蒽醌与稀土离子间的能量转移研究

分子间或分子内的电子激发态能量转移是重要的初级光化学过程，很多体系电子激发态能量转移过程已经报导[1-3]，对稀土离子和谈基化合物的研究发现，用光激发配体时，激发了的配体可将能量转移给稀土离子，使稀土离子激发到发光能级，可观察到稀土的特征荧光，若稀土离子和谈基     

石墨炉原子吸收光谱中GdCl3,Gd（NO3）3基体的背景吸收

研究了石墨炉原子吸收光谱中ＧｄＣｌ３、Ｇｄ（ＮＯ３）３基体的背影吸收影响。背景吸收波长特性的研究表明，ＧｄＣｌ３和Ｇｄ（ＮＯ３）３的背景吸收都具有明显的波长特性。蒸发行为研究表明ＧｄＣｌ３的背景吸收主要来自ＧｄＣｌ３的分子蒸气，Ｇｄ（ＮＯ３）３的背景吸收主要来自ＮＯ。钆基体的背景吸收峰高与灰化有关，ＧｄＣｌ３背上曲线轮廓与原子化温度和原子化方式有关。Ｇｄ（ＮＯ３）３的背景吸收远小于ＧｄＣｌ３。本文     

铋酸盐铒玻璃在1.54 μm处的荧光特性研究

The bismuth glasses with Er3+ and Er3+/Yb3+ co doped were fabricated by the technique of high temperature melting. The absorption and fluorescence spectra, fluorescence lifetime and FWHM were measured. The explanation of concentration quenching in case of high level Er3＋ doped the bismuth glasses is given. The sensitizing of Yb3＋ to Er3＋ in Er3＋/Yb3＋ co doped bismuth glasses is discussed. The explanation of the influence on absorption and fluorescence spectra, fluorescence lifetime and FWHM in case of the change of Er3+ or Yb3+ in bismuth glasses with Er3+/Yb3+ co doped is given. It is found that the change of Er3+ content has obviously influenced the fluorescence lifetime and FWHM while the change of Yb3+ content has remarkably influenced the absorption and fluorescence intensity. The band at around 1.54 μm in Er3+/Yb3+ co doped bismuth glass reaches 76 nm and the fluorescence lifetime is 0.55 ms.     

顺反构型[Rh(NH3)3Cl]在室温水溶液中的行为兼论铂配合物的抗癌机理及药效

In this paper the behaviour of mer-and fac-(Rh(NH3)3Cl3) in aqueous solution at room temperature is reported. The experimental results show that some obvious differences exist between the properties of mer-and fac-(Rh(NH3)3Cl3) coordination compounds in aqueous solution at room temperature. The fac-(Rh(NH3)3Cl3) is relatively stable, and the mer-(Rh(NH3)3 Cl3) is unstable. When one of its Cl^- is replaced by H2O(RH(NH3)3)(OH)2Cl2)Cl is formed. The mechanism of anti-tumour action of platinum compounds is briefly discussed.     

负载型三氧化钼催化剂表面结构和表面酸位的激光Raman光谱研究

测定了MoO3/γ-Al2O3、MoO3/TiO2、MoO3/SiO2的激光Raman谱. 通过MoO3/γ-Al2O3、MoO3/TiO2在吡啶吸附前后、氨水提取前后的谱图对比说明, 单层分散的MoO3, 即特征峰为～950cm^-^1的"二维聚钼酸"中钼的配位状态不是单一的,其中一种表面含钼物种(Mo-1)不吸附吡啶, 不溶于氨水, 不显示较强的表面酸性; 另一种表面含钼物种(Mo-2)可吸附吡啶, 溶于氨水, 与催化剂的表面酸位密切相关. 我们认为Mo-1为四面体配位的钼; Mo-2为八面体配位的钼. MoO3/SiO2中的MoO3能100%被氨水溶去, 其酸位数与表面Mo^6^+数之比接近1, 是由其中Mo-2的比例较高, 载体与活性组分之间的相互作用较弱这两个因素所造成的。     

端基含108个己氧基偶氮苯介晶基元三代树状碳硅烷液晶研究

用发散法合成以四碳硅烷为核心,周边含108个己氧基偶氮苯介晶基元(M3)端基的三代树状碳硅烷(D3)液晶,并用元素分析、核磁共振、激光解吸电离飞行时间质谱、红外光谱、紫外光谱、偏光显微镜、差示扫描量热(DSC)和X射线衍射法(WAXD)进行表征.D3为向列相液晶,与M3相同,三代(D3)、二代(D2)和一代(D1)树状物的相态由介晶基元的相态决定.D3的液晶态相行为是K79N136I132N,D3的熔点比M3的低19℃,D3的清亮点比M3的增加16℃,D3液晶态温区比M3宽35℃.     

(CH~3)~3M/PH~3(M=Ga,In)体系的密度泛函研究

用密度泛函理论方法对Me~3M/PH~3(Me=CH~3,M=Ga,In)体系及相关的一些分子进行了计算,得到优化几何构型、振动基频、电荷分布等参数和可能发生的化学反应的能量。为了比较,对Me~3Ga/NH~3体系也做了相应的研究。计算结果表明反应中间体Me~3M·YH~3(Y=N,P)具有稳定的结构,其生成反应是放热的。Me~3M·YH~3中的M－Y键比较弱,但当它们通过一个放热的分子内反应分解为Me~2MYH~2和CH~4后M－Y键大为增强。根据计算结果讨论了Me~3M/YH~3体系可能的热分解途径。由于Me~3M·YH~3单分子分解反应活化能比Me~3M中的M－C键直接均裂分解所需的能量要低得多,在有YH~3存在的情况下,Me~3M的热分解最有可能是首先形成Me~3M·YH~3及Me~2MYH~2中间体,然后进一步分解。用这一机理可以解释现有的实验事实。     

铋基钙钛矿(CH3NH3)3Bi2I9薄膜的制备及在光伏电池中的应用

铋基钙钛矿由于稳定性强及毒性低,被认为是未来极具发展潜力的环保型钙钛矿材料。(CH₃NH₃)₃Bi₂I₉(MBI)因具有优异的光吸收性能而引起人们的普遍关注。本文介绍了MBI钙钛矿晶体的结构及性能,总结了其薄膜的制备方法,并重点叙述了不同方法制备的MBI钙钛矿薄膜在光伏电池中的应用情况。MBI钙钛矿与铅基钙钛矿的效率相比还有很大差距,如何提高其光电转换效率仍是今后研究的主要方向。     

Quantitative study on La~(3+) influx mediated by sodium-calcium exchanger in human lymphocytes

Whether La3+ can enter human peripheral blood lymphocytes by the Na+/Ca2+ exchanger or not and the effect of La3+on the Na+/Ca2+ exchanger activity are examined by fura-2 technique. And that whether La3+ is sequestered by intracellular organelles (mainly endoplasmic reticulum and mitochondria) is studied by this method. La3+uptake is obviously stimulated by pre-treating the cells with ouabain and by removing extracellular Na+, and intracellular La3+concentration ([La3+]i) is directly proportional to its extracellular concentration ([La3+]o). But when [La3+]o exceeds 0.4 mmol/L, the 340/380 nm ratio of fluorescence is no longer varied and the maximum [La3+], is 1.5×10-12 mol · L-1. The higher concentration of La3+ (0.1 mmol/L) increases Na+/Ca2+ exchange-mediated calcium influx, but lower concentration (10 μmol/L) appears to block calcium influx. The results also suggest that cytosolic La3+ is transported by the ATP-dependent Ca2+ pump. Intracellular Ca2+ stores are depleted by ionomycin, and then ion     

Royal crown-shaped electride Li3-N3-Be containing two superatoms: new knowledge on aromaticity

The structure and aromaticity of a royal crown-shaped molecule Li(3)-N(3)-Be are studied at the CCSD(T)/aug-cc-pVDZ level. This molecule is a charge-separated system and can be denoted as Li(3) (2+)N(3) (3-)Be(+). It is found that the Li(3) (2+) ring exhibits aromaticity mainly because the Li(3) (2+) ring can share the pi-electron with the N(3) (-3) ring. The 4n+2 electron counter rule can be satisfied for the Li(3) (2+) subunit if the shared pi valence electron of N(3) (3-) subunit is also taken into account. This new knowledge on aromaticity of a ring from the interactions between subunits is revealed first time in this paper. Li(3)-N(3)-Be can be also regarded as a molecule containing two superatoms (Li(3) and N(3)), which may be named as a "superomolecule." Li(3)-N(3)-Be is a new metal-nonmetal-metal type sandwich complex. The N(3) (3-) trianion in the middle repulses the electron clouds of the two metal subunits (mainly to the Li(3) superatom) to generate an excess electron, and thus Li(3)-N(3)-Be is also an electride. This phenomenon of the repulsion results in: (a) the HOMO energy level increased, (b) the electron cloud in HOMO distended, (c) the area of the negative NICS value extended, and (d) the VIE value lowered. So the superomolecule Li(3)-N(3)-Be is not only a new metal-nonmetal-metal type sandwich complex but also a new type electride, which comes from the interaction between the alkali superatom (Li(3)) and the nonmetal superatom (N(3)).     

WO3在不同担体上的程序升温硫化研究

利用ＴＰＳ方法考察了ＷＯ３在γ－Ａｌ２Ｏ３，ＴｉＯ２－Ａｌ２Ｏ３及活性碳上的硫化过程，结果发现，随着ＷＯ２担载量的增加，表面Ｗ物种硫化峰的数目增加，表明ＷＯ３的的担载量超过一定量后，在这三种担体表面，都有几种Ｗ物种同时存在：ＷＯ３／ＴｉＯ２－Ａｌ２Ｏ３与ＷＯ３／Ａｌ２Ｏ３相比，当ＷＯ３担载量低于一个单层分布时，硫化温度明显降低，而超过一个单层分布后，两者的硫化温度相接近，表明ＴｉＯ２的调变作用对低     

NF3 decomposition over some metal oxides in the absence of water

NF3 decomposition in the absence of water over Al2O3, Fe2O3, Co3O4 and NiO, and transition metal oxides (Fe2O3, Co3O4 and NiO) coated Al2O3 reagents was investigated. The results show that Al2O3 is an active reagent for NF3 decomposition with 100% conversion lasting for 8.5 h at 400 ℃. Fe2O3, Co3O4 and NiO coated Al2O3 reagents are superior to bare Al2O3, and 5%Co3O4/Al2O3 has a high reactivity with NF3 full conversion maintaining for 10.5 h. It is suggested that the presence of transition metal oxide is beneficial to the reactivity of Al2O3, and results in a significant enhancement in the fluorination of Al2O3.     

Bi4(Ti1/3Sn2/3)3O12掺杂BaTiO3基X8R陶瓷微观结构与介电性能

研究了Bi4(Ti1/3Sn2/3)3O12掺杂对钛酸钡基陶瓷微观结构和介电性能影响。结果表明,掺杂Bi4(Ti1/3Sn2/3)3O12后钛酸钡基陶瓷晶粒明显长大,同时烧结温度可由1 280℃降低至1 180℃。系统的介电性能和Bi4(Ti1/3Sn2/3)3O12的掺杂量有密切关系。当Bi4(Ti1/3Sn2/3)3O12的掺杂量从0.5mol%增加到2mol%,体系的居里峰被明显压低和展宽,当掺杂量为2mol%时居里峰变得不明显。当Bi4(Ti1/3Sn2/3)3O12的掺杂量从0.5mol%增加到2mol%,系统的居里温度由131℃升高至139℃。当Bi4(Ti1/3Sn2/3)3O12的掺杂量为1mol%时,钛酸钡基陶瓷介电常数为1 930,介电常数温度变化率为5%(-55℃),13%(134℃),-8%(150℃),满足X8R标准。     

钙钛矿型复合氧化物LaFeO3和LaCoO3的光催化活性

采用柠檬酸法合成了钙钛矿复合氧化物ＬａＦｅＯ３和ＬａＣｏＯ３,并以其为光催化剂对水溶性染料进行光催化降解实验,研究了不同光源和不同光照时间对降解脱色率的影响。结果表明ＬａＦｅＯ３和ＬａＣｏＯ３均有较强的光催化活性,而ＬａＣｏＯ３的光催化活性明显高于ＬａＦｅＯ３,这主要与Ｆｅ＾３＋和Ｃｏ＾３＋离子的电子构型以及Ｆｅ－Ｏ间和Ｃｏ－Ｏ间的结合能有关。     

(CH_3)_3SiOSO_2CF_3/SbCl_3阳离子引发体系引发1,3-戊二烯聚合

研究了三氟甲基磺酸三甲基硅酯／三氯化锑（（ＣＨ３）３ＳｉＯＳＯ２ＣＦ３／ＳｂＣｌ３）复合引发体系对１,３ 戊二烯的聚合行为．在（ＣＨ３）３ＳｉＯＳＯ２ＣＦ３引发剂中加入ＳｂＣｌ３后,使聚合反应速率提高了２４倍,产率从（ＣＨ３）３ＳｉＯＳＯ２ＣＦ３引发的５５％提高到８０％以上,分子量提高１７倍．在聚合体系中加入酮类后,产率和分子量相对于（ＣＨ３）３ＳｉＯＳＯ２ＣＦ３／ＳｂＣｌ３配比为０２：１时引发所得聚合物均呈下降趋势;但对不同的酮来说,随着酮的位阻的增大,聚合物的产率和分子量均增大．聚合物的１Ｈ ＮＭＲ图和红外谱图数据均证明该聚合反应是通过（ＣＨ３）３ＳｉＯＳＯ２ＣＦ３与体系中残存的水水解所形成的质子酸ＨＯＳＯ２ＣＦ３与ＳｂＣｌ３反应所形成的复合体系引发进行的．     

Yb~(3 )对Tm~(3 )间接敏化与基质晶格关系

Yb3 敏化Tm3 有两种方式 ,一种是直接敏化上转换 ,另一种是间接敏化上转换。前种直接采用 980nm激光激发 ,而后者可用 80 7nm激光激发 ,无疑后者有利于提高上转换发光的量子效率。由于基质晶格的晶体场强度不同 ,对称性有高有低 ,造成的稀土离子的能级分裂不同 ,通过分析双掺BaY2 F8,Cs3Yb2 Cl9等材料的光谱资料并结合生长的双掺Yb3 ,Tm3 ∶ZnWO4 单晶光谱的实际测试与分析 ,提出了Yb3 和Tm3 间的间接敏化共振能量传输的新观点 ,并具体分析了能形成这一上转换机制的条件。与间接敏化非共振能量传输不同 ,一是Yb3 的2 F5/2 →2 F7/2 的跃迁应与Tm3 3H4 →1 G4 能级间隔尽可能接近 ;二是Yb3 激发态能级2 F5/2 与Tm3 的3H4 能级尽可能接近。这要求基质材料的晶体场场强要弱 ,对称性要低。间接敏化共振能量传输极有可能引起光子雪崩上转换 ,这将为探索实用上转换激光晶体提供有益经验。     

Structural stability and electronic state of transition metal trimers

Ground state geometries were searched for transition metal trimers Sc3, Y3, La3, Lu3, Ti3, Zr3, and Hf3 by density functional methods. For all the studied trimers, our calculation indicates that the ground state geometries are either equilateral triangle (Zr3 and Hf3) or near equilateral triangle (Ti3, Sc3, Y3, La3, and Lu3). For rare earth trimers Sc3, Y3, La3, and Lu3, isosceles triangle (near equilateral triangle) at quartet state is the ground state. Isosceles triangle at doublet state is the competitive candidate for the ground state. For Zr3 and Hf3, equilateral triangle at singlet state is the most stable. For Ti3, isosceles triangle (near equilateral triangle) at quintet state gives the ground state. For Sc3, Zr3, and Hf3, where experimental results are available, the predicted geometries are in agreement with experiment in which the ground state is equilateral triangle (Zr3) or fluxional (Sc3 and Hf3). For Y3, the calculated geometry is in agreement with experimental observation and previous theoretical study that Y3 is a bent molecule for the ground state. For La3, our calculation is in excellent agreement with previous theoretical study based on density functional methods.     

New Precursors to 3-Sulfanylhexan-1-ol? Investigating the Keto–Enol Tautomerism of 3-S-Glutathionylhexanal

The volatile thiol compound 3-sulfanylhexan-1-ol (3SH) is a key impact odorant of white wines such as Sauvignon Blanc. 3SH is produced during fermentation by metabolism of non-volatile precursors such as 3-S-gluthathionylhexanal (glut-3SH-al). The biogenesis of 3SH is not fully understood, and the role of glut-3SH-al in this pathway is yet to be elucidated. The aldehyde functional group of glut-3SH-al is known to make this compound more reactive than other precursors to 3SH, and we are reporting for the first time that glut-3SH-al can exist in both keto and enol forms in aqueous solutions. At wine typical pH (~3.5), glut-3SH-al exists predominantly as the enol form. The dominance of the enol form over the keto form has implications in terms of potential consumption/conversion of glut-3SH-al by previously unidentified pathways. Therefore, this work will aid in the further elucidation of the role of glut-3SH-al towards 3SH formation in wine, with significant implications for the study and analysis of analogous compounds.     

An experimental and computational study on the effect of Al(OiPr)3 on atom-transfer radical polymerization and on the catalyst-dormant-chain halogen exchange

Compound Al(OiPr)3 is shown to catalyze the halide-exchange process leading from [Mo(Cp)Cl2(iPrN=CH-CH=NiPr)] and CH3CH(X)COOEt (X=Br, I) to the mixed-halide complexes [Mo(Cp)ClX(iPrN=CH-CH=NiPr)]. On the other hand, no significant acceleration is observed for the related exchange between [MoX3(PMe3)3] (X=Cl, I) and PhCH(Br)CH3, by analogy to a previous report dealing with the Ru(II) complex [RuCl2(PPh3)3]. A DFT computation study, carried out on the model complexes [Mo(Cp)Cl2(PH3)2], [MoCl3(PH3)3], and [RuCl2(PH3)3], and on the model initiators CH3CH(Cl)COOCH3, CH3Cl, and CH3Br, reveals that the 16-electron Ru(II) complex is able to coordinate the organic halide RX in a slightly exothermic process to yield saturated, diamagnetic [RuCl2(PH3)3(RX)] adducts. The 15-electron [MoCl3(PH3)3] complex is equally capable of forming an adduct, that is, the 17-electron [MoCl3(PH3)3(CH3Cl)] complex with a spin doublet configuration, although the process is endothermic, because it requires an energetically costly electron-pairing process. The interaction between the 17-electron [Mo(Cp)Cl2(PH3)2] complex and CH3Cl, on the other hand, is repulsive and does not lead to a stable 19-electron adduct. The [RuCl2(PH3)3(CH3X)] system leads to an isomeric complex [RuClX(PH3)3(CH3Cl)] by internal nucleophilic substitution at the carbon atom. The transition state of this process for X=Cl (degenerate exchange) is located at lower energy than the transition state required for halogen-atom transfer leading to [RuCl3(PH3)3] and the free radical CH3. On the basis of these results, the uncatalyzed halide exchange is interpreted as the result of a competitive S(N)i process, whose feasibility depends on the electronic configuration of the transition-metal complex. The catalytic action of Al(OiPr)3 on atom-transfer radical polymerization (and on halide exchange for the 17-electron half-sandwich Mo(III) complex) results from a more favorable Lewis acid-base interaction with the oxidized metal complex, in which the transferred halogen atom is bound to a more electropositive element. This conclusion derives from DFT studies of the model [Al(OCH3)3]n (n=1,2,3,4) compounds, and on the interaction of Al(OCH3)3 with CH3Cl and with the [Mo(Cp)Cl3(PH3)2] and [RuCl3(PH3)3] complexes.     

Fe3O4@SiO2@YF3∶Eu3+磁-光双功能复合粒子的制备与性能

采用水热法合成了Fe3O4@SiO2@YF3∶Eu3+磁-光双功能复合粒子,对其结构和性能进行了表征。XRD分析表明:Fe3O4表面包覆上了结晶良好的正交晶系的YF3。TEM照片表明:复合粒子为球形,构成核的Fe3O4颗粒的尺寸在200～350 nm之间,Fe3O4@SiO2@YF3∶Eu3+核壳结构复合粒子的尺寸约为230～380 nm,与包覆前的Fe3O4相比较,包覆后,颗粒尺寸增大,并且YF3∶Eu3+是以棒状结构连接在Fe3O4球型颗粒的表面。磁性和荧光光谱分析表明:该复合颗粒同时具有良好的发光性和磁性,使其在生物医学领域具有潜在的应用。