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1.
本文利用π-π堆积的方式在氧化石墨烯(GO)表面生长了Eu髥配合物纳米晶。傅立叶变换红外光谱(FTIR),透射电子显微镜(TEM),X-射线衍射(XRD)的表征证明,Eu髥配合物纳米晶成功地生长在氧化石墨烯表面。荧光光谱分析证明,复合材料具有一定的荧光性能,其中Eu3+的猝灭浓度为18wt%。热重分析显示,复合材料的热稳定性也比纯配合物有了明显的提高。  相似文献   

2.
[Eu2(BA)6(bipy)2]的晶体结构和荧光光谱   总被引:6,自引:0,他引:6       下载免费PDF全文
标题配合物晶体属单斜晶系,P21/n空间群,晶胞参数a=1.4162(3) nm,b=1.5377(5) (nm), c=2.6017(5) nm, β=103.56(3°), Z=4。标题配合物是双核分子,4个苯甲酸的羧基桥联两个中心Eu(Ⅲ)离子。它们又分别与1个苯甲酸的羧基的两个氧原子和一个联吡啶分子的两个氮原子螯合配位,形成4,4′-双帽三角棱柱体。两个Eu(Ⅲ)离子的Eu-O和Eu-N平均键长不等。两个Eu(Ⅲ)离子的化学环境略有不同。在配合物的 7F05D0激发光谱里,580.17和580.31 nm处呈现两个锐峰,可以认为配合物具有两种Eu(Ⅲ)格位,选择激发配合物的 5D0能级,得到的 5D07F1,2发光光谱表明配合物中Eu(Ⅲ)离子有不同的化学环境,这与晶体结构分析结果一致。  相似文献   

3.
以3-羧基苯磺酸根(3-SBA)和2-(4-吡啶基)-咪唑[4, 5-f]菲咯啉(4-PDIP)为配体, 用水热法合成了3种稀土配合物:[Ln2(3-SBA)2(4-PDIP)2(OH)2(H2O)4]·2H2O(Ln=Sm (1), Eu (2)和Gd (3))。用X-射线单晶衍射分析方法测定了其晶体结构。配合物1~3为同构的双核分子。2个羟基以桥联方式连接2个Ln(Ⅲ)离子, 3-SBA和4-PDIP以螯合双齿形式与Ln(Ⅲ)离子配位。双核分子之间通过氢键构筑成三维超分子结构。配合物13分别在 545 nm 和 529 nm 处出现来自于配体的荧光发射, 对应于配体的π*-π的跃迁。配合物2呈现Eu(Ⅲ)离子的特征发射, 位于579、592、612、650和696 nm处的发射峰分别对应于5D07Fj (j=0~4)跃迁。  相似文献   

4.
线性共轭高分子P-1是由单体1,4-二溴-2,3-二正丁氧基萘(M-2)和5,5′-二乙烯-2,2′-联吡啶(M-3)通过Pd催化Heck偶合反应合成得到,高分子配合物P-2P-3由高分子P-1和Eu(TTA)3·2H2O和Gd(TTA)3·2H2O反应生成。高分子P-1能发射强蓝绿色荧光。高分子配合物P-2P-3发光性能测试表明,含有Eu(Ⅲ)的高分子配合物P-2不仅显示高分子荧光,而且还显示了Eu(Ⅲ)(5D07F2)特征荧光,含Gd(Ⅲ)的高分子配合物P-3仅发射高分子的荧光,其荧光波长相对P-1而言,呈现13 nm红移。  相似文献   

5.
设计合成了一种D-π-A型(Donor-π-Accept)氰基羧酸二茂铁配体,它与有机锡化合物二丁基氧化锡(n-Bu2SnO)反应,得到了一种新型二茂铁有机锡羧酸酯配合物。通过1H NMR、119SnNMR、IR、FT-IR、UV-Vis和元素分析等对配体及其配合物进行了全面的表征,利用X-射线单晶衍射测定了配合物的晶体结构,运用CV和Z-scan测试方法系统地研究了它们的电化学和双光子吸收性质。结果表明:与配体相比较,配合物更难被氧化,且具有更大的双光子吸收截面。  相似文献   

6.
芳基与烷基亚砜钯(II)配合物π反馈效应的DFT研究   总被引:1,自引:0,他引:1  
应用DFT方法对二苯基亚砜(DPSO)和二己基亚砜(DHSO)的钯(II)配合物进行了理论计算。结果表明中心金属钯与亚砜之间存在d*反馈键,而且二苯基亚砜钯(II)配合物中的π反馈键比二己基亚砜钯(II)配合物强,即亚砜的取代基对其钯(II)配合物的π反馈键有显著的影响。以BHandH/6-31+G**(Pd,3-21G*)//BHandH/6-31G*(Pd,3-21G*)方法对相应的亚砜钯(II)配合物进行单点计算时,配合物trans-PdCl2(DPSO)2 的π反馈键轨道能为-10.695 eV,而trans-PdCl2(DHSO)2的π反馈键轨道能量为-10.320 eV。利用电子给体NH3或电子受体CO配位体置换亚砜钯(II)配合物里的一个亚砜配体后,Pd(II)-DHSO配合物的Pd-S配位键长的变化明显小于Pd(II)-DPSO配合物的Pd-S配位键长变化值,进一步说明在Pd-DPSO配合物中的π反馈效应强于相应的Pd-DHSO配合物。  相似文献   

7.
稀土金属离子与人血清白蛋白的相互作用   总被引:3,自引:0,他引:3  
本文用荧光光谱、紫外-可见吸收光谱法和循环伏安法研究了稀土金属离子Eu(Ⅲ)、Pr(Ⅲ)与人血清白蛋白(HSA)的相互作用。实验发现:Eu(Ⅲ)和Pr(Ⅲ)对HSA有较强的荧光猝灭作用。用Stern-Volmer方程分别对实验数据进行处理,结果发现:HSA与Eu(Ⅲ)、Pr(Ⅲ)发生反应生成了新的复合物,发生了分子内的非辐射能量转移。Eu(Ⅲ)、Pr(Ⅲ)对HAS的荧光猝灭作用,属于静态荧光猝灭。荧光猝灭图表明:Eu3+和Pr3+在HSA分子中至少有两类结合位点,Eu3+与HSA形成2.76∶1的复合物,结合常数lgK分别为12.03和9.05;Pr3+与HSA形成2.2∶1的复合物,结合常数lgK分别为9.89和6.97。同时用圆二色谱及同步荧光光谱法探讨了 Eu(Ⅲ)和Pr(Ⅲ)对HSA构象的影响。  相似文献   

8.
研究了纳米银对分别以水、重水、乙醇和二甲基甲酰胺为溶剂的铕-吡啶-2,6-二羧酸(Eu(Ⅲ)DPA)配合物溶液的荧光增强效应. 研究结果表明,Eu(Ⅲ)DPA溶液中加入纳米银,电偶极跃迁(5D07F2)和磁偶极跃迁(5D07F1)发射强度先增强而后逐渐下降,5D07F2的荧光增强效率高于5D07F1的荧光增强效率. 在乙醇溶剂中纳米银对Eu(Ⅲ)DPA溶液的荧光增强效应最大. 在水或重水或乙醇溶剂中,Eu(Ⅲ)DPA的不对称率明显提高,而在二甲基甲酰胺溶剂中几乎不变. 分析认为,纳米银对Eu(Ⅲ)DPA溶液荧光的影响与纳米银表面等离子体共振与激发态荧光中心强烈耦合以及表面等离子体再吸收有关.  相似文献   

9.
我们利用DFT中的B3LYP方法优化了Ru(Ⅱ)配合物和氧化的Ru(Ⅲ)配合物[Ru(bpy)(PH3)(-C≡CC6H4NO2-p)Cl]m[bpy=2,2′-bipyridine;m=0 (1),+1 (1+)]的基态几何结构,得到的几何参数与实验结果吻合的很好。采用TDDFT方法,得到了配合物11+的激发态电子结构和电子吸收光谱。研究结果表明,配合物11+随着氧化过程的发生,光谱性质也发生变化,Ru(Ⅱ)配合物的低能吸收被指认为MLCT/LLCT混合跃迁,而氧化的Ru(Ⅲ)配合物1+的低能吸收具有LMCT跃迁性质。  相似文献   

10.
合成了2个含肟基Schiff碱Cu(Ⅱ)配合物[Cu(L1)2](1)和[Cu(L2)2](2)(HL1=1-(3-((2-hydroxybenzylidene)amino) phenyl) ethanone O-benzyl oxime; HL2=1-(3-((2-Hydroxy-naphthalen-1-ylmethylene)-amino)-phenyl)-ethanone oxime),并通过元素分析、红外光谱、紫外光谱,荧光光谱及X射线单晶衍射分析进行了表征和分析。结果表明,配合物12具有相似的结构,均由1个中心Cu(Ⅱ)离子和2个双齿配体单元组成,且Cu(Ⅱ)离子的配位数为4,具有平面四边形结构。配合物12均形成了二维层状超分子结构,不同的是配合物1通过分子间ππ堆积作用相连接,而配合物2通过分子间O-H…N和C-H…π氢键作用而形成了超分子结构。进一步讨论了配合物1的荧光性质及两个配合物间配体的取代基效应。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

16.
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   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
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%).  相似文献   

19.
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   

20.
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.  相似文献   

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