si(CH3)3)3}3

The title compound has been prepared in good yield by the reaction of gallium trichloride with base‐free hypersilyl lithium (Li–Si(SiMe₃)₃, Me = CH₃) in a 1 : 3 molar ratio. Ga(Si(SiMe₃)₃)₃ is monomeric in solution and in the solid state. The compound has been characterized with NMR, IR and Raman techniques as well as by an X‐ray structure determination (planar GaSi₃‐skeleton, monoclinic space group P2₁/c, Z = 4, d(Ga–Si) = 249,8 ± 0,2 pm).     

LiMn3(SeO3)2(HSeO3)6

The title compound, lithium trimanganese bis­[trioxo­selenate(IV)] hexa­kis[hydrogentrioxoselenate(IV)], is built up from a vertex‐sharing network of distorted Mn^IIIO₆ octa­hedra, SeO₃ and HSeO₃ pyramids and unusual Li(OH)₆ octa­hedra, resulting in a dense three‐dimensional structure. Mn, Li and one Se atom have site symmetries of , , and 3, respectively. An O—H⋯O hydrogen bond helps to establish the crystal packing.     

Spectroscopic properties of Er(3+)/Yb(3+) co-doped Bi(2)O(3)-B(2)O(3)-GeO(2) glasses

Er(3+)/Yb(3+) co-doped 60Bi(2)O(3)-(40 - x)B(2)O(3)-xGeO(2) (BBG; x=0, 5, 10, 15 mol%) glasses that are suitable for fiber lasers, amplifiers have been fabricated and characterized. The absorption spectra, emission spectra, and lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition were measured and calculated. With the substitution of GeO(2) for B(2)O(3), both Delta lambda(eff) and sigma(e) decrease from 75 to 71 nm and 9.88 to 8.12 x 10(-21) cm(2), respectively. The measured lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition increase from 1.18 to 1.5 ms and 36.2% to 43.2%, respectively. The emission spectra of Er(3+):(4)I(13/2) --> (4)I(15/2) transition was also analyzed using a peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the (4)I(15/2) and (4)I(13/2) levels of Er(3+) in the BBG glasses. The results indicate that the (4)I(13/2) --> (4)I(15/2) emission of Er(3+) can be exhibit a considerable broadening due to a significant enhance the peak A, and D emission.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(N(CH3)2)3 – OP(CH3)3 und SP(N(CH3)2)3 – SP(CH3)3

Vibrational Spectra and Force Constants of the Series OP(N(CH₃)₂)₃ – OP(CH₃)₃ and SP(N(CH₃)₂)₃ – SP(CH₃)₃ The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy.     

Hyperfine structures of the 2 (3)Sigma(g) (+), 3 (3)Sigma(g) (+), and 4 (3)Sigma(g) (+) states of Na(2)

The hyperfine structures of the 2 (3)Sigma(g) (+), 3 (3)Sigma(g) (+), and 4 (3)Sigma(g) (+) states of Na(2) have been resolved with sub-Doppler continuous wave perturbation facilitated optical-optical double resonance spectroscopy via A (1)Sigma(u) (+) approximately b (3)Pi(u) mixed intermediate levels. The hyperfine patterns of these three states are similar. The hyperfine splittings of the low rotational levels are all very close to the case b(betaS) limit. As the rotational quantum number increases, the hyperfine splittings become more complicated and the coupling cases become intermediate between cases b(betaS) and b(beta J) due to spin-rotation interaction. We present a detailed analysis of the hyperfine structures of these three (3)Sigma(g) (+) states, employing both case b(betaS) and b(beta J) coupling basis sets. The results show that the hyperfine splittings of the (3)Sigma(g) (+) states are mainly due to the Fermi-contact interaction. The Fermi contact constants for the two d sigma Rydberg states, the 2 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+), are 245+/-5 MHz and 225+/-5 MHz, respectively, while the Fermi contact constant of the s sigma 3 (3)Sigma(g) (+) Rydberg state is 210+/-5 MHz. The diagonal spin-spin and spin-rotation constants, and nuclear spin-electronic spin dipolar interaction parameters of the 3 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+) states are also obtained.     

Li(VO2)3(TeO3)2

The title compound, lithium tris[dioxidovanadium(V)] bis[trioxidotellurium(IV)], contains chains of edge‐sharing distorted VO₆ octahedra. The pyramidal TeO₃ groups crosslink the chains into sheets. Finally, an Li⁺ cation adopting an unusual capped trigonal–bipyramidal LiO₆ geometry bridges the layers to complete a three‐dimensional structure.     

Interactions in the Quinary System H2O-Y(NO3)3-La(NO3)3-Pr(NO3)3-Nd(NO3)3 to Very High Concentrations

Isopiestic measurements have been carried out for the quinary system H₂O-Y(NO₃)₃-La(NO₃)₃-Pr(NO₃)₃-Nd(NO₃)₃ at 298.15 K to near saturation. The measurements can be represented within experimental uncertainty over the full concentration range by a modified Pitzer ion-interaction model extending to the C ⁽³⁾ term. In addition, the system obeys the Zdanovskii–Stokes–Robinson model or partial ideal solution model within the accuracy of the isopiestic measurements, indicating zero interchange energy between the unlike salts, which is consistent with the nature of trivalent rare-earth elements.     

Bis(trifluoroacetyl) peroxide, CF(3)C(O)OOC(O)CF(3)

Pure, highly explosive CF(3)C(O)OOC(O)CF(3) is prepared for the first time by low-temperature reaction between CF(3)C(O)Cl and Na(2)O(2). At room temperature CF(3)C(O)OOC(O)CF(3) is stable for days in the liquid or gaseous state. The melting point is -37.5 degrees C, and the boiling point is extrapolated to 44 degrees C from the vapor pressure curve log p = -1875/T + 8.92 (p/mbar, T/K). Above room temperature the first-order unimolecular decay into C(2)F(6) + CO(2) occurs with an activation energy of 129 kJ mol(-1). CF(3)C(O)OOC(O)CF(3) is a clean source for CF(3) radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) A and dihedral angle phi(C-O-O-C) = 86.5(32) degrees. The density functional calculations reproduce the experimental structure very well.