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1.
稀土钼磷杂多蓝的合成、性质及防治植物病毒的研究   总被引:3,自引:0,他引:3  
采用电解法合成了Keggin结构稀土钼磷二,四电子杂多蓝,通式为LnH2「PMo^V110Mo2^vO40」,nH2O和LnH4「PMo^VI8Mo^v4O40」.nH2O(Ln=La,Ce,Pr,Nd,Sm,Gd)。  相似文献   

2.
本文首次合成出八种Keggin结构的稀土元素钨锗杂多配合物LnHGeW12O40·xH2O(简写为LnHGeW12,Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Yb;x=18~28)。用ICP,183WNMR,X射线粉末衍射,IK,UV,循环伏安和TG-DTA热分析等手段,对这些杂多配合物进行了表征和性质研究,讨论了结构和性质的关系,为此类配合物的催化应用提供了有益信息。  相似文献   

3.
Keggin结构合钒混配型杂多蓝的离析和性质研究   总被引:1,自引:0,他引:1  
本文利用控制电位电解法首次制备出三元、四元含钒混配型-电子杂多蓝K4H2《SiV^ⅣMo2W9O40].12H2O和两电子杂多蓝K4H5[Si^ⅣV^ⅤW9O40].11H2O通过元素分析,IR、UV-可见电子光谱,ESR、XPS和X射线粉末衍射对产物进行了表征和性质研究,结果表明:杂多酸盐还原为杂多蓝后仍保持Keggin结构,但结构发生畸变,畸变程度随钒原子数值多而增大,还原电子具有一定的离域性  相似文献   

4.
本文利用控制电位电解法首次制备出三元、四元含钒混配型—电子杂多蓝K4H2[SiVⅣMo2W9O40]·12H2O和两电子杂多蓝通过元素分析、IR、UV—可见电子光谱、ESR、XPS和X射线粉末衍射对产物进行了表征和性质研究.结果表明:杂多酸盐还原为杂多蓝盾仍保持Keggin结构,但结构发生畸变,畸变程度随机原子数增多而增大.还原电子具有一定的离域性,并且离域程度与中心杂原子的种类有关.  相似文献   

5.
稀土锗钨钒酸根多元杂多配合物的合成和性质   总被引:8,自引:1,他引:8  
合成了通式为K13H2「Ln(GeW10VO39)2」.nH2O(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Yb)的10种杂多配合物。利用IR,UV,ESR,XPS,X射线粉末衍射和磁化率对其结构进行了表征:循环伏安和极谱法研究了配合物的氧化还原性质,得出配合物经历了3步还原,第一步为钒的双电子可逆还原,第二步和第三步均为钨的不可逆还原;借助认温IR、变温XRD和TG-DTA研究  相似文献   

6.
取代型钨镓杂多配合物的导电性及其磁性   总被引:11,自引:1,他引:11  
合成了过渡金属取代的钨镓杂多配合物α-Na7「GaW11Co(H2O)O39」.16H2O,α-Na7H2「GaW10Co2(H2O)2O39」.16H2O和α-NanHm「GaW9ME(H2O)3O37」.16H2O「M=Co(Ⅱ),Ni(Ⅱ,)V(Ⅴ)」,通过红外,紫外,ICP,TG-DTA,EPR,XPS,^183WNMR,极谱等手段进行了表征。  相似文献   

7.
甘氨酸的杂多酚超分子化合物的合成及性质研究   总被引:14,自引:1,他引:13  
首次合成了甘氨酸的Keggin结构杂多酸超分子化合物(HGly)3「PW12O40」.5H2O(HGly)4「SiW12O40」.4H2O,用元素分析,IR,UV,TG-DTA,XRD和NMR等方法对标题化合物进行了表征,并讨论了它们的合成条件及结构特性。  相似文献   

8.
稀土元素1:12系列钨锗杂多配合物的合成及性质研究   总被引:2,自引:0,他引:2  
本文首次合成出八种Keggin结构的稀土元素钨锗杂多配合物LnHGeW12O40.xH2O。用ICP,^183WNMR,X射线粉末衍射,IR,UV,循环伏安和TG-DTA热分析等手段,这些杂多配合物进行了表征和性质研究。讨论了结构和性质的关系,为此类配合物的催化应用提供了有效信息。  相似文献   

9.
本文用极谱,循环伏安和紫外吸收光谱方法研究了21种含钨1:12系列稀土元素杂多配合物LnPW12O40、LnHSiW12O40和LnHGeW12O40(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd)的氧化还原性质和溶液稳定性,讨论了抗衡离子、介质和酸度等因素对杂多阴离子氧化还原性的影响,对三种不同中心原子的杂多阴离子氧化还原顺序进行了比较,探讨了极谱半波电位与pH的关系,提出了氧化还原机理。  相似文献   

10.
合成了通式为K15H3〔Ce(P2W16VO61)2〕.61H2O、K15H4〔Ln(P2W16VO61)2〕.xH2O(Ln=La^3+,Pr^3+,Nd^3+,Sm^3+,Eu^3+,Gd^3+,Dy^3+,Yb^3+)的9种镧系元素Dawson结构的钨钒磷四元杂多配合物,并用IR、UV、NMR、ESR、XRD、TG-DTA等对其结构和性质进行子研究。该类配合物具有与K16〔Ce(P2W17O  相似文献   

11.
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%.  相似文献   

12.
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.  相似文献   

13.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

14.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

15.
16.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

17.
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.  相似文献   

18.
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.  相似文献   

19.
A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).  相似文献   

20.
Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO4 oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.  相似文献   

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