复合物Mg＋-NCSCH3, Ca＋-NCSCH3光解离光谱研究

研究了复合物Mg^＋-NCSCH₃在230～440 nm波段和Ca^＋-NCSCH₃在320～560 nm波段的光解离光谱. 复合物Mg^＋-NCSCH₃, Ca^＋-NCSCH₃光诱导反应的产物质谱表明有非反应猝灭产物Mg^＋(Ca^＋), C—S键断裂产物Mg^＋(Ca^＋)NC 和Mg^＋(Ca^＋)NCS以及重排反应产物Mg^＋(Ca^＋)-CHSH通道. 在原子跃迁谱线(3²S→3²P, 对于Mg^＋; 4²S?4²P, 对于Ca^＋)的红和蓝两边, Mg^＋-NCSCH₃的光解离光谱由两个宽峰组成; 而对于Ca^＋-NCSCH₃, 则是由三个谱峰构成. CIS/6-311＋＋G^**等级上, 对应于基态构型的Mg^＋-NCSCH₃电子态跃迁能量和振子强度与实验光谱较为一致; 而Ca^＋-NCSCH₃有较大的差别. 这是因为CIS方法忽略电子相关效应, 而Ca^＋-based的跃迁中3d和4s轨道间存在较强的混合所致.     

复合物Mg+-NCSCH3光诱导反应

观察了复合物Mg⁺-NCSCH₃在230~440 nm范围的光解离光谱. 在此波段内的复合物光诱导产物的质谱显示, 存在着非反应猝灭产物Mg⁺和反应产物Mg⁺NC、Mg⁺NCS. 反应产物来源于S－C化学键的断裂. 复合物的光解离光谱由两个对应于原子Mg⁺(3²P←3²S)跃迁的宽峰构成. 由量化计算中的CIS方法所获得的吸收谱理论值与实验值吻合较好.     

内含式化合物X@Al12P12的结构与稳定性研究

采用B3LYP/6-31G*方法, 对内含式化合物X@Al₁₂P₁₂ (X＝Li^0/＋, Na^0/＋, K^0/＋, Be^0/2＋, Mg^0/2＋, Ca^0/2＋, H和He)的不同对称性构型进行计算, 讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、频率、HOMO-LUMO能隙和自旋密度．发现X@Al₁₂P₁₂化合物中, 客体X＝Na^0/＋, K^0/＋, Mg和He几乎处在笼的中心, Be和Ca^0/2＋处在中心附近0.033 nm的半径内, Li^0/＋, Be^2＋, Mg^2＋和H很大程度上偏离笼的中心位置. 大部分金属内含式化合物的C₃对称性构型稳定．Li^0/＋, Be^0/2＋, Mg^2＋, Ca^2＋和H与其它离子相比更易嵌入笼内形成稳定的内含式化合物.     

298.16 K Na＋, K＋, Mg2＋//Cl－, NO3－-H2O五元体系的相平衡研究

采用等温溶解平衡法研究了五元体系Na^＋, K^＋, Mg^2＋//Cl^－, NO₃^－-H₂O在298.16 K、氯化钠饱和时各盐的溶解度和饱和溶液的物化性质(密度, 电导率)以及四元体系Na^＋, Mg^2＋//Cl^－, NO₃^－-H₂O的相平衡关系. 研究表明: 在298.16 K, 氯化钠饱和时该五元体系溶解度相图由六个结晶区、九条单变量溶解度曲线和四个零变量点构成, 六个结晶区分别对应于NaNO₃＋NaCl, KNO₃＋NaCl, KCl＋NaCl, Mg(NO₃)₂•6H₂O＋NaCl, MgCl₂•6H₂O＋NaCl和复盐KCl•MgCl₂•6H₂O＋NaCl; 在298.16 K时, 该四元体系的相图由四个结晶区、五条单变量溶解度曲线和二个零变量点构成, 四个结晶区分别对应于NaNO₃, NaCl, Mg(NO₃)₂•6H₂O, MgCl₂•6H₂O.     

多组态二级微扰理论计算CH3O2激发光谱以及CH3O2→CH3＋O2解离反应

在C_s对称性和aug-cc-pVTZ基组水平下, 采用全活化空间自洽场方法(CASSCF)研究了CH₃O₂自由基基态及其阴阳离子的12个低激发态. 为了进一步考虑动态电子相关效应, 采用二级多组态微扰理论(CASPT2)获得更加精确的能量值. 所有计算得到的电子态都是价电子态, 而且所得绝热激发能和电子亲和势与实验值非常接近.在CASPT2//CASSCF理论水平下计算了CH₃O₂从²A"和²A'电子态的CH₃O₂→CH₃＋O₂的解离反应的势能曲线(PECs). 优化得到的裂解产物的几何结构和能量与分别优化CH₃和O₂得到的结果进行比较, 从而确定裂解产物的电子态. 结果表明, 从²A"和²A'电子态的解离反应分别对应产物CH₃(²A")＋O₂(³A")和CH₃(²A")＋O₂(¹A").     

复合物Mg+-S2(CH3)2的光诱导反应

研究了230~440 nm波段复合物Mg+-S2(CH3)2的单光子光诱导反应. 复合物光诱导产物的质谱揭示, 存在着非反应猝灭产物Mg+和反应产物Mg+SCH3. 复合物的光解离光谱由三个对应于离子Mg+(32P←32S)跃迁的宽谱峰构成. 用量化计算中的CIS方法所得的吸收谱理论值与实验值吻合较好.     

[Pb2(TNR)(NO3)2(H2O)]的制备和晶体结构研究

[Pb₂(TNR)(NO₃)₂(H₂O)] was prepared by reaction of the aqueous solution of lead nitrate and magnesium styphnate. The crystal structure of Pb₂(TNR)(NO₃)₂(H₂O)was determined by single crystal diffraction analysis. The crystal is triclinic, space group P1 with crystal parameters a=0.7279(2)nm,b=1.0698(2)nm,c=1.0738(2)nm;α=86.82(1)°,β=89.52(2)°,γ=83.50(2)°;V=0.8295(3)nm³,Z=2,D_c=3.201g·cm^-3, F(000)=716. The final R value is 0.0358.In the crystal structure, one lead ion was represented by nine coor-dination geometry; the other was showed as ten coordination geometry.     

Ca+-叔丁胺络合物的激光诱导反应

使用反射式飞行时间质谱仪, 研究了Ca⁺-叔丁胺络合物在激光诱导下的反应. 得到了反应的光解谱和作为波长函数的光解行为光谱以及各反应通道的分支比. 反应有两个通道, Ca⁺-与分子的解离通道和生成产物Ca⁺-NH₂的反应通道, Ca⁺-是主要产物, 而且在整个激光扫描的范围都存在, 并且在530～595 nm波段是唯一的产物. 反应的光解行为光谱显示出明显的无结构的峰, 分别对应于络合物的跃迁. 结合反应通道的分支比以及量化计算, 对这些峰进行了指认, 并初步探讨了反应的动力学机理.     

发光颜色可调的白磷钙矿结构Ca8MgBi(PO4)7∶Ce3+，Tb3+荧光粉的制备、发光性能及能量传递

采用具有白磷钙矿结构的磷酸盐作为目标产物,通过高温固相法制备了发光颜色可调的 Ca₈MgBi(PO₄)₇∶Ce³⁺,Tb³⁺荧光粉。利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和荧光光谱等表征手段对其物相组成、微观形貌及发光性能进行了详细研究。结果表明：掺杂少量的 Ce³⁺、Tb³⁺并没有改变 Ca₈MgBi(PO₄)₇基质的晶体结构。荧光光谱和荧光寿命曲线确定了 Ce³⁺-Tb³⁺之间存在能量传递,其能量传递机制为四极-四极相互作用,能量传递效率可达 81%。固定 Ce³⁺浓度而逐渐增加 Tb³⁺的掺杂量时,系列Ca₈MgBi(PO₄)₇∶0.08Ce³⁺,yTb³⁺荧光粉的发光颜色可由蓝光调至绿光,从而实现发光颜色的可控化。     

簇合物Co3(CO)7(μ3-S)[μ,η2-CNP(S)(C6H4OCH3)OC(Ph)CH]和Co3(CO)7(μ3-S)[μ,η2-SCNC(CH3)2P(S)(Cl)N(Ph)]的合成与晶体结构

用Co₂(CO)₈分别与两个杂环配体C(S)NHP(S)(C₆H₄OCH₃)OC(Ph)CH (L₁)和C(S)NHC(CH₃)₂P(S)(Cl)N(Ph) (L₂)反应,合成两个新的三核钴羰基硫簇合物Co₃(CO)₇(μ₃-S)[μ,η²-CNP(S)(C₆H₄OCH₃)OC(Ph)CH](Ⅰ)和Co₃(CO)₇(μ₃-S)[μ,η²-SCNC(CH₃)₂P(S)(Cl)N(Ph)](Ⅱ)。用元素分析,IR, ¹H NMR, ³¹P NMR及MS谱表征了它们的结构,同时用X射线衍射法测定了它们的晶体分子结构,二者属于三斜晶系,空间群P1,Ⅰ的晶胞参数为:a=0.84768(1)nm,b=1.19049(3)nm,c=1.43639(1)nm,α=86.926(1)°,β=81.601(3)°,γ=88.535(2)°,V=1.4318(5)nm³,Z=2,D_c=1.641g·cm^-3,F(000)=716,μ=1.893mm^-1,R=0.0602,R_w=0.1515。Ⅱ的晶胞参数为:a=1.2050(2)nm,b=1.2448(2)nm,c=0.8951(2)nm,α=97.49(1)°,β=93.552(4)°,γ=108.432(3)°,V=1.2554(3)nm³,Z=2,D_c=1.841g·cm^-3,F(000)=690,μ=2.419mm^-1,R=0.0423,R_w=0.1075。Ⅰ和Ⅱ的分子骨架Co3S为三角锥构型,S作为面桥基配体,所有CO作为端基配体与三个Co原子成键。Ⅰ中含有CoCoCN四元环组件,Ⅱ中含有CoCoSCN五元环组件。     

The electronic structure of CrO3+ and MoO3+ complexes

The results of ab initio molecular orbital calculations for [CrOf_s]^2? and polarised single crystal electronic spectra of [MoOCl₃(Op(NMe₂)₃)₂] and Ph₄As[MoOCl₄(H₂O)] are presented. These data are consistent with the electronic transitions of the MO³⁺ moieties, O_2pπ → M_dxy and M_dxy → Md_dxy,dyz being the lowest energy transitions in the spectra of their respective complexes, both these transitions being of low intensity.     

Luminescent properties and energy transfer process of Sm3+-Eu3+ co-doped MY2(MoO4)4 (M=Ca,Sr and Ba) red-emitting phosphors

MY₂(MoO₄)₄:Sm³⁺ and MY₂(MoO₄)₄:xSm³⁺,yEu³⁺ (M=Ca, Sr and Ba) phosphors were successfully prepared using solid-state reaction route, and their luminescent properties and energy transfer process from Sm³⁺ to Eu³⁺ were systematically investigated. The results indicate that MY₂(MoO₄)₄:Sm³⁺ phosphors can be effectively excited by 407 nm near UV light originating from the ⁶H_5/2 → ⁴F_7/2 transition of Sm³⁺, and exhibit a satisfactory red emission at 646 nm attributed to the ⁴G_5/2 → ⁶H_9/2 transition of Sm³⁺, in which the emission intensity of SrY₂(MoO₄)₄:Sm³⁺ is the strongest among the MY₂(MoO₄)₄:Sm³⁺ (M=Ca, Sr and Ba) phosphors. For Eu³⁺ co-doped MY₂(MoO₄)₄:Sm³⁺ samples, with increasing Eu³⁺ doping content, the main emission peaks of Sm³⁺ (approximately 646 nm) are decreased, but the emission peaks and intensity of Eu³⁺ are increased while the maximum intensity of luminescence at the Eu³⁺ concentration 0.9. The introduction of Eu³⁺ in the MY₂(MoO₄)₄:Sm³⁺ phosphors can remarkably generate a strong emission line at 616 nm, originating from the ⁵D₀→⁷F₂ transition of Eu³⁺ and Sm³⁺ (⁴G_5/2) → Eu³⁺ (⁵D₀) effective energy transfer process. The energy transfer mechanism from Sm³⁺ to Eu³⁺ was discussed in detail.     

Microwave synthesis and characterization of europium complexes with cinnamic acid and phenanthroline

We report here the synthesis and characterization of a host of Eu(Phen)L₃ with cinnamic acid (C₆H₅CH = CHCOOH, HL) and phenanthroline (Phen), and employing microwave radiation, where the microwave radiation is used just for the uniform heating of the reaction mixture. Its IR absorption spectra, scanning electron microscopy (SEM), and fluorescence spectra were studied. The results show that the particles of Eu(Phen)L₃ phosphors are basically spherical in shape, with good dispersing. The mean particle size is 1–2 μm. The excitation spectrum is a broad band and the main peak is at 320.0 nm. Moreover, excitation peak at 396.0 nm was found in the excitation spectrum. The emission spectrum shows that Eu(Phen)L₃ has narrow emission peaks. The emission peaks are ascribed to Eu³⁺ ions transition from ⁵ D _J (J = 0) to ⁷ F _J (J = 1, 2, 4). However, the strongest main emission peak locates at 614.0 nm, which corresponds to the electric dipole transition of Eu³⁺(⁵ D ₀ → ⁷ F ₂) The article is published in the original.     

Excitation-dependent variation in local symmetry in Ba2Mg(BO3)2 evidenced by Eu3+ luminescent structural probe

Eu³⁺ luminescence was studied in Ba₂Mg(BO₃)₂ by selectively substituting at Mg site. The parent host Ba₂Mg(BO₃)₂ and Ba₂Mg_0.9Eu_0.05Li_0.05(BO₃)₂ were synthesized by conventional solid state reaction method. Their isostructural nature was confirmed using powder X-ray diffraction technique. The photoluminescence excitation spectrum of Eu³⁺ exhibited a broad Eu³⁺O²⁻ charge transfer band with a maximum at 253 nm along with other excitation transitions. The emission characteristics of Eu³⁺ were found to be excitation wavelength-dependent. The equally intense magnetic and electric dipole transitions for excitation under longer wavelengths showed the presence of Eu³⁺ at a site with non-inversion symmetry. Excitation using 253 nm resulted in the predominant magnetic dipole transition revealing Eu³⁺ at a site with inversion symmetry. The difference in the relative intensities of magnetic and electric dipole transitions originates from the change in symmetry around Eu³⁺ in Ba₂Mg(BO₃)₂ under different excitations.     

Synthesis and Photoluminescence Properties of the Red‐Emitting Phosphor Mg3(BN2)N Doped with Eu2+

Mg₃(BN₂)N was prepared by solid state metathesis reactions and several europium (Eu²⁺) doped samples were prepared to discover novel red‐emitting photoluminescent (PL) materials. It turned out that the undoped and doped samples showed very broad deep‐red photoluminescence ranging from about 500 nm into the near infrared. Due to the similar spectra of the undoped and doped samples and unusually high FWHM values of about 5780 cm^–1 we conclude that the luminescence process originates from defect sites. This was confirmed by decay measurements which show that the decay constants for all samples were in the range of several milliseconds.     

Identification of charge transfer (CT) transition in (Gd,Y)BO3:Eu phosphor under 100-300 nm

A broad excitation band in an excitation spectrum of (Gd,Y)BO₃:Eu was observed in the VUV region. It could be considered that this band was composed of two bands at about 160 and 166 nm. The preceding band was assigned to the BO₃ group absorption. The later one at about 166 nm could be assigned to the charge transfer (CT) transition of Gd³⁺-O²⁻. Such an assignment was deduced from the result that broadbands at around 170 nm for GdAlO₃:Eu, and at 183 nm for Gd₂SiO₅:Eu are due to the CT transition of Gd³⁺-O²⁻; this was also identified by CaZr (BO₃)₂:Eu. Since there are no Gd³⁺ ions in it; a weak band in the VUV region in the excitation spectrum of Ca_0.95ZrEu_0.05(BO₃)₂ was observed. The excitation spectra were overlapped between the CT transition of Gd³⁺-O²⁻ and BO₃ group absorption, and it caused the emission of Eu³⁺ effectively in the trivalent europium-doped (Gd,Y)BO₃ host lattice under 147 nm excitation. Intense broad excitation bands were observed at about 155 nm for YBO₃:Eu and at about 153 nm for YAlO₃:Eu; it could be attributed to the CT transition between Y³⁺ and O²⁻. As a result, under the xenon discharge (147 nm) excitation, the intense emission of Eu³⁺ in GdBO₃ was found to be more convenient just because of the partial substitution of Y³⁺ for Gd³⁺.     

Solvation of Calcium–Phosphate Headgroup Complexes at the DPPC/Aqueous Interface

The effects of sodium (Na⁺) and calcium (Ca²⁺) cations on model zwitterionic dipalmitoylphosphatidylcholine (DPPC) monolayers spread on metal chloride salt solutions are investigated by means of vibrational sum frequency generation (VSFG) and heterodyne‐detected (HD)‐VSFG spectroscopy. VSFG and HD‐VSFG spectra in the OH stretching region reveal cation‐specific effects on the interfacial water′s H‐bonding network, knowledge of which has been limited to date. It is found that low‐concentrated Ca²⁺ more strongly perturbs interfacial water organization relative to highly concentrated Na⁺. At higher Ca²⁺ concentrations, the water H‐bonding network at the DPPC/CaCl₂ interface reorganizes and the resulting spectrum closely follows that of the bare air/CaCl₂ interface up to ～3400 cm^?1. Most interesting is the appearance of a negative band at ～3450 cm^?1 in the DPPC/CaCl₂ Im χ_s⁽²⁾ spectra, likely arising from an asymmetric solvation of Ca²⁺–phosphate headgroup complexes. This gives rise to an electric field that orients the net OH transition moments of a subset of OH dipoles toward the bulk solution.     

Computational modeling of environmental plutonyl mono-, di- and tricarbonate complexes with Ca counterions: Structures and spectra: , PuO2(CO3)2Ca, and PuO2(CO3)3Ca3

We have computed the structures, and select vibrational spectra, electron density and molecular orbital contour plots of plutonium(VI) complexes of environmental importance such as [PuO₂(CO₃)₂]²⁻ and [PuO₂(CO₃)₃]⁴⁻. We show that Ca²⁺ is efficacious in gas-phase modeling of electronic and spectroscopic properties of multiply charged plutonyl di and tricarbonate anions through complexes such as PuO₂(CO₃)₂Ca and [PuO₂(CO₃)₃Ca₃]²⁺.     

Darstellung und Charakterisierung der Pentammin-Komplexe [Os(NH3)5(NCS)]2+ und [Os(NH3)5(NCSe)]2+

Preparation and Characterization of the Pentammine Complexes [Os(NH₃)₅(NCS)]²⁺ and [Os(NH₃)₅(NCSe)]²⁺ The new pentammine complexes [Os(NH₃)₅(NCS)]²⁺ and [Os(NH₃)₅(NCSe)]²⁺ are prepared from the reaction of [Os(NH₃)₅(CF₃SO₃)](CF₃ SO₃)₂ with NH₄SCN and KSeCN, respectively, in acetone, and subsequent purification by ion exchange chromatography on carboxymethyl cellulose. Evidence of N-bonding in both cases is given by the vibrational spectra, indicating that Os³⁺ is in terms of Lewis acidity harder than Ru³⁺, Rh³⁺, and Ir³⁺. I.r. and Raman spectra are interpreted according to local C_4v symmetry around Os, and the presumed assignments are confirmed by comparison with the i.r. spectra of the perdeuterated compounds. In the electronic spectra of both complexes charge transfer bands at 412 nm (NCS) and 498 nm (NCSe) are observed, respectively. Further weak absorptions near 4500 and 5100 cm^?1, which are in correlation with electronic Raman bands, are assigned to intraconfigurational transitions within the ²T_2g (O_h) ground term, split into three Kramers doubletts by spin-orbit coupling and lowered symmetry. Electrochemical measurements demonstrate a stabilisation of +III and +II oxidation states by π-back donation to —NCS and —NCSe ligands.     

Effect of Mg2+ Ions on the Stability of PolyA/2PolyU Three-Stranded Helices in Aqueous Solutions

The influence of Mg²⁺, Na⁺ and temperature on the conformational state of three-stranded helical polyA/2polyU (A2U) has been studied by the thermal denaturation method. At Na⁺ concentrations of 0.01–0.1 M , on heating the transition A2U→AU+U (the 3→2 transition) and then AU→A+U transition (the 2→1 transition) are observed. (AU is double helix polyA/polyU; A and U are single-stranded polyA and polyU, respectively.) With 0.01 M and 0.03 M Na⁺ these transitions occur at Mg²⁺ concentrations within (0 ÷ 0.003) M . At these ionic concentrations, there is a narrow temperature region (3 ÷ 5°C) at which double-helical AU formed by the 3→2 transition is resistant to heating. In 0.1 M Na⁺, a rise in the Mg²⁺ concentration leads to a continuous decrease in the temperature range of this region, and above a critical concentration of Mg²⁺ (ca. 3.6×10^–5 M )_cr there is only one transition (the 3→1 transition) instead of the successive transitions 3→2→1. The constants of Mg²⁺ ion association with polyU, polyA and A2U were calculated using equilibrium binding theory. The data obtained helped explain the reasons for the different phase diagrams for A2U + Mg²⁺ complexes in solution at high and low Na⁺ concentrations.