玫瑰花状多孔碱式碳酸镁微球的合成

介绍了一种便利的玫瑰花状多孔碱式碳酸镁(4MgCO₃·Mg(OH)₂·4H₂O)微球的合成方法,该方法分为三水碳酸镁(MgCO₃·3H₂O)前驱物合成与其在水中的热解制备过程。采用搅拌诱导结晶辅助陈化的方法合成前驱物,得到长约115 μm,长径比约10.4的均一微棒,将微棒在353.2 K的水中热解,即可得到由弯曲的纳米片组成的具有“卡片箱”结构（house of cards）的玫瑰花状多孔碱式碳酸镁微球,微球直径为30~60 μm,平均约40 μm,具有良好分散性。研究了热解过程中的形貌转变和相转移过程,采用XRD,FTIR及SEM表征样品的结构和形貌。结果表明：MgCO₃·3H₂O在较高温度下因不稳定而溶解,形成局部过饱和,生成无定形颗粒,并在微棒上成核结晶为4MgCO₃·Mg(OH)₂·4H₂O纳米片。纳米片由与微棒附着部位向外生长,形成玫瑰花状微球,微球长大伴随微棒的消溶,生长在棒上不同部位的颗粒在微观结构上将留有不同痕迹。分析认为热解转变过程是(MgCO₃·3H₂O)溶解－无定形物生成-(4MgCO₃·Mg(OH)₂·4H₂O)结晶的过程。     

溶剂热/水热条件下空旷结构草酸锌的合成

应用水热法及溶剂热方法，选择两种模板剂1，2-丙二胺和4，5-二氮芴-9-酮连氮(L)设计合成了草酸锌空旷结构材料[Zn₂(C₂O₄)3][C₃H₁₂N₂]·H₂O (Ⅰ)和[Zn₂(C₂O₄)₃]·L·6[H₃O] (Ⅱ)，使用CHN元素分析、     

纳米Zn-Co铁氧体的固相合成及电磁损耗特性研究

采用NH₄HCO₃与FeCl₃·6H₂O，Zn(NO₃)₂·6H₂O，Co(NO₃)₂·6H₂O进行室温固相反应制得前驱物，经微波加热处理后，进而热分解分别制得复合氧化物ZnFe₂O₄、CoFe₂O₄和Co_0.5Zn_0.5Fe₂O₄。由激光粒度分析仪、XRD和SEM表征：获得了颗粒分布比较均一、平均粒度为65 nm左右、立方晶系尖晶石结构的纳米铁氧体粉体。经测试样品的相对介电常数和相对磁导率后，研究了它们的电磁损耗特性。结果表明：Co_0.5Zn_0.5Fe₂O₄在100～1 800 MHz内比另外两种铁氧体具有更好的电磁损耗特性。     

2，3-吡嗪二甲酸钴(Ⅱ)配合物的合成与结构

在不同的反应介质条件中，用2，3-吡嗪二甲酸(C₄N₂H₂(COOH)₂，简称Pzdc)与Co(NO₃)₂·6H₂O或Co(ClO₄)₂·6H₂O反应，得到了三个新的不同组成的2，3-吡嗪二甲酸钴(Ⅱ)配合物，并进行了表征。通过X射线晶体结构分析，获得了Co(Pz(COO)COOH)₂·2H₂O的晶体学数据，表明Co(Ⅱ)处于由Pzdc中的2个N、2个O及2个配位水中的2个O组成的八面体结构中。同时，我们对CoPz(COO)₂·4H₂O和CoPz(COO)COOH(ClO₄)·4H₂O进行了变温磁化率测试，结果表明这两个化合物都存在弱的反铁磁相互作用。     

三元体系YCl3-CdCl2-H2O和四元体系YCl3-CdCl2-HCl(～8.8%)-H2O (25 ℃)的相平衡及其固相新化合物的研究

The equilibrium solubilities of the ternary system YCl₃-CdCl₂-H₂O, the quaternary system YCl₃-CdCl₂-HCl(～8.8%)-H₂O were determined at 25 ℃ and the phase diagrams were constructed. The results show that the ternary system was complicated with six equilibrim solid phases CdCl₂·2.5H₂O, CdCl₂·H₂O, 8CdCl₂·YCl₃·15H₂O (8∶1 type), 4CdCl₂·YCl₃·13H₂O(4∶1 type), 5CdCl₂·2YCl₃·26H₂O (5∶2 type) and YCl₃·6H₂O. The quaternary system was also complicated with four equilibrim solid phase CdCl₂·H₂O, 4CdCl₂·YCl₃·13H₂O (4∶1 type), 5CdCl₂·2YCl₃·26H₂O(5∶2 type) and YCl₃·6H₂O. Among the three new compounds 8CdCl₂·YCl₃·15H₂O, 4CdCl₂·YCl₃·13H₂O and 5CdCl₂·2YCl₃·26H₂O, 8CdCl₂·YCl₃·15H₂O was a kind of metastable compound only in ternary system, and it was changed into 4CdCl₂·YCl₃·13H₂O with time. Both 4∶1 type and 5∶2 type existed in ternary and quaternary system, but they were also congruently soluble compounds in quaternary system. They have been prepared from the system and have been characterized by XRD, TC-DTG and DSC.     

四元体系CdCl2-LaCl3-(9.7%)HCl-H2O在298K的相平衡及其固相化合物的研究

The equilibrium solubility of the LaCl₃-CdCl₂-(9.7%)HCl-H₂O quaternary system at 298K was determined and the phase diagram was constructed. The results show that the system is complicated with four equilibrium solid- phases CdCl₂·H₂O， 8CdCl₂·LaCl₃·16H₂O(8∶1 type)， 4CdCl₂·LaCl₃·12H₂O(4∶1 type) and LaCl₃·7H₂O， respectively. The two new compounds 8CdCl₂·LaCl₃·16H₂O(8∶1 type) and 4CdCl₂·LaCl₃·12H₂O(4∶1 type) are congruently soluble in ～9.7% HCl-H₂O medium and have not yet been reported in literatures. Both com-pounds have been prepared from the system and have been characterized by XRD， TG-DTG and DSC.     

新法合成手性磷酸锌钠

对合成手性磷酸锌钠(NaZnPO₄·H₂O) (CZP)的新方法进行了研究,用Na₃PO₄·12H₂Oand ZnSO₄·7H₂O作为起始原料,聚乙二醇-400（PEG-400）为表面活性剂,通过一步低热固相反应得到了手性磷酸锌钠。用TG/DTG,XRD, TEM 及 SEM表征了产物。实验结果表明,Na₃PO₄·12H₂O与ZnSO₄·7H₂O的配比采用不同的p/Zn比（0.9～1.15）,在60 ℃下陈化不同的时间(2.0～8.0 h) 所得到的NaZnPO₄·H₂O,除了结晶度稍为不同之外,晶体的手性结构是一样的。对照实验的结果显示陈化温度及阴离子调控着NaZnPO₄·H₂O的对映体形态。即,若以ZnSO₄·7H₂O或Zn(NO₃)₂·6H₂O为锌源,当反应混合物在60 ^oC陈化时,生成产物的结构是空间群为 P6₁22 的第一种手性结构,当反应混合物在室温陈化时,生成产物的结构则是空间群为 P6₅22 的第二种手性结构。     

咪唑配位的夹心型锑钨多氧酸盐Na9[{Na(H2O)2}3{M(C3H4N2)}3(SbW9O33)2]·xH2O (M= NiII, CoII, ZnII, MnII)

在pH≈7.5的水溶液中，Na₂WO₄·2H₂O,SbCl₃·6H₂O, 咪唑与 NiCl₂·6H₂O (或MnSO₄·H₂O,Co(NO₃)₂·6H₂O, ZnSO₄·7H2O)反应得到了四种咪唑配位的夹心型锑钨多氧酸盐Na₉[{Na(H₂O)₂}₃{M(C₃H₄N₂)}₃(SbW₉O₃₃)₂]·xH₂O(M=NiII, x = 32, CoII, x = 32,ZnII, x = 33, MnII, x = 34)。用X射线单晶衍射法确定了Na₉[{Na(H₂O)₂}₃{Ni(C₃H₄N₂)}₃(SbW₉O₃₃)₂]·32H₂O的结构,聚阴离子{Na(H₂O)₂}₃{Ni(C₃H₄N₂)}₃(SbW₉O₃₃)₂]₉-具有近似C_3v对称性，3个咪唑环垂直于中心带上六个金属离子(Na-Ni-Na-Ni-Na-Ni)所形成的平面。晶体结构中相邻的阴离子间存在着π-π相互作用，相邻咪唑的二面角为60º。用IR, UV-vis, TG 和DSC,对这些化合物的性质进行了表征，推测了它们的热分解过程。     

吡啶-2,5-二羧酸钐(Ⅲ)、镝(Ⅲ)配合物的合成、结构及性质

以Sm(NO₃)₃·6H₂O、Dy(NO₃)₃·6H₂O、吡啶-2,5-二羧酸(H₂pydc)为原料, 用水热合成法合成了2个新的稀土金属配合物[Ln(pydc)₂(H₂O)₅]·4H₂O(Ln=Sm (1), Dy (2)), 单晶结构经X单晶衍射仪分析确定, 两种配合物的晶系均为单斜晶系, C2/c空间群。对晶体的性质进行元素分析、热重、红外光谱, 荧光等分析。结果表明, 配合物1和2在常温下表现出稀土离子相应的特征荧光发射。另外, 本文对两种配合物进行了热稳定性及动力学分析。     

从P-Mo(Ⅴ)杂多化合物合成多形貌Al13基钼酸盐晶体

以H₃PMo₁₂O₄0·nH₂O、H₄PMo₁₁VO₄₀·nH₂O和(NH₄)₆P₂Mo₁₈O₆₂·nH₂O 3种杂多化合物为钼源，采用直接混合后陈化的方法合成了多形貌Al₁₃基钼酸盐晶体，相应Al₁₃基钼酸盐晶体的形貌和尺寸分别是斜方三棱柱形(80 μm × 30 μm)、星形(30 μm × 10 μm)和叶片形(500 μm × 150 μm)。粉末X射线衍射结果表明这3种多形貌Al₁₃基钼酸盐晶体结晶较好，在2θ为6.65°、8.00°和14.16°处都有强而尖锐的衍射峰。而以Na₂MoO₄·2H₂O为钼源时只能制得无定形簇合物。根据ICP、FTIR和TG/DTG结果给出多形貌的Al₁₃基钼酸盐晶体的化学简式为Na[AlO₄Al₁₂(OH)₂₄(H₂O)₁₂][MoO₄]₄·8H₂O。初步探讨了Al₁₃基钼酸盐晶体的形成机理。     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.