新型"分子合金"类Fe(II)配合物的合成和自旋转换性能

合成了Fe[(Htrz)~9~/~4(NH~2trz)~3~/~4](BF~4)~2.H~2O(1)和Fe[(Htrz)~3~/~2(NH~2trz)](BF~4).3H~2O(2)两个"分子合金"类自旋转换配合物。其变温光谱表明,它们在室温附近具有自旋转换行为,同时还伴有热致变色及滞后现象。     

自旋转换氧化石墨烯纳米复合材料的制备及磁性

利用氧化石墨烯(GO)表面具有丰富含氧基团的特点,采用原位生长法将经典的亚铁三氮唑自旋转换(SCO)配位聚合物[Fe(Htrz)2(trz)](BF4)负载到二维材料GO的表面。利用X射线粉末衍射(PXRD)、红外光谱(FTIR)、SEM、TEM、拉曼等手段对自旋转换-氧化石墨烯(SCO-GO)纳米复合材料进行了表征。通过光谱表征发现,复合材料的FTIR和PXRD特征峰为GO和[Fe(Htrz)2(trz)](BF4)特征峰的叠加,初步证明了自旋转换-氧化石墨烯纳米复合材料已成功制备。SEM和TEM分析直观地显示立方体状的[Fe(Htrz)2(trz)](BF4)纳米颗粒均匀地分散在氧化石墨烯表面,且随着原位生长时间的增加,GO表面的[Fe(Htrz)2(trz)](BF4)的负载量增加、尺寸增大。拉曼图谱表明[Fe(Htrz)2(trz)](BF4)负载到GO表面后,氧化石墨烯特征拉曼峰的强度比(ID/IG)增大,说明氧化石墨烯的缺陷密集程度增大,[Fe(Htrz)2(trz)](BF4)纳米颗粒与石墨烯之间的作用力增强。磁性测试表明不同自组装时间(1、6、12 h)的SCO-GO复合材料的T1/2↑分别为381.1、381.5和382.4 K,T1/2↓分别为345.9、345.0和344.8 K,其磁滞回线宽度分别为35.2、36.5和37.6 K,这是由于不同自组装时间的SCO-GO复合材料中[Fe(Htrz)2(trz)](BF4)的负载量和尺寸的差异导致的。DSC分析结果和磁性结果一致,证实了SCO-GO复合材料自旋转变温度向高温区移动。     

自旋转换-氧化石墨烯纳米复合材料的制备及磁性

利用氧化石墨烯（GO）表面具有丰富含氧基团的特点,采用原位生长法将经典的亚铁三氮唑自旋转换（SCO）配位聚合物[Fe（Htrz）₂（trz）]（BF₄）负载到二维材料GO的表面。利用X射线粉末衍射（PXRD）、红外光谱（FTIR）、SEM、TEM、拉曼等手段对自旋转换-氧化石墨烯（SCO-GO）纳米复合材料进行了表征。通过光谱表征发现,复合材料的FTIR和PXRD特征峰为GO和[Fe（Htrz）₂（trz）]（BF₄）特征峰的叠加,初步证明了自旋转换-氧化石墨烯纳米复合材料已成功制备。SEM和TEM分析直观地显示立方体状的[Fe（Htrz）₂（trz）]（BF₄）纳米颗粒均匀地分散在氧化石墨烯表面,且随着原位生长时间的增加,GO表面的[Fe（Htrz）₂（trz）]（BF₄）的负载量增加、尺寸增大。拉曼图谱表明[Fe（Htrz）₂（trz）]（BF₄）负载到GO表面后,氧化石墨烯特征拉曼峰的强度比（ID/IG）增大,说明氧化石墨烯的缺陷密集程度增大,[Fe（Htrz）₂（trz）]（BF₄）纳米颗粒与石墨烯之间的作用力增强。磁性测试表明不同自组装时间（1、6、12 h）的SCO-GO复合材料的T_1/2↑分别为381.1、381.5和382.4 K,T_1/2↓分别为345.9、345.0和344.8 K,其磁滞回线宽度分别为35.2、36.5和37.6 K,这是由于不同自组装时间的SCO-GO复合材料中[Fe（Htrz）2（trz）]（BF4）的负载量和尺寸的差异导致的。DSC分析结果和磁性结果一致,证实了SCO-GO复合材料自旋转变温度向高温区移动。     

层状液晶中水溶性超微粒子材料[Co(NH~3)~6]Cl~3的制备

利用溶剂在层状液晶中的渗透性和层状液晶中溶剂厚度的限定性, 在TritonX-100/C~10H~21OH/H~2O体系层状液晶中, 以4%Co(NH~3)~6]Cl~3水溶液组分水制备水溶性超微粒子材料[Co(NH~3)~6]Cl~3, 粒径约为3~6nm。     

Mo~2S~4[S~2CNC~4H~8]~2的合成、结构表征及其与Cu^+,Ni^2+的反应

由(NH~4)~2Mo~2S~12H~2O和(NH~4)(S~2CNC~4H~8)在PPh~3参与反应下,获得Mo~2S~4(S~2CNC~4H~8)~2化合物,对此二核钼簇合物进行了红外、电子光谱、电化学及单晶X射线结构表征,并尝试与多种金属化合物进行[2+1]反应,从反应产物的晶体结构分析发现了包括金属夺取端基S^2-形成Mo~2O~2S~2(S~2CNC~4H~8)~2化合物,Cu^+被氧化并夺取配体(S~2CNC~4H~8)^-形成Cu(S~2CNC~4H~8)~2以及Mo(V)还原为Mo(IV),S^2-氧化为(S~2)^2-而形成Mo~3(μ~3-S)(μ-S~2)~3[S~2CNC~4H~8]~3.     

一些含半夹心结构VIB族金属的1, 1'-二硫(硒)二茂铁化合物的 合成

Cp^*Cr(NO)(CO)~2与Fe(C~5H~4S)~2S反应,形成氧化-还原产物Cp^*Cr(NO)(SC~5H~4)~2Fe(1)。双杂核二茂铁化合物Cp^*M(NO)(EC~5H~4)~2Fe[M=Mo,E=S(2a),Se(2b);M=W,E=S(4a),Se(4b)]、CpMo(NO)(SC~5H~4)~2Fe(3)、Cp~2Mo(SeC~5H~4)~2Fe(6)和Cp~2W(SC~5H~4)~2Fe(7)可通过Fe(C~5H~4ELi)~2.2THF(E=S,Se)与Cp^*M(NO)I~2(M=Mo,W)、[CpMo(MO)I~2]~2或Cp~2MCl~2(M=Mo,W)反应制得。三核杂原子二茂铁化合物[Cp^*Cr(NO)~2]~2(EC~5H~4)~2Fe[E=S(8a),Se(8b)],由Fe(C~5H~4ELi)~2.2THF(E=S,Se)与二倍摩尔量的Cp^*Cr(NO)~2I反应制备。通过AgBF~4氧化2a得到二茂铁离子型化合物[Cp^*Mo(NO)(SC~5H~4)~2Fe]^+BF~4^-(5)。采用元素分析、红外光谱、^1H和^1^3CNMR谱以及EI-MS表征了所合成的新型化合物。     

氯氟烃的选择性还原及其在合成含氟麻醉剂中的应用

本文阐述了用过硫酸铵/醋酸氨[ (NH~4)~2S~2O~8/HCOONH~4 ]和过硫酸铵/磷酸二氢钠·水[ (NH~4)~2S~2O~8/NaH~2PO~2·H~2O ]选择性还原1,1,3,4-四氯全氟丁烷CF~2ClCFClCF~2CFCl~2。介绍了应用这类选择性还原反应合成含氟吸入性麻醉剂CHF~2OCF~2CHClF (Enflurane)和CHF~2OCHClCF~3 (Isoflurane)。     

一维链状氰根桥联配合物 [Sm(DMA)~2(H~2O)~4Fe(CN)~6·5H~2O]~n的合成和晶 体结构

以K~3Fe(CN)~6,N,N-二甲基乙酰胺和Sm(NO~3)~3·6H~2O合成了标题配合物[Sm(DMA)~2(H~2O)~4Fe(CN)~6·5H~2O]~n,并通过元素分析,红外光谱进行了表征。利用单晶X射线四圆衍射法测定了晶体结构,结果表明晶体属斜晶系,P2~1/c空间群,晶胞参数a=1.02744(4)nm,b=1.6732(2)nm,c=1.7323(2)nm,β=97.385(3)°,Z=4,R~1=0.0412。     

超微盘电极线性扫描伏安法准稳态准可逆波理论

本文提出超微盘电极上线性扫描准稳态准可逆伏安曲线表达式, 并用铂超微盘电极、(NH~4)~2Fe(SO~4)~2-1mol·dm^-^3H~2SO~4体系进行了验证, 理论与实验相符。     

trans-[(en)~2(NO~2)Co(O~2CC~5H~5N)]^2^+/Fe(Ⅱ)间电子转移反应动力学及机理研究

合成了新型Co(Ⅲ)配合物trans-[(en)~2(NO~2)Co(O~2CC~5H~5N)](ClO~4)~2, 并通过紫外可见光谱、红外光谱、元素分析和X射线单晶衍射分析进行了表征。同时分别以[Fe(CN)~6]^4^-和[Fe(CN)~5(H~2O)]^3^-作为还原剂, 考察了该配合物被还原的反应动力学行为。结果表明两反应体系分别按外配位界机理和内配位界机理进行电子传递。在25℃, Ⅰ=0.5mol·L^-^1,trans-[(en)~2(NO~2)Co(O~2CC~5H~5N)]^2^+/[Fe(CN)~6]^4^-反应体系的前驱配合物离子对形成常数Q~i~p=29mol^-^1·L, 电子转移速率常数k~e~t=2.4×10^-^4s^-^1,电子转移过程的活化焓△H^≠~e~t和活化熵△S^≠~e~t分别为1.2×10^2kJ·mol^-^1和5.0×10^2J·mol^-^1·K^-^1。在40℃, pH=8.0, Ⅰ=0.1mol·L^-^1,trans-[(en)~2(NO~2)Co(O~2CC~5H~4N)]^2^+/[Fe(CN)~5(H~2O)]^3^-反应体系前驱双核配合物分子内电子转移速率常数为7.0×10^-^5s^-^1。最后讨论了分子轨道对称性, 两金属中心氧化还原电势差等因素对电子转移速率的影响。     

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.     

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.     

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.     

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.