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1.
Abstract— Absorption, fluorescence and phosphorescence spectra as well as fluorescence and phosphorescence quantum yields of 8-X-5-deazaflavins (X = C1, NO 2, p -NO 2-C 6H 4, N(CH 3) 2, NH 2, p -NH 2-C 6H 4, p -N(CH 3) 2-C 6H 4-N=N) were determined. It was found that all these data are highly influenced by the substituent at position 8 of the 5-deazaisoalloxazine skeleton. Also the photoreduction of 8-X-5-deazaflavins in the presence of electron donors was studied. It was established that the photoreduction leads to the formation of a 5,5'-dimer and/or a 6,7-dihydro compound. Reduction of the C(6)-C(7) bond is promoted by strong electron-donating substituents and bulky electron donors. 5-Deazaftavins with a reducible substituent at position 8 exhibit reduction of the substituent prior to the reduction of the 5-deazaisoalloxazine skeleton. 相似文献
2.
2(1H)-吡啶酮类化合物常呈现出诱人的生物活性[1,2].由于酮式和烯醇式结构具有互变异构化性质,因此确定其互变异构平衡体系中的优势结构及研究取代基对平衡体系的影响,对阐明该类化合物的生物活性及进行构效关系的研究有着重要的意义.当其3-位含有可与2-位羰基或2-位羟基形成分子内氢键的基团时,势必对互变异构平衡产生影响.基于该类化合物的互变异构平衡有着强烈的溶剂效应[3],本文对3-X-2(1H)-吡啶酮(X=NO2,NH2,COOH)及其烯醇式互变异构体分别在气相和溶液中进行了理论计算,考察了… 相似文献
3.
The mono- and bis-cyclopentadienyl compounds 1-(Cp″)-4-(CH 3)C 6H 4 (1) and 1, 4-(Cp″) 2C 6H 4 (2) (Cp″ = 3,4-dimethylcyclopenta-1,3-diene-1-yl) have been synthesized. The reactions of the lithium salts of 1 and 2 with CpZrCl 3 · dme (dme = dimethoxyethane) and Cp*ZrCl 3(CP* = C 5(CH 3) 5) yielded the mono- and bi-nuclear bridged zirconocenes 1-(Cp″ZrCpCl 2)-4-(CH 3)C 6H 4 (3), 1,4-(Cp″ZrCpCl 2) 2C 6H 4 (4) and 1,4-(Cp″ZrCp*Cl 2) 2C 6H 4 (5). When activated with methylaluminoxane (MAO), the mono- and bi-nuclear zirconocenes 3 and 4 catalyse the polymerization of propene. The influence of the catalyst composition on the polymerization kinetics and molecular weight is discussed. 相似文献
4.
采用化学浴(CBD)法在TiO 2薄膜表面制备结晶性Sb 2S 3膜层, 获得了TiO 2/Sb 2S 3平板异质结, 并结合聚[2,6-{4,4-双-(2-乙基己基)-4 H-环戊并[2,1-b;3,4-b']-二噻吩}-交替-4,7-(2,1,3-苯并噻二唑)](PCPDTBT)空穴传输层和MoO 3电极界面修饰层, 制备了FTO/TiO 2/Sb 2S 3/PCPDTBT/MoO 3/Au平板结构太阳能电池, 研究了CBD方法中热退火气氛对Sb 2S 3薄膜的组成、 结构及光伏性能的影响. 结果表明, 在N 2气氛下退火时, 所得的Sb 2S 3膜层不致密且含有Sb 2O 3杂相, 电池效率仅为0.90%; 而在N 2-S气氛下退火时, 硫会与杂相Sb 2O 3发生反应生成Sb 2S 3, 进而得到纯净、 致密、 平整的结晶Sb 2S 3膜层. 在平板结构太阳能电池中, 光生空穴对电池光电流的产生有明显的贡献; 随着Sb 2O 3杂相的消除, Sb 2S 3薄膜中载流子的复合减少且传输速率增大, 使太阳能电池器件中电子与空穴的收集效率和短路电流显著提高, 电池效率提高了1.34倍, 达到2.04%. 相似文献
5.
A series of heterocyclic compounds of triazole thione substituted by tetrazole(I)were prepared using nicotinic acid as starting material through several steps.They reacted with 1-O-trifluoroacety1-2,3,5-O-tri-benxoyl-β-D-ribofuranose(Ⅱ) inanhydrous CH 2Cl 2 at room temperature in the presence of BF 3·Et 2O to give nine new nucleosides, named as 3-[5-(3-pyridyl)-tetrazol-2-yl-methylene]-4-aryl,2,4-triazole-5-(4H)-thione-2, 3, 5-O-tribenwyl-β-D-ribo-furanoside(Ⅲ)(Ar=C 6H 5,o-MeC 6H 4,m-MeC 6H 4,p-MeC 6H 4,o-MeC 6H 4,p-MeC 6H 4,p-EtOC 6H 3,3,4-Me 2C 6H 4,a-C 10H 7).The structures and compositions were characterized by means of elemental analysis and spectroscopic methods. 相似文献
6.
CpIr(η 4-C 6H 6) (2) has been obtained in high yield by a four-step synthesis. Thermal reaction of 2 with CpCO(C 2H 4) 2 and photochemical reaction of 2 with CpRh(C 2H 4) 2 or CpRh(C 2H 4) 2 give the compounds μ-(η 3: η 3-C 6H 6)CoIrCp 2 (3), μ-(η 3: η 3-C 6H 6)RhIrCp 2 (4), and μ-(η 3: η 3-C 6H 6)(RhCp)(IrCp) (5), respectively. The X-ray crystallography data of 3 and 4 reveal a boat-shaped conformation of the synfacially bridging benzene ligand with a rather long Co---Ir bond distance in 3 and a relatively short Rh---Ir bond length in 4 which are caused by almost constant folding angles of the benzene unit. The dynamic behaviour of the benzene bridge was investigated by NMR spectrometry. 相似文献
7.
4,4′-二溴联苯与n-BuLi反应得到对-联苯基二锂,再与四甲基环戊烯酮进行羰基加成,酸催化脱水,一步得到对-联苯基桥连四甲基环戊二烯配体4-(C 5Me 4H)C 6H 4-C 6H 4(C 5Me 4H)-4(1).配体1相继与n-BuLi和ZrCl 4反应得到相应的联苯基桥连双(单茂三氯化锆)4-(C 5Me 4ZrCl 3)C 6H 4-C 6H 4(C 5Me 4ZrCl 3)-4,不经分离直接与环戊二烯基锂或茚基锂反应得到相应的双核锆化合物4-(C 5MeZrCl 2Cp′)C 6H 4-C 6H 4·(C 5Me 4ZrCl 2Cp′)-4[Cp′=C 5H 5(2),C 9H 7(3)].研究了在MAO(MethylAluminoxane)助催化下,化合物2和3对乙烯聚合的催化性能.化合物2和3都显示了非常高的催化活性,并在较高的温度下达到最高活性. 相似文献
8.
The substitution reactions of XC 6H 4COCl [X=2-, 3-, or 4-CH 3; 2-, 3-, or 4-CH 3O; 2-, or 4-I; or 2-, 3-, or 4-NO 2] and YC 6H 4COONa [Y=2-, 3-, or 4-CH 3; 2-, 3-, or 4-CH 3O; 2-I; 4-NO 2; or H] in a two-phase H 2O/CH 2Cl 2 medium using pyridine-1-oxide (PNO) as an inverse phase transfer catalyst were investigated. In general, the kinetics of the reaction follows a pseudo-first-order rate law, with the observed rate constant being a linear function of the concentration of PNO in the water phase. In contrast to other analogous reactions, the hydrolysis reaction of 2-, 3-, or 4-NO 2C 6H 4COCl in H 2O/CH 2Cl 2 medium is catalyzed considerably by PNO and reaches an equilibrium. In the PNO-catalyzed reaction of XC 6H 4COCl and XC 6H 4COONa in H 2O/CH 2Cl 2 medium, the order of reactivities of XC 6H 4COCl toward reaction with PNO in CH 2Cl 2 is 2-IC 6H 4COCl>4-IC 6H 4COCl>(C 6H 5COCl,3-CH 3OC 6H 4COCl)>3-CH 3C 6H 4COCl>(2-CH 3C 6H 4COCl,4-CH 3C 6H 4COCl)>4-CH 3OC 6H 4COCl>2-CH 3OC 6H 4COCl. Combined with the results of other analogous reactions, good Hammett correlations with positive reaction constant were obtained for the meta- and para-substituents, which supports that the XC 6H 4COCl–PNO reaction in CH 2Cl 2 is a nucleophilic substitution reaction. 相似文献
9.
The preparation and properties as well as some reactions of a series of arylcarbonylbis(triphenylphosphine)iridium(I) complexes [Ir(Ar)(CO)(PPh 3) 2] (Ar = C 6H 5, C 6F 5, 2-C 6H 4CH 3, 3-C 6H 4CH 3, 4-C 6H 4CH 3, 2-C 6H 4OCH 3, 2,6-C 6H 3-(OCH 3) 2, 4-C 6H 4N(CH 3) 2, 3-C 6H 4Cl, 4-C 6H 4Cl, 4-C 6H 4Cl, 3-C 6H 4CF 3, 4-C 6H 4CF 3) are described, and the most important IR data as well as the 31P NMR parameters of these, without exception trans-planar, compounds are given. Some of the complexes react with molecular oxygen to form well defined dioxygen adducts [Ir(Ar)(O2)(CO)(PPh3)2] (Ar = C6H5, 3-C6H4CH3, 4-C6H4CH3). Complexes with ortho-substituted aryl ligands are not oxygenated. This effect is referred to as a steric shielding of the metal center by the corresponding ortho-substituents. With SO2 the similar irreversible addition compound [Ir(4-C6H4CH3)-(SO2)(CO)(PPh3)2] is obtained. Sulfur dioxide insertion into the Ir---C bond cannot be observed. The first step of the reaction between [Ir(4-C6H4CH3)(CO)(PPh3)2] and hydrogen chloride involves an oxidative addition of HCl to give [Ir(H)(Cl)(4-C6-H4CH3)(CO)(PPh3)2]. Ir---C bond cleavage by reductive elimination of toluene from the primary adduct does not occur except at elevated temperature. 相似文献
10.
通过水热反应合成了Sb 2WO 6改性的g-C 3N 4复合材料(Sb 2WO 6 /g-C 3N 4). 通过X射线衍射(XRD)、 扫描电子显微镜(SEM)、 紫外-可见漫散射反射光谱(UV-Vis DRS)和光致发光光谱(PL)等表征了样品的性质. 结果表明, Sb 2WO 6在g-C 3N 4的表面上生长, 并且复合材料光吸收能力有一定的增强, 光生电子-空穴的重组率降低. 通过罗丹明B(RhB)的光降解评价了Sb 2WO 6/g-C 3N 4复合材料的光催化性能. 结果表明, 模拟日光下Sb 2WO 6质量分数为10%的Sb 2WO 6/g-C 3N 4复合材料在60 min内对RhB的降解率为99.3%, 高于纯g-C 3N 4和Sb 2WO 6. Sb 2WO 6/g-C 3N 4复合材料的这种高度增强的光催化活性主要归因于强的界面相互作用促进了光生电子-空穴分离和迁移. 添加自由基清除剂的实验结果表明, ·O 2-和h +是光催化反应中的主要活性物质. Sb 2WO 6/g-C 3N 4复合材料在几个反应周期内表现出优异的稳定性. 根据实验结果提出了一种可能的Z型光催化机理. 相似文献
11.
Two organogold derivatives of diphenylmethane and diphenylethane, Ph 3PAu( o-C 6H 4)CH 2(C 6H 4- o)AuPPh 3 (1) and Ph 3PAu( o-C 6H 4)(CH 2) 2(C 6H 4- o)AuPPh 3 (2), have been synthesized by the reaction of ClAuPPh 3 with Li( o-C 6H 4)CH 2(C 6H 4- o)Li and Li( o-C 6H 4)(CH 2) 2(C 6H 4- o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh 3 groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph 3PAu]BF 4 to form new types of cationic complex [CH 2(C 6H 4- o) 2(AuPPh 3) 3]BF 4 (4), [CH 2(C 6H 4- o) 2(AuPPh 3) 4](BF 4) 2 (5), and [(CH 2) 2(C 6H 4- o) 2(AuPPh 3) 4](BF 4) 2 (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by 1H and 31P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH 2— and CH 2-CH 2—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6. 相似文献
12.
Reaction of [Cp *TiF 3] (Cp * = (ν 5-C 5Me 5)) with Me 3SiOSO 2- p-C 6H 4CH 3, Me 3SiOPOPh 2 and 1,2-(Me 3SiOCO) 2C 6H 4 yields the dinuclear complexes [{Cp *TiF(μ-F)(μ-OSO 2- p-C 6H 4CH 4)} 2] (1), [{Cp *TiF(μ-F)(μ-OPOPh 2)} 2] (2) and [{Cp *TiF(μ-F)(μ-OCO- o-C 6H 4CO 2SiMe 3)} 2] (3). The molecular structures of 1 and 2 have been determined by single-crystal X-ray analysis. In complexes 1-3, the two titanium atoms are connected by bridging fluorine atoms as well as bridging sulfonate, phosphinate and carboxylate groups respectively. Each titanium atom is also bonded to a terminal fluorine atom. Reaction of [Cp 2*ZrF 2] with 1,2-(Me 3SiOCO) 2C 6H 4 leads to the mononuclear pentacoordinate 18-electron species [Cp 2*ZrF(μ-OCO- o-C 6H 4CO 2SiMe 3)] (4) and its structure was determined by X-ray crystallographic methods. 相似文献
13.
In order to investigate the influence of organic groups on the types of organoarsenic polymolybdates, the reations of p-aminophenylarsonic acid with sodium molybdate were tested at pH=3-5. Six salts were prepared and characterized. (1) (CN3H8)4 [(p-NH3C6H4As)2Mo6O25] · H2O, (2) (CN3H6)4 [(p-, NH3C6H4As )2Mo6O25 ] · 6H20, (3) Cs4 [(p-NH3C6H4As)2Mo6O25] · 4H2O, (4) C(CH3)4N]4[(p-NH3C6H4As)2Mo6O25] · 5H2O, (5) [(n-C4H9)4N]3Na[(p-NH3C6H4As)2Mo6O25] · 2H2O, (6) Ba2 NH3C6H4As)2Mo6O25] · 10H2O. The IR, UV spectra, and electrochemical behavior are reported and discussed. They should belong to the same type as that for phenyl derivative or the nitrophenyl derivatives. But the ammo groups can accept protons, so that the anion' s charge decreases. Very similar to the tungsten congener (CN3H6)4[(p-NH3C,H4As)2W6O25] · 4H2O, [(RAs)2Mo6O25]4- type of complexes are formed. 相似文献
14.
Liquid crystalline 4-XC 6H 4N=NC 6H 4X-4′ [X = C 4H 9 (1a), C 1OH 21 (1b), OC 4H 9 (1c), OC 8H 17(1d)] can be easily prepared in high yields from the corresponding anilines. In order to study the influence of metals on the thermal properties of these materials, we have obtained adducts [AuCl 3(4-C 4H 9OC 6H 4N=NC 6H 4OC 4H 9-4′)] (2) and [Ag(OC1O 3)L 2] [L = 4-XC 6H 4N=NC 6H 4X-4′; X = OC 4H, (3a), OC 8H 17 (3b)]. The silver adducts show themotropic behaviour. Mercuriation of dialkylazobenzenes 1a-b takes place with [Hg(OAc) 2] and LiCl to give [Hg(R)Cl] [R = C 6H 3(N=NC 6H 4X-4′)-2, X-5; X = C 4H 9 (bpap) (4a), C 10H 21 (dpap) (4b)] while dialkoxyazobenzenes 1c–d require [Hg (OOCCF 3) 2] to obtain [Hg(R)Cl] [R = C 6H 3(N---NC 6H 4X-4′)-2, X-5; X = OC 4H 9 (bxpap) (4c), OC 8H 17 (4d)]. 4a-c react with NaI to give [HgR 2] [R= bpap (5a), dpap (5b), bxpap (5c), oxpap (5d)l. Both chloroaryl-, 4a and 4c, and diaryl-mercurials, 5a and 5c, act readily as transmetailating agents towards [Me 4N] [AuCl 4] in the presence of [Me 4N]Cl to give [Au(η 2-R)Cl 2] [R = bpap (6a), bxpap (6b)]. After reaction of [AuCl 3(tht)] (tht = tetrahydrothiophene) with [Me 4N]Cl and 4b (1:2:1), [Me 4N][Au(dpap)Cl 3] (7) can be isolated. C---H activati bxpap (8b)]. None of the complexes 4–8 shows mesomorphic behaviour. 相似文献
15.
The synthesis of the new (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,3-(C 6H 4X) ( m-2a/2b; X=F/Br) and (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4I) (2c) complexes, as well as the solid-state structure of the known (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4F) (2a) complex are described. The catalytic coupling reactions of the bromo complexes with various alkynes were next investigated. Starting from the known (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4Br) complex (2b), the synthesis of the (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4)---CC---H complex (6d) and of the corresponding silyl-protected precursors (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4)CC---SiR 3 (6b/6c; R= iPr/Me) are reported. By use of lithium---bromine exchange reactions on 2b, the silyl- (7a; E=Si; R=Me) and tin- (7b–7d; E=Sn; R=Me, Bu, Ph) substituted analogues (η 2-dppe)(η 5-C 5Me 5)Fe---CC---1,4-(C 6H 4)ER 3 are also isolated. The spectroscopic and electrochemical characterisations of all these new Fe(II)/Fe(III) redox-active building blocks are presented and the electronic substituent parameters for the “(η 2-dppe)(η 5-C 5Me 5)Fe---CC” group are determined by means of 19F-NMR. 相似文献
16.
由混合二烃基二氯化锡与水杨醛缩苯胺类Schiff碱反应,合成了24种新的有机锡配合物。经元素分析、NMR、TG-DSC测定和X射线粉末衍射分析,确定有14种是有机锡与Schiff碱的1:1配合物,10种是1:2配合物。配体是以酚羟基氧原子与锡原子配位,摩尔电导率测定表明这些配合物均为非电解质。 相似文献
17.
The reaction of the metallocene dichlorides Cp 2MCl 2 (Cp = η 5-C 5H 5; M = Ti, Zr, Hf, Mo, W) and Cp 2′TiCl 2 (Cp′ = η 5-C 5H 4CH 3) with equimolar amounts of dilithium-benzene- o-diselenolate, 1,2-(LiSe) 2C 6H 4, gives the chelate complexes Cp 2M(Se 2C 6H 4) (M = Ti (I), Zr (II), Hf (III), Mo (IV), W (V)) and Cp 2′Ti(Se 2C 6H 4) (VI). CpTiCl 3 reacts with 1,2-(LiSe) 2C 6H 4 to give CpTiCl(Se 2C 6H 4) (VII). The ring inversion activation parameters for I–VI can be determined by means of temperature-dependent 1H NMR spectroscopy in solution. The fragmentation behaviour of I–VII in the mass spectrometer has been investigated by pursuing metastable transitions, using linked-scan techniques. 相似文献
18.
采用激光拉曼光谱(LRS)技术对添加有乙二醇和柠檬酸的NiMoP浸渍液和用该浸渍液制备的NiMoP/Al 2O 3催化剂进行了表征,研究了乙二醇和柠檬酸含量对NiMoP浸渍液及浸渍过程中活性相组成、结构的影响。结果表明,乙二醇使NiMoP(0.063)浸渍液中H x\[PMo11O39\](7-x)- 或Hx\[PMo9O31\](3-x)-及Hx\[PMo12O40\](3-x)- 杂多阴离子结构转化成Hx\[P2Mo5O23\](6-x)- 结构,而柠檬酸能保持NiMoP(0.063)浸渍液中Hx\[P2Mo5O23\](6-x)-、Hx\[PMo11O39\](7-x)- 或Hx\[PMo9O31\](3-x)-及Hx\[PMo12O40\](3-x)-杂多阴离子结构共存,但导致Hx\[P2Mo5O23\](6-x)-含量降低,Hx\[PMo12O40\](3-x)-含量升高。相对乙二醇而言,柠檬酸有机添加剂能够更有效地阻止浸渍过程中各杂多阴离子结构在载体氧化铝孔道中的分解。 相似文献
19.
[W 3Se 7(S 2P(OEt) 2) 3]Br was prepared by reacting (Et 4N) 2W 3Se 7Br 6 with KS 2P (OEt) 2 in CH 3CN and its crystal structure determined. In the [W 3(μ 3-Se)(μ 2-Se 2) 3] 4+ core the W---W bond length is 2.755(5)-2.764(6) Å and the Se---Se bond length is 2.32(1)- 2.34(4) Å. 相似文献
20.
Distibines of the type R 2SbSbR′ 2 with R = CH 3, R′ = C 2H 5 (1), R = CH 3, R′= n-C 3H 7 (2), R = CH 3, R′= C 6H 5 (3), R = C 2H 5, R′= C 6H 5 (4), R = n-C 3H 7, R′ = C 6H 5 (5), and R = CH 3, R′ = 2,4,6-(CH 3) 2C 6H 2 (6) are formed in equilibria by exchange reactions of the respective distibines of the type R 4Sb 2 and R′ 4Sb 2. 相似文献
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