Tb3+/Eu3+镧系金属有机框架材料在荧光检测的研究进展

镧系金属有机骨框架（Lanthanide metal organic frameworks,Ln-MOFs）是以镧系离子为中心,与配体有机物组合的多孔材料,具有良好的光学性质,在许多领域有广泛的应用。不同的镧系离子与相应的有机配体结合,可组成不同性能的Ln-MOFs。在众多镧系元素中,Tb3+和Eu3+是良好的发光中心,常被用于组建发光Ln-MOFs。由Tb3+/Eu3+与有机配体形成的Ln-MOFs具有独特的荧光特性、较大stokes位移以及长发光寿命等优点在荧光检测领域具有重要应用。本文综述了基于Tb3+/Eu3+的Ln-MOFs在离子检测、生物标志物检测以及小分子检测领域的研究进展,对Ln-MOFs的发展前景进行了展望。     

镧系金属有机配合物研究LX: 含碳、氮稀土金属σ键的稀土金属有机配合物的合成和表征

双(2-甲氧乙基环戊二烯基)氯化镧或氯化镱, 在四氢呋喃中, -20℃下,分别与苯乙炔基钠发生交换反应, 生成双(2-甲氧乙基环戊二烯基)苯乙炔基镧或镱, 产率分别为77%和66%。直接将无水三氯化镱或三氯化钇, 在四氢呋喃中, 冰水冷却下, 与两摩尔的双(三甲基甲硅烷基)氨基锂和2-甲氧乙基环戊二烯基钠进行一锅煮反应, 可得2-甲氧乙基环戊二烯基双(双三甲基甲硅烷基氨基)镱或钇, 产率分别为56%和72%。配合物经元素分析, 红外光谱, 核磁共振氢谱和质谱的鉴定, 它们可能是非溶剂化的, 含分子内配位键的中性单体配合物。     

镧系金属有机配合物的研究 XL.双(2-甲氧乙基环戊二烯基)钇和镱的硼氢配合物的合成及晶体结构

双(2-甲氧乙基环戊二烯基>氯化钇和镱,在THF中,室温与硼氢化钠发生置换反应,生成双(2-甲氧乙基环戊二烯基)硼氢化钇(1)和镱(2),产率分别为70和59%.它们都经红外光谱,质谱,~1HNMR和元素分析鉴定.将l和2在THF-已烷中重结晶,得到适用于X射线衍射分析的单晶.1的空间群为Pna2_1,晶胞参数:a=1.2390(3),b=1.1339(2),c=1.1919(2)nm,晶胞体积,1.6745(6)nm~3.D_o=1.39g·om~3,z=4,R=0.061;2的空间群为Pna2_1,晶胞参数:a=1.2399(6),b=1.1371(5),c=1.1897(2)nm,晶胞体积,1.6773(1)nm~3,D_c=1.72g·cm~(-3),z=4,R=0.038,1与2都是含有两个内配位键(Ln—O)的双齿型的单体结构.     

抗早老性痴呆症天然产物石杉碱甲的红外光谱与简正分析——量子化学密度函数理论(DFT)研究

运用量子化学密度函数理论B3LYP/ 6 31G 方法计算了石杉碱甲的电子结构和红外光谱 ,得到了与实验结果的谱图特征基本一致的红外振动光谱 .通过对振动模式的分析 ,指认了 1 0 2个振动模式中分离得比较完全的 45个振动模式 ,结果表明其吡啶酮CO伸缩振动的红外活性最强 ,吡啶酮NH键的伸缩振动的频率最高 .涉及可形成氢键的石杉碱甲氨基氢及吡啶酮内酰胺氢的红外振动吸收的理论值与实验值差异较大 ,其原因是在晶体中存在分子间氢键 ,这不仅改变了这些氢在空间的取向 ,而且也改变了键的力学性质 ,导致红外振动吸收频率发生改变     

有机镧系金属络合物的研究(L)——Cp_2′SmI和Cp′SmI_2·2THF的合成和晶体结构测定

本文首次合成了含分子内氧杂原子配位的双-(2-甲氧乙基环戊二烯基)碘化钐CP_2′SmI(Ⅰ)(Cp′=CH_3OCH_2CH_2C_5H_4)及四氢呋喃溶剂化的2-甲氧乙基环戊二烯基二碘化钐Cp′SmI_2·2THF(Ⅱ)。络合物(Ⅰ)和(Ⅱ)经元素分析及质谱等鉴定。并得到了它们的单晶。结构研究表明,晶体(Ⅰ)属于P2_12_12_1空间群,晶胞参数:a=11.074(4)(?),b=12.929(9)(?),c=12.269(4)(?),(Ⅰ)中每个钐原子和两个环戊二烯基,二个醚基取代基上的氧原子和一个碘原子配位,形成单体结构,Sm(Ⅲ)的配位数为9。晶胞中含有4个单体分子,晶体(Ⅱ)属于P2_1/c空间群,晶胞参数:a=16.304(6)(?),b=8.335(2)(?),c=16.527(5)(?),β=111.8(1)°。晶体(Ⅱ)中每个钐通过一个环戊二烯基,一个醚基取代基上的氧原子,二个四氢呋喃的氧原子和二个碘原子配位形成单体结构,Sm(Ⅲ)的配位数为8。晶胞含4个单体分子。     

N，N′-二甲基-N，N′-二辛基-3-氧戊二酰胺从盐酸介质中萃取三价镧系金属的研究

以煤油/辛醇(7:3,V/V)为稀释剂,研究N,N′-二甲基-N,N′-二辛基-3-氧戊二酰胺(DMDODGA)从盐酸介质中萃取三价镧系金属的性能及反应机理;考察了水相盐酸浓度、萃取剂浓度及温度对其萃取性能的影响。结果表明分配比在所研究酸度范围内随盐酸浓度的增加先增大后减小;随萃取剂浓度的增加而增大;萃合物的组成为MCl3.2DMDODGA(M=Sm,Gd,Dy)或MCl3.DMDODGA(M=Er,Lu)。萃取过程为放热反应,升高温度不利于萃取。同时计算出了萃取反应的平衡常数及热力学函数。萃合物的红外光谱表明羰基氧、醚氧均与镧系离子配位。     

Substituent effects on the redox potentials of dihydroxybenzenes: theoretical and experimental study

The redox reactions of p-hydroquinone and pyrocatechol undergo a two-proton-two-electron process in aqueous solution. We calculated their redox potentials at the B3LYP/6-311+G(d,p) level, and verified the values by employing cyclic voltammetry experiments. Then we selected seven substituent groups (–F, –Cl, –OH, –COOH, –CN, –NH₂, and –NO₂ groups) to systematically investigate the substituent effect, including the sort, position, and number of the substituent, on the redox potentials of p-hydroquinone and pyrocatechol. The calculated results show that –NH₂ and –OH groups can decrease the redox potentials, while –F, –Cl, –COOH, –CN, and –NO₂ groups increase the potential values of p-hydroquinone and pyrocatechol. The calculations can accurately predict the substituent effects on the redox potentials of pyrocatechol and p-hydroquinone. We would expect that the accurate calculation results for the model systems could be applied in the prediction of electrode potentials of other molecules.     

金属富氮化合物N3MN3(M=Be, Mg, Ca)的量子化学研究

使用密度泛函理论，在B3LYP／6—311＋G^＊水平上，对金属富氮化合物N3MN3（M=Be，Mg，Ca）的两种几何结构进行了理论计算，并对得到的几何结构做了振动频率分析．结果表明，所有几何结构的振动频率都是正的，没有虚频存在，说明这类金属富氮化合物是热力学稳定的，当嵌入金属离子后，M—N之间开始表现出显著的离子性特征，由线形N3某团组成的N3MN3比由三角形N3某团组成的N3MN3更稳定．     

Atomic orbital basis sets for use with effective core potentials

Basis sets developed for use with effective core potentials describe pseudo‐orbitals rather than orbitals. The primitive Gaussian functions and the contraction coefficients in the basis set must therefore both describe the valence region effectively and allow the pseudo‐orbital to be small in the core region. The latter is particularly difficult using 1s primitive functions, which have their maxima at the nucleus. Several methods of choosing contraction coefficients are tried, and it is found that natural orbitals give the best results. The number and optimization of primitive functions are done following Dunning's correlation‐consistent procedure. Optimization of orbital exponents for larger atoms frequently results in coalescence of adjacent exponents; use of orbitals with higher principal quantum number is one alternative. Actinide atoms or ions provide the most difficult cases in that basis sets must be optimized for valence shells of different radial size simultaneously considering correlation energy and spin‐orbit energy. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 516–520, 2000     

Revised model core potentials of s-block elements

We developed new model core potentials (MCPs) for s-block elements from Na to Ra, in which the outer core (n-1)s and (n-1)p electrons are treated explicitly together with the ns electrons. By adding suitable correlating functions, we demonstrated that the present MCP basis sets show excellent performance in describing the electronic structures of atoms and molecules, bringing about accurate ionization potentials of atoms and very good spectroscopic constants of ionic and covalent molecules. The results obtained with the new MCPs are very close to the ones obtained using the all-electron correlation consistent basis sets of Dunning.     

单核和双核钴羰基-亚硝基配合物的理论研究

利用密度泛函理论研究了钴羰基-亚硝基配合物Co(NO)(CO)n (n=1～4) 和Co2(NO)2(CO)n(n=2～5)体系.Co(NO)(CO)n (n=1～4)的低能构型和前人研究的等电子体Ni(CO)n+1类似,并且理论预测还可能存在热力学不稳定的具有弯曲的NO配体的Co(NO)(CO)4.理论预测Co2(NO)2(CO)n (n=2～5)的各不同异构体的构型非常相似,能量也很接近,因此其势能面非常复杂,但是其异构体的构型与前人理论预测的等电子体Ni2(CO)n+2非常类似,即Co2(NO)2(CO)5,Co2(NO)2(CO)4和Co2(NO)2(CO)3分别有1,2和3个桥配体.离解能计算表明,对双核钴化合物,羰基解离将比Co-Co键断裂更容易.     

Generalized relativistic effective core potentials for superheavy elements

The generalized relativistic effective core potentials (GRECPs) for calculations of electronic structure and physical-chemical properties of compounds containing superheavy elements (Z ≥ 104) are presented. Features of accounting for the finite nuclear size effects which are unusually large for superheavy elements are discussed in details. Accuracy of the GRECPs is analyzed in atomic calculations compared to all-electron studies with the Dirac-Coulomb-Breit Hamiltonian. Applications of the GRECP method in molecular and cluster calculations are surveyed.     

Ab initio calculations on some transition metal heptoxides by using effective core potentials

The ab initio molecular structures and vibrational frequencies for several transition metal heptoxides X₂O₇ⁿ⁻ (n=0, 2, 4) were calculated using effective core potentials at the HF and DFT (B3LYP) levels. The relative merits of different valence basis set arrangements were tested by comparison with experimental results available, in particular with gas-phase Re₂O₇ molecular structure and vibrational frequencies. The calculations were then extended to other heptoxides of the VB, VIB and VIIB transition metal groups. The results indicate that a staggered geometry (either D_3d or C₂) is the energy minimum for most of the heptoxides studied. The only exceptions are Mn₂O₇, which clearly prefers an eclipsed C_2v(syn) configuration, and Tc₂O₇, for which C₂ and C_2v(syn) geometries have nearly the same energy.

Particular attention was given to the magnitude of the X–O–X bond angle, as this structural parameter has been a matter of some controversy. The calculated values range from 125° (Mn₂O₇) to 180° (Group VB heptoxides) and depend on the position of the transition metal in the Periodic Table. A tendency for linearity of the X–O–X moiety on going both downwards the group and backwards the period was observed and discussed.     

Low-temperature biligand complexes of europium and samarium with mesogenic alkylcyanobiphenyls

For low-temperature cocondensates of europium and samarium (M) with a mesogenic ligand 4-pentyl-4-cyanobiphenyl (L), IR and UV spectroscopy studies have revealed the formation of two ML complexes (M/L = 1:2 and 1:1). Model calculations have been carried out in terms of density functional theory using the B3LYP exchange correlation potential. Biligand structures with an antiparallel arrangement of two ligand molecules including one and two metal atoms, respectively, are suggested. The values of the spectral shifts and the relative thermal stability of the complexes are discussed.Original Russian Text Copyright © 2004 by A. V. Vlasov, T. I. Shabatina, S. V. Konyukhov, A. Yu. Ermilov, A. V. Nemukhin, and G. B. SergeevTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 406–411, May–June, 2004.     

苯并噻二唑醇解反应机理的理论研究

苯并噻二唑（BTH）是新型植保制剂。预防对象包括白粉病、锈病、霜霉病等阻引。 为更好地了解BTH的环境行为，本文研究了BTH醇解反应机理及反应的动力学。