铑(Ⅲ)-溴酸钾-三氯偶氮氯膦催化分光光度法测定微量铑

铑（Ⅲ）在酸性介质中对溴酸钾氧化三氯偶氮氯膦的褪色反应有明显的催化作用。确定了最佳反应条件，建立了测定微量铑的催化分光光度新方法。铑在1．0～50．0μg／L范围内符合比耳定律，其表观摩尔吸光系数ε550＝1．08×106L·mol-1·cm-1。用于铂－铑催化剂中铑的测定，结果满意。     

La(Ⅲ)-(CPA-DBC)-乳化剂OP显色体系光度法测定分子筛中镧

在1．4 mol·L-1盐酸介质中,且有非离子型表面活性剂OP的存在下,二溴氯偶氯氯膦(CPA-DBC)与镧(Ⅲ)反应生成稳定的螯合物,其吸收峰位于642 nm波长处,摩尔吸光系数(ε642)为1．06×105L·mol-1·cm-1,与相同显色反应但不加OP时相比较,其灵敏度提高了49．3％,镧(Ⅲ)浓度在0～12μg／25 mL范围内遵守比耳定律。将此方法应用于测定分子筛试样中镧含量时,测得结果的平均RSD(n=5)为2．5％,平均回收率为97．7％。     

褪色光度法测定氯酸根离子

研究了在盐酸介质中，氨酸根氧化甲基橙使其褪色的最佳条件，提出了一种测定微量氨酸根离子的新方法。最大吸收波长λmax=510nm，表观摩尔吸光系数ε=1．0×105L.mol-1·cm-1，氨酸根离子浓度在0．2－0．6mg／Ｌ范围内符合比耳定律。本法快速、简便、选择性好，可用于化学试剂中氯酸根离子的测定，结果满意。     

盐酸氯丙嗪-卤代荧光素体系的光度法测定

在NaAc HCl缓冲介质中,盐酸氯丙嗪可与曙红Y、赤藓红、乙基署红等卤代荧光素染料反应,形成离子缔合物,溶液颜色发生明显改变,可用光度法测定。盐酸氯丙嗪的浓度在0～1.6×10-5mol·L-1(曙红Y)、0～1.3×10-5mol·L-1(赤鲜红)、0～1.5×10-5mol·L-1(乙基曙红)范围内遵守比耳定律,其表观摩尔吸光系数分别为4.63×104L·mol-1·cm-1、2.50×104L·mol-1·cm-1、为4.32×104L·mol-1·cm-1。方法用于片剂和针剂中盐酸氯丙嗪的测定,结果满意。     

偶氮氯膦-DBF吸光光度法测定药物中铋

在 0 .36mol·L- 1H2 SO4 0 .6 0mol·L- 1H3PO4 混合酸介质中 ,DBF 偶氮氯膦与铋形成蓝色配合物 ,最大吸收波长位于 6 38nm ,表观摩尔吸光系数为 9.4× 10 4 L·mol- 1·cm- 1,铋浓度在 0 30 μg/2 5ml范围内符合比耳定律。用直接光度法测定了果胶铋胶囊、陈香路白路片、枸橼酸铋钾颗粒等药物中铋 ,结果满意。     

人工神经网络分光光度法测定无机铬的形态

在二溴苯基荧光铜-溴化十六烷基三甲基-乙醇显色体系中,应用三层人工神经网络解析Cr(Ⅲ)和Cr(Ⅵ)的吸收光谱,分光光度法同时测定Cr(Ⅲ)和Cr(Ⅵ)。Cr(Ⅵ)和Cr(Ⅲ)的质量浓度分别在0～0．287 mg·L-1和0～0．131 mg·L-1范围内服从比耳定律,其表观摩尔吸光系数分别为ε580=1．13×105L·mol-1·cm-1和ε576=8．96×104L·mol-1·cm-1。使用改进的BP网络,避免了网络学习过程中可能产生的陷入局部极小点,并提高了其收敛速度和泛化能力。经合成样品和实际样品分析,考核了方法的回收率和精密度。     

双波长吸光光度法同时测定多巴和酪氨酸的研究

研究了双波长吸光光度法同时测定多巴和酪氨酸。在 pH 1 2 .0 0的硼砂 氢氧化钠缓冲介质中 ,多巴和酪氨酸的含量分别在 0～ 2 0 .0 μg·ml-1和 0～ 1 9.0 μg·ml-1范围内呈良好线性关系 ,方法检出限和摩尔吸光系数 :多巴为 0 .2 3 μg·ml-1和 1 .2 0× 1 0 4L·mol-1·cm-1,酪氨酸为 0 .2 7μg·ml-1和 1 .48× 1 0 4L·mol-1·cm-1,方法的灵敏度和和选择性均较好 ,应用于尿液中多巴和酪氨酸的测定。     

2-(6-甲基苯并噻唑)偶氮间苯二酚与铂显色反应研究

本文研究了显色剂 2 - ( 6-甲基苯并噻唑偶氮 )间苯二酚 ( MBTAP)与铂 ( )的显色反应。在表面活性剂溴代十四烷吡啶存在下 ,于 p H5 .0的醋酸溶液中 ,形成紫红色配合物 ,其最大吸收波长在 61 9nm,表观摩尔吸光系数为 ε=1 .1 3× 1 0 5L·mol- 1· cm- 1。铂元素含量在 0～ 1 0 .0 μg/2 5 m L范围内服从比尔定律。方法用于 Pt-C催化剂样品的分析 ,结果令人满意     

克霉唑与氯冉酸的荷移反应及其测定

克霉唑与氯冉酸在丙酮介质中发生电荷转移反应 ,生成 1∶1型络合物 ,该络合物的λmax=5 2 5nm ,表观摩尔吸光系数是 1.2 2× 10 3 L·mol-1·cm-1,药物浓度在 0～ 30 0mg/L范围内符合比耳定律 ,6次测定的相对标准偏差为 1.4 % ,回收率在 97%以上。用拟定的方法测定药物片剂中有效成分的含量 ,结果与药典方法相符     

偶氮氯膦—DBC光度法测定银合金中镨

研究提出镨 ( ) - DBC-偶氮氯膦 -磷酸 - EDTA新体系光度法测定贵金属合金中微量镨。反应体系生成 α型蓝色配合物的 λmax=650 nm,灵敏度高 ,摩尔吸光系数 ε=0 .93× 1 0 5L·mol-1·cm-1,镨浓度在 0～ 50 μg/2 5ml范围内符合比耳定律 ,方法选择性强 ,有较好的适用性 ,用于分析银合金中镨 ,标准偏差 S≤ 0 .0 1 1 ,相对标准偏差 RSD≤ 1 .97%。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.