铽与苯乙酮酸、2,2''''-联吡啶、1,10-菲口罗啉、三苯基氧膦铽三元配合物的合成、结构表征及荧光性能的研究

以硝酸铽、苯乙酮酸（HL）, 2, 2＇-联吡啶（dipy）、 1, 10-菲啰啉（phen）和三苯基氧膦（TPPO）合成了TbL3dipy（H2O）2, TbL3phen（H2O）2和TbL2（TPPO）2NO3 3种新型固态配合物. 用元素分析、电导率、红外光谱和核磁共振谱对其进行了表征, 确定了配合物的组成. IR表明, 配合物中羧酸根可能以单齿方式配位. 1HNMR显示, 苯乙酮酸根配位后苯环上5个氢原子的化学位移移向高场. 室温下测定了配合物的荧光激发光谱, TbL3dipy（H2O）2, TbL3phen（H2O）2和TbL2（TPPO）2NO3最佳激发波长分别为361.0, 359.0和367.0 nm;分别以最佳激发波长测定了配合物的发射光谱, 配合物TbL3dipy（H2O）2, TbL3phen（H2O）2 和TbL2（TPPO）2NO3显示Tb3＋离子的特征发射光谱, TbL3dipy（H2O）2和TbL3phen（H2O）2均产生四条谱带, 分别归属于^5D4-^7Fj（j= 6, 5,4,3）能级跃迁（TbL3dipy（H2O）2： 489.0, 545.0, 584.0, 620.0 nm;TbL3phen（H2O）2： 490.0, 544.0, 583.0, 620.0 nm）;但在相同测定条件下, TbL2（TPPO）2NO3仅显示5D4-7F5（544.0 nm）能级跃迁光谱. 3种配合物中TbL3dipy（H2O）2发光强度最高.     

Isolation and purification of honokiol and magnolol from cortex Magnoliae officinalis by high-speed counter-current chromatography

High-speed counter-current chromatography was used to isolate and purify honokiol and magnolol from cortex Magnoliae Officinalis (Magnolia officinalis Rehd. et Wils.), a plant used in the traditional Chinese medicine. A crude sample, 150 mg, was successfully separated with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.4:1:0.4, v/v), and the fractions were analyzed by high-performance liquid chromatography. The separation produced 80 and 45 mg of honokiol and magnolol with purities of 99.2 and 98.2%, respectively, in 2.5 h.     

Synthesis and Magnetism of 2-Hydroxy-1,3-propylene-bis(oxamato)-bridged Co~ⅡCu~ⅡCo~Ⅱ Complexes

ＳｙｎｔｈｅｓｉｓａｎｄＭａｇｎｅｔｉｓｍｏｆ２┐Ｈｙｄｒｏｘｙ┐１，３┐ｐｒｏｐｙｌｅｎｅ┐ｂｉｓ（ｏｘａｍａｔｏ）┐ｂｒｉｄｇｅｄＣｏⅡＣｕⅡＣｏⅡＣｏｍｐｌｅｘｅｓＭＩＡＯＭｉｎｇ－ｍｉｎｇ，ＣＨＥＮＧＰｅｎｇ，ＬＩＡＯＤａｉ－ｚｈｅｎｇＪＩＡ...     

偶合反应化学发光法测定痕量银的研究

本将Ａｇ（Ⅰ）催化Ｓ２Ｏ＾２－８氧化Ｍｎ（Ⅱ）生成ＭｎＯ＾－４的催化反应与ＬｕｍｉｎｏｌＭｎＯ＾－４－ＯＨ＾－的化学发光反应相偶合，建立起一种新的灵敏测定痕量银的化学发光分析法，在所研究的优化条件下，该法测定银的选择性较好，检测限达到３．２×１０＾－１２ｇ／ｍＬＡｇ线性浓度范围为１．０×１０＾－１１－１．０×１０＾－５ｇ／ｍＬＡｇ，用于水样分析，结果较为满意。     

Atomic radical—molecule reactions F + CH<Subscript>3</Subscript>C≡CH: mechanistic study

The reaction of atomic radical F with propyne has been studied theoretically using ab initio quantum chemistry methods and transition state theory. The potential energy surface was calculated at the CCSD(T)/aug-cc-pVDZ (single-point) level using the UMP2/6-311++G(d,p) optimized structures. Two reaction mechanisms including the addition–isomerization–elimination reaction mechanism and the directed hydrogen abstraction reaction mechanism are considered. For the hydrogen abstraction reactions, i.e., the most probable evolution pathway in the title reaction, the HF formation occurs via direct abstraction mechanism dominantly and the H atom picked up by the atomic radical F should come mostly from the methyl group of normal propyne. On the other hand, for the addition–isomerization–elimination mechanism, the most feasible pathway should be the atomic radical F attacking on the C≡C triple bond in propyne (CH₃C≡CH) to form a weakly-bound adduct A1 with no barrier, followed by F addition to the C≡C triple bond to form the low-lying intermediate isomer 5. Subsequently, isomer 5 directly dissociates to P3 H₂CCCHF + H via transition state TS₅/P3. The other reaction pathways on the doublet PES are less competitive due to thermodynamical or kinetic factors. Furthermore, based on the analysis of the kinetics of all channels through which the addition and abstraction reaction proceed, we expect that the competitive power of reaction channels may vary with experimental conditions for the title reaction. The present work will provide useful information for understanding the processes of atomic radical F reaction with other unsaturated hydrocarbons. This material is available from author via E-mail.     

Inhibition of CO oxidation on RuO2(110) by adsorbed H2O molecules

Catalytic CO oxidation on the RuO(2)(110) surface was studied at 300 K by scanning tunneling microscopy (STM), high-resolution electron-energy-loss spectroscopy (HREELS), and thermal desorption spectroscopy (TDS). Upon repeatedly exposing the surface to several 10 L of CO and O(2) at 300 K, STM shows that unreactive features accumulate with each CO and O(2) titration run. HREELS and TDS show formation of increasing amounts of H(2)O, retarded formation of O-cus atoms and incomplete removal of CO-bridge molecules during O(2) dosing, and a changing ratio of single- and double-bonded CO-bridge molecules. It is concluded that H(2)O (presumably from the residual gas) is accumulating at the Ru-cus sites thus blocking them, so that the dissociative adsorption of oxygen is prevented and the CO oxidation reaction is suppressed. Some 10% CO- bridge remains on the surface even during oxygen exposure. Consistent with this interpretation, deactivation of the surface is suppressed at 350 K, at the onset of H(2)O desorption.     

Single Atoms of Iron on MoS2 Nanosheets for N2 Electroreduction into Ammonia

Efforts have been devoted to achieving a highly efficient artificial synthesis of ammonia (NH₃). Reported herein is a novel Fe-MoS₂ catalyst with Fe atomically dispersed onto MoS₂ nanosheets, imitating natural nitrogenase, to boost N₂ electroreduction into NH₃ at room temperature. The Fe-MoS₂ nanosheets exhibited a faradic efficiency of 18.8 % with a yield rate of 8.63 μg mg_cat.⁻¹ h⁻¹ for NH₃ at −0.3 V versus the reversible hydrogen electrode. The mechanism study revealed that the electroreduction of N₂ was promoted and the competing hydrogen evolution reaction was suppressed by decorating the edge sites of S in MoS₂ with the atomically dispersed Fe, resulting in high catalytic performance for the electroreduction of N₂ into NH₃. This work provides new ideas for the design of catalysts for N₂ electroreduction and strengthens the understanding about N₂ activation over Mo-based catalysts.     

Enhanced thermal properties and flame retardancy from a thermosetting blend of a phosphorus‐containing bismaleimide and epoxy resins

Epoxy resins modified by an organosoluble phosphorus‐containing bismaleimide (3,3′‐bis(maleimidophenyl) ­phenylphosphine oxide; BMPPPO) were prepared by simultaneously curing epoxy/diaminodiphenylmethane (DDM), and BMPPPO. The resulted epoxy resins were found to exhibit glass transition temperatures as high as 212 °C, thermal stability at temperatures over 350 °C, and excellent flame retardancy with Limited oxygen index (LOI) values around 40. Incorporation of BMPPPO into epoxy resins via the thermosetting blend was demonstrated to be an effective way to enhance the thermal properties and flame retardancy simultaneously. Copyright © 2003 John Wiley & Sons, Ltd.     

An Integrated Theory of Adsorption and Partition Mechanism and Eash Contribution to Solute Retention in Reversed Phase Liquid Chromatography

With the combination of the the stoichiometric displacement model for retention (SDM-R) in reversed phase liquid chromatography (RPLC) and the stoichiometric displacement model for adsorption (SDM-A) in physical chemistry,the total number of moles of the re-solvated methanol of stationary phase side.nr,and that of solute side in the mobile phase,q,corresponding the one mole of the desorbing solute,were separately determined and referred as the characterization parameters of the contributions of the adsorption mechanism and partition mechanism to the solute retention,respectively.A chromatographic system of insulin,using mobile phase consisting of the pseudo-homologue of alcohols(methanol,ethanol and 2-propanol)-water and trifluoroacetic acid was employed.The maximum number of the methanol layers on the stationary phase surface was found to be 10.6,only 3 of which being valid in usual RPLC,traditionally referred as a volume process in partition mechanism.However,it still follows the SDM-R.Both of q and nr of insulin were found not to be zero,indicating that the retention mechanism of insulin is a mixed mode of partition mechanism and adsorption mechanism.When methanol is used as the organic modifier,the ratio of q/nr was 1.13,indicating the contribution to insulin retention due to partition mechanism being a bit greater than that due to adsorption mechanism.A linear relationship between q,or nr and the carbon number of the pseudo-homologue in the mobile phase was also found.As a methodology for investigating the retention mechanism retention and behavior of biopolymers.a homologue of organic solvents as the organic modifier in mobile phase has also been explored.     

路易氏剂分析研究进展

简述了路易氏剂的危害，对路易氏剂的化学分析法和仪器分析法研究进展作一综述。