液相色谱-串联质谱法测定水产品中麻醉剂MS-222残留

建立了液相色谱-串联质谱法测定水产品中麻醉剂3-氨基苯甲酸乙酯甲基磺酸盐(MS-222)残留量的方法。提取液为50%的甲醇及乙酸-乙酸钠缓冲溶液,提取液经C18固相萃取柱净化处理后用液相色谱-串联质谱仪进行测定,外标法定量。流动相为0.5%的甲酸溶液和乙腈(V:V=60:40),流速为0.2 mL/min。该方法的线性范围为0.001～1.0 mg/L,相关系数大于0.999,检出限为1μg/kg,定量限为2μg/kg。加标回收率可以达到80%～110%。     

载体对含硫四氮杂卟啉铁(Ⅱ)/树脂催化剂降解水中有机污染物效率的影响

 考察了用阴离子交换树脂作为载体时对含硫四氮杂卟啉铁(Ⅱ)(简写为FePz(dtn)4)催化剂活化分子氧降解罗丹明B等水中有机污染物效率的影响. 结果表明,负载FePz(dtn)4催化剂的离子交换树脂对底物的吸附可在30 min内达到平衡. 在不同pH的溶液中,载体对不同底物分子的吸附量不同. 同一种底物在碱性溶液中的吸附量最大,催化降解速率最快. 负载于树脂上的FePz(dtn)4催化剂可重复使用. 初步探讨了催化剂对有机污染物降解的作用机理.     

用CR传输线模型研究涂层/金属体系阻抗谱

根据CR传输线模型和QR电路之间的关系,建立了拟合其初值的计算方法,借助Z-View软件,可求得各元件精确值.根据电容（Ci）和电阻（Ri）随特征频率（f*）的分布,推导了元件相对增量与恒相位角元件（Q）指数参数n的关系. 结果表明, 当n小于0.5时,Ci比Ri增加得更快,从新的角度说明了n的物理意义及其和界面脱层之间的关系.作为应用实例,拟合了不同特征的电化学阻抗谱,分析了有机涂层/金属腐蚀体系阻抗变化的具体过程,区分了点蚀和脱层因素对阻抗谱的影响,从高阻抗体系同时得到了与不同空隙率有关的涂层电容和电阻值,并根据涂层体系的不均匀特征探讨了模型结构的物理意义.     

分散聚合水基聚苯胺乳胶微球制备与表征

水溶性空间稳定剂聚乙烯吡咯烷酮（PVP）存在时，采用分散聚合制备水溶性单分散的聚苯胺(PAn)乳胶粒子，采用透射电子显微镜（TEM）观察粒子形态及尺寸；利用紫外-可见吸收光谱对胶体分散体系进行表征.实验结果表明，当PAn含量较少（w< 16.78％）时， PAn-PVP复合乳胶粒子呈米粒状；当PAn含量较大（w >23.22％）时， PAn-PVP复合乳胶粒子呈球形.     

2,2’-二氨基苯氧基二硫化物的电极过程动力学研究

利用循环伏安法、线性伏安法及旋转圆盘电极技术，研究了2,2’-二氨基苯氧基二硫化物(DAPOD)在含有0.1 mol•L－1 LiClO4电解质的乙腈/四氢呋喃有机溶液中，铂、金、玻碳及石墨电极上的电化学行为.伏安结果表明DAPOD中的二硫键与硫巯基之间的氧化还原反应属动力学不可逆过程，这种在室温下表现出的电化学反应不可逆性是有机二硫化物普遍存在的不足，必须通过分子内或分子间的电催化来改善其可逆性能.旋转圆盘电极测试结果显示， DAPOD的阴极还原反应级数为0.5，阳极氧化反应级数为1.由此推知DAPOD电还原属两电子转移反应，分两步完成：第一步为平衡的化学反应步骤；第二步为电子转移步骤，属决速步.同时还测定了DAPOD的阴极与阳极传递系数、交换电流、平衡电势及标准速率常数等相关的动力学常数.通过比较铂、金、玻碳及石墨四种不同材料电极对DAPOD的电极过程的影响,发现石墨对DAPOD的还原过程具有电催化作用.     

N‐Heterocyclic Carbene–Palladium Complexes as Efficient Catalysts for the Oxidative Carbonylation of Amines to Ureas

A highly efficient oxidative carbonylation reaction of amines to ureas was developed making use of carbene–palladium complexes in the absence of any promoter. Both aliphatic amines and aromatic amines were transformed in good to excellent yields to the expected ureas.     

含铈类水滑石的制备及其衍生物催化研究

采用共沉淀水热法制备了镍铝铈三元复合层状氢氧化物.详细探讨了合成体系pH值、Ce/Al比及陈化条件对合成产物物相的影响;通过XRD,ICP,TG-DTA手段研究了合成物物相、组成及热行为.考察了以合成物为前驱体经焙烧后转化为镍铝铈复合金属氧化物在催化消除NO反应中的应用.实验结果表明,合成镍铝铈三元复合层状氢氧化物的适宜条件是:M2 /M3 =2,Ce/Al=0.07～0.75,pH=5.5～6.9,水热处理条件为110℃,5 h;在pH=5.5～6.9条件下,合成原料配比不同,产物物相相同,但组成不同;合成物热稳定性较差,在T=100～400℃之间,层间吸附水及层间平衡阴离子NO3-脱去,转化为复合氧化物,将此氧化物应用于NO消除反应中,表现出高的低温活性,400℃进行反应,NO转化率达95%,N2选择性几乎100%.     

Syntheses and crystal structures of four silver(I) complexes based on 2-(4-pyridyl)benzimidazole

Four new silver(I) complexes constructed with 2-(4-pyridyl)benzimidazole, namely, [Ag(PyBIm) · H₂O] · NO₃ (1), [Ag(PyBIm) · H₂O] · ClO₄ (2), [Ag₂(PyBIm)₂] · (SiF₆) · 2H₂O (3) and [Ag(PyBIm) · (HBDC)] (4) (PyBIm = 2-(4-pyridyl)benzimidazole, BDC = 1,3-benzenedicarboxylate) have been synthesized and characterized by X-ray crystallography. All the silver(I) atoms in complexes 1–4 are bridged by the different PyBIm ligands via N_Py and N_BIm into one-dimensional “zigzag” chains. The anions do not coordinate to the silver(I) atoms and only act as counter ions in complexes 1–3. Due to the anions, different hydrogen bonding systems are found in those three compounds, resulting in the different crystal packing. Through hydrogen bonding interactions, the structures of complexes 1–3 display a double layer, a three-dimensional framework and a novel double chain, respectively. In complex 4, the HBDC⁻ anions act not only as a counter ion but also as bridging ligands, which lead the “zigzag” [Ag₂(PyBIm)₂]_∞ chain into a two-dimensional undulating sheet. The sheets are connected through hydrogen-bonding as well as π–π interactions into a three-dimensional framework. The thermal stabilities of the four complexes and anion exchange properties of complexes 2 and 3 were also studied.     

Synthesis and Photophysical and Electrochemical Study of Tyrosine Covalently Linked to High‐Valent Copper(III) and Manganese(IV) Complexes

As bio‐inspired chemical model of the oxygen‐evolving complex (OEC) in photosystem II, a new tyrosine‐modified corrole ligand 3 and its high‐valent copper and manganese complexes 3a and 3b were synthesized and characterized. The copper complexes 1a and 2a of corrole 1 and 2 were also prepared for comparison. The emission property indicates that the emission of ligands 2 and 3 is located at 670 nm, but no emission is observed for their metal complexes due to its suppression by the metal center. The electrochemical study shows that 3a might dimerize at the first two reversible oxidations, a behavior which was not observed in the case of 1a and 2a . The corrolato manganese(IV) complex 3b shows one reversible reduction and one quasireversible oxidation at ?0.17 and 0.77 V vs. Ag/Ag⁺, respectively.