60 resultados para PTP-1B


Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正> 葡萄藻作为一种新的再生性能源的研究,已引起了不少学者的重视。其中较为关键的是对葡萄藻所含脂类物质的研究。过去通常采用重量法及各类色谱法测定植物中的脂类物质。这些方法不但繁琐,而且均需一个较长时间的提取过程。近年来国外采用一种新型染料——尼罗

Relevância:

10.00% 10.00%

Publicador:

Resumo:

When tobacco BY-2 cells were treated with 60 mu g/mL MC-RR for 5 d, time-dependent effects of MC-RR on the cells were observed. Morphological changes such as abnormal elongation, evident chromatin condensation and margination, fragmentation of nucleus and formation of apoptotic-like bodies suggest that 60 mu g/mL MC-RR induced rapid apoptosis in tobacco BY-2 cells. Moreover, there was a significant and rapid increase of ROS level before the loss of mitochondrial membrane potential (Delta Psi(m)) and the onset of cell apoptosis. Ascorbic acid (AsA), a major primary antioxidant, prevented the increase of ROS generation, blocked the decrease in Delta Psi(m) and subsequent cell apoptosis, indicating a critical role of ROS in serving as an important signaling molecule by causing a reduction of Delta Psi(m) and MC-RR-induced tobacco BY-2 cell apoptosis. In addition, a specific mitochondrial permeability transition pores (PTP) inhibitor, cyclosporin A (CsA), significantly blocked the MC-RR-induced ROS formation, loss of Delta Psi(m), as well as cell apoptosis when the cells were MC-RR stressed for 3 d, suggesting that PTP is involved in 60 mu g/mL MC-RR-induced tobacco cell apoptosis signalling process. Thus, we concluded that the mechanism of MC-RR-induced apoptosis signalling pathways in tobacco BY-2 cells involves not only the excess generation of ROS and oxidative stress, but also the opening of PTP inducing loss of mitochondrial membrane potential. (C) 2007 Published by Elsevier Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new unsymmetrical photochromic diarylethene 1a is synthesized, and the photochromic properties of it are also investigated. The compound exhibits good photochromism with UV/ visible light irradiation. Compound 1a in polymethyl methacrylate ( PMMA ) film changes color upon 313- nm light irradiation from colorless to blue, in which the absorption maximum is observed at 587 nm. Photon- mode polarization multiplexing holographic optical recording is performed successfully using this compound as a recording medium. In the diarylethene 1b/ PMMA film, polarization multiplexing hologram recording and retrieval, and a combination with the angular multiplexing scheme, are demonstrated systematically. The results indicate that recording capacity can be significantly improved with the combined method of polarization and angular multiplexing holographic recording. (C) 2008 Society of Photo- Optical Instrumentation Engineers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本论文探讨了烯烃聚合催化剂的合成及其用于聚合的研究,合成的催化剂是不含桥基的IVB族的茂金属化合物。共合成了十九个茂金属化合物:(~tBuC_5H_4)CpMCl_2[M=Ti(1a),Zr(1b)]; Me_3SiC_5H_4CpMCl_2[M=Ti(2a), Zr(2b)];~tBu_2C_5H_3CpMCl_2[M=Ti(3a),Zr(3b)];C_5H_9IndCpMCl_2[M=Ti(4a),Zr(4b)];PhCH_2IndCpMCl_2[M=Ti(5a),Zr(5b)];(~tBu_2C_5H_3)_2MCl~2[M=Ti(6a),Zr(6b),Hf(6c)];(C_5H_9Ind)_2MCl_2[M=Ti(7a),Zr(7b),Hf(7c)];(PhCH_2C_6H_5)_2MCl_2[M=Ti(8a),Zr(8b),Hf(8c)]。这十九个化合物分别通过EI-MS,~1H-NMR,IR 和元素分析进行了表征。用所合成的十九种茂金属化合物与甲基铝氧烷作为催化体系,在常温常压下,研究了乙烯聚合反应。得到的主要结论如下:(1)1a,2a, 5b 8b 催化活性最好。(2)1a 在铝钛比等于 1167 时聚合效率最高,2a 在铝钛比等于 1500 时聚合效率最高, 5b 在铝锆比大于 2955 时聚合效率最高,8b 在铝锆比等于 1667 时聚合效率最高。(3)相同的聚合条件下,催化效率是 1a<2a,8b<5b。(4)由聚合物的DSC表征中可见,所得聚合物的结晶度是 1a<2a,5b>8b。(5)由聚合物的分子量的测定可知,所得聚合物的分子量是 1a>2a ,5b<8b,由 8b 催化得到的聚合物的分子量最大。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

干扰素(IFNs)是最早发现的具有广泛用途的一类细胞因子,IFN-α通过JAK/STAT信号途径调控机体一系列生理和病理反应。至今尚未发现类干扰素的小分子。我们前期研究发现天然产物毛蕊异黄酮可激活干扰素诱导的JAK/STAT信号途径。为发现类干扰素小分子、获得小分子探针,本课题拟建立成熟的JAK/STAT信号途径的筛选模型,合成毛蕊异黄酮及其类似物,研究这些化合物的构效关系,进而尝试通过共价键标记生物素或香豆素来直接研究它们与相关受体的作用。 从异香草醛出发经7步合成反应得到了毛蕊异黄酮。采用平行合成策略得到异黄酮类化合物;采用分支式合成策略,以取代苯乙酸作为合成砌块,获得具有与异黄酮类似结构的香豆素、3-芳基喹诺酮。与分离得到的黄酮类化合物,构建了一个包括异黄酮、黄酮、香豆素、3-芳基喹诺酮在内的化合物库。 建立了包含IFN-α刺激反应元件 (ISRE)的荧光素酶报告基因体系,通过筛选化合物库中的化合物,发现异黄酮骨架为激活JAK/STAT信号途径必须结构、毛蕊异黄酮7-位酚羟基被取代后活性丧失。根据以上结果,对毛蕊异黄酮3′-位标记物的合成进行了初步尝试。 发现山茱萸科植物青荚叶(Helwingia japonica (Thunb.) Dietr.)有抑制蛋白酪氨酸磷酸酯酶1B(PTP1B)的活性。从其地上部分95%乙醇提取物的乙酸乙酯部分分离得到5个化合物,应用波谱方法及与已知品对照的手段鉴定它们为p-menth-2-en-1β, 4β, 8-triol (Z-1)、blumenol A (Z-2)、2′,3′,4′,5′,6′-五羟基查尔酮(Z-3)、洋芹素7-O-β-D-吡喃葡萄糖苷(Z-4)、木犀草素7-O-β-D-吡喃葡萄糖苷(Z-5). Interferons (IFNs) are one kind of cytokines with broad functions. IFN-α mediates series physiological and pathological changes of human body via JAK/STAT pathway. Untill now, no IFNs-like small molecules are discovered. In our preliminary experiment, the natural product calycosin has been observed to activate JAK/STAT pathway. Therefore, we establish a luciferase reporter gene system and synthesize calycosin and its analogues to reveal their structure-activity relationship (SAR). Besides, in order to prove that calycosin activates JAK/STAT pathway through IFN receptor, we attempted to tag it with biotin or coumarin by covalent bonding. Calycosin was synthesized from isovanillin via seven steps. Other isoflavones were obtained by parallel synthesis; coumarins and quinolones were prepared through divergent synthesis, using substituted phenylacetic acids as building blocks. Combing with natural flavones, a small molecule library was established. A luciferase reporter gene system, consisting of 5 copies of the ISRE (interferon-stimulated response element), was used for screening of small molecules from that library. We found that the core-structure of isoflavone was necessary, and if the 7-OH is substituted, the activity slumps. According to our observation, we tried to tag biotin or coumarin at 3′-OH of calycosin. The 95% ethanol extract of the aerial parts of Helwingia japonica (Thunb.) Dietr. showed protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Five compounds were isolated. On the basis of spectral data or by comparison with authentic samples, they were identified as p-menth-2-en-1β,4β,8-triol (1), blumenol A (2), 2′,3′,4′,5′,6′-pentahydroxychalcone (3), apigenin 7-O-β-D-glucopyranoside (4), and luteolin 7-O-β-D-glucopyranoside (5).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本论文由三章组成。第一章阐述了藏药水菖蒲的化学成分研究,共分离鉴定了39个化学成分,其中6个为新化合物。第二章报道了几种忍冬属植物的HPLC、HPLC-MS、GC分析以及抑菌活性、重金属含量测定结果。第三章概述了菖蒲属植物的研究进展。 第一章报道了水菖蒲(Acorus calamus L.)化学成分的分离纯化与结构鉴定。采用正、反相硅胶柱层析等分离方法,从水菖蒲的根中共分离出41个化合物,通过红外、质谱、核磁共振及X-ray单晶衍射等波谱方法和模拟计算方法鉴定了其中39个化合物的结构,主要为倍半萜、苯丙素、甾体类化合物。其中含有5个新的倍半萜类化合物和1系列新的甾体皂苷衍生物。经波谱分析将它们的结构鉴定为 1b, 7a(H)-cadinane-4a, 6a, 10a-triol (1), (2R,6R,7S,9S)-1(10), 4-cadinadiene-2, 9-diol (2), 1a, 5b-guaiane-10a-O-ethyl-4b, 6b-diol (7), 6b, 7b(H)-cadinane-1a, 4a, 10a-triol (13),(1R,4R,6S,10R)-1-hydroxy-7(11)-cadinen-5, 8-dione (14), 4′-O-正n碳酰基-3-O- β-D-葡萄糖基谷甾醇(n=14, 16, 18, 22) (15)。 第二章包括四个部分。第一部分报道了忍冬属三种植物40个样品的HPLC测定和对主要活性成分绿原酸的定量分析结果,以及运用HPLC-MS技术对色谱图中8个峰进行指认。在此基础上,考察了种植和采收多个因素对绿原酸含量的影响。第二部分报道了忍冬属三种植物27个样品的GC分析,根据样品的挥发性成分的保留时间对不同样品进行了定性比较,并考察了花期及海拔高度对植物挥发性成分的影响。第三、四部分分别阐述了灰毡毛忍冬和红腺忍冬的体外抑菌活性研究和重金属含量测定结果。 第三章全面系统地概述了菖蒲属植物的化学成分和药理活性研究进展。 This dissertation is composed by three chapters. The first chapter elaborates the phytochemical investigation of Acorus calamus L. Thirty-nine compounds including six new compounds were isolated and identified. The second chapter reports the research on genus Lonicera by HPLC, HPLC-MS and GC. Antifungal activity and heavy metals measurement of genus Lonicera were reported. The third chapter is a review about the research progress on the plant family of Acorus. The first chapter focuses on the isolation and identification of chemical constituents from Acorus calamus L.. Forty-one compounds were isolated from the root of Acorus calamus L. by repeat column chromatography over normal and reversed phase silica gel, the structure of thirty-nine compounds was identified by spectroscopic methods and computational methods, including IR, MS, NMR and X-ray. Those compounds mainly belonged to sesquiterpene, phenylpropanoid and steroid. Among them, five are new sesquiterpenes and one series are new steroid glycoside derivatives. Their structure were suggested as 1b, 7a(H)-cadinane-4a, 6a, 10a-triol (1), (2R,6R,7S,9S)-1(10), 4-cadinadiene-2, 9-diol (2), 1a, 5b-guaiane-10a-O-ethyl-4b, 6b- diol (7), 6b, 7b(H)-cadinane-1a, 4a, 10a-triol (13), (1R,4R,6S,10R)-1-hydroxy-7(11)- cadinen-5, 8-dione (14), 4′-O-carbonyl-3-O-β-D-glucosyl-sitosterol (carbonyl = tetradecanoyl, hexadecanoyl, octadecyl, docosanoyl) (15). The second chapter consists of four parts. The first part reports the HPLC analysis of forty samples of the genus Lonicera, and the quantitative investigation of chlorogenic acid in these samples by HPLC analysis. Relationship between the content of chlorogenic acid in different samples and their planting conditions and harvesting time were discussed. Furthermore, eight compounds were identified or tentatively characterized based on their mass spectra and UV spectra profiles. The second part is about qualitative analysis of the volatile constituent in twenty-seven samples of genus Lonicera by GC. The effect of planting altitude and harvesting time on the volatile constituent was also investigated. The third and fourth parts describe the antifungal activity and content of some kinds of heavy metals of L. macranthoides Hand.-Mazz. and L. hypoglauca Miq.. The third chaspter is a review about the research progress of the plant family of Acorus.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本研究对自育小麦白粉病抗源“07鉴126”和条锈病抗源CD1437、CD0534-5进行抗性遗传分析和微卫星引物的筛选,建立了与PmCD1和YrCD抗病基因连锁的SSR分子标记,主要研究结果如下: 1.小麦白粉抗源“07鉴126”抗白粉病基因的鉴定和分子标记的建立 品系“07鉴126”对我国目前白粉菌强优势生理小种E09、E11和其它多种小种表现免疫或高度抵抗。Pm-sus是07鉴126的自然突变感病株。利用“07鉴126”和Pm-sus的F2抗病性分离群体进行抗条锈病性遗传分析和分子标记定位,结果表明,“07鉴126”的白粉抗性为显性单基因控制的全生育期抗性,暂命名为PmCD1;并筛选到了与PmCD1共分离的显性SSR分子标记Xbarc183。系谱分析和分子标记分析表明PmCD1来源于荆州黑麦。抗谱分析表明PmCD1不同于已知的黑麦抗白粉基因,是一个新的抗白粉病基因。Xbarc183这一分子标记的建立为PmCD1的分子标记辅助选择和抗病基因累加提供了方便。 2.小麦条锈抗源CD1437抗条锈病基因的鉴定和分子标记的建立 利用对优势条锈菌小种条中32免疫的小麦品系CD1437及其自然突变感病株Yr-sus杂交构建F2、F3抗病性分离群体。抗条锈病性遗传分析结果显示,1437的抗条锈性为显性单基因控制的全生育期抗性,该基因暂命名为YrCD。SSR分析发现,位于1B染色体上的7个SSR标记Xcfd65、Xgwm11、Xgwm18、Xbarc187、Xwmc406、 Xwmc419、Xwmc216依次分布在YrCD的一侧,与YrCD的遗传距离在1.7 cM至9.2 cM。YrCD和YrCH42的等位性分析显示二者可能为等位基因。YrCD和Yr24、Yr26的抗谱相似。系谱分析和分子标记分析表明贵农20是YrCD的供体。本研究推测YrCD、Yr24、Yr26和YrCH42可能是等位基因,并推测Yr-sus是缺失突变体。 3. 小麦条锈抗源CD0534-5抗条锈病基因的鉴定 利用对条中32免疫的小麦抗条锈病品系CD0534-5及其感病重组自交系CD0534-4建立F2抗病性分离群体。抗条锈病性遗传分析表明,CD0534-5的条锈抗性由两对独立的显性主效基因控制。用BSK法分析,发现其中一对基因与SSR分子标记Xgwm11、Xgwm18、Xwmc128、Xwmc419连锁,该基因是来源于贵农20的YrCD。另一抗性基因来源贵农19,是极有利用价值的未知抗性基因。 This study focused on the investigation and identification of a novel powdery mildew resistant gene PmCD1 in wheat lines 07jian126 and stripe rust resistant gene YrCD in wheat lines CD1482 and CD0534-5, and screened SSR markers tightly linked to them. The main results were as follows: 1.Identification and SSR markers screening of a novel powdery mildew PmCD1 in wheat line 07jian126. Using a Pm resistant wheat line 07jian126 and its Pm susceptible mutant, a F2 population was constructed. Pedigree and genetic analyses indicated that the Pm resistance in 07jian126 was tranderred from rye (Secale cereale L.) cv. Jinzhou and was controlled by a single dominant gene. Differential test using 21 Bgt isolates revealed that the Pm resistant gene in 07jian126 is novel and was temporarily designated as PmCD1. A dominant SSR marker Xbarc183/130 bp was found co-segregated with PmCD1 in the F2 population. The diagnostic band of Xbarc183/130 bp co-segregating with PmCD1 could be used as an ideal marker in marker-assisted-selection during wheat breeding program. 2. Identification and SSR markers mapping of yellow rust resistant gene YrCD in wheat line CD1437. Wheat line CD1437 was highly resistant to predominant Chinese stripe rust race CYR32 at both seedling and adult stages. A F2 population was developed from the cross of CD1437 and its Yr susceptible mutant Yr-sus. Genetic analysis indicated line CD1437 contains a single dominant gene, temporarily designated YrCD. Seven SSR markers on the chromosome 1BS including Xcfd65, Xgwm11, Xgwm18, Xbarc187, wmc406, Xwmc419and Xwmc216 were close linked to YrCD with a genetic dsitance 1.7 cM to 9.2 cM. YrCD came from wheat cultivar Guinong 20. Allelic test of CD1437 and Chinese cultivar Chuanmai 42 indicated that YrCD and YrCH42 were allelic. Reaction patterns of YrCD and Yr24, Yr26 to 21 PST isolates were the same. These results suggested that YrCD and Yr24, Yr26, YrCH42 might be allelic. 3.Detection and identification of yellow rust resistance genes in wheat line CD0534-5 Wheat line CD0534-5 was highly resistant to predominant Chinese stripe rust race CYR32, while its recombinant inbred line CD0534-4 was susceptible. Genetic analysis with a F2 population developed from the cross of CD0534-5 and CD0534-4 indicated line CD0534-5 contains two independent dominant genes. Four SSR markers on the chromosome 1BS including Xgwm11, Xgwm18, Xwmc128, Xwmc419 were found to linked with one gene in CD0534-5. According the locations of makers and pedigree, this gene in CD0534-5 was YrCD, from cultivar Guinong 20. Another resistant gene was from cultivar Guinong 19, different with those genes on 1B such as Yr10, Yr15, Yr5 etc, was a valuable resistant gene in wheat breeding.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Chiral ferrocene-based phosphine-imine ligands 1-3 and sulfur-imine ligand 4 were applied in the palladium-catalyzed asymmetric allylic alkylation of cycloalkenyl esters. The results revealed that the substitutents in aryl ring, ferrocenylmethyl and benzyliene position strongly affected the enantioselective induction of phosphine-imine ligands, and the most stereoselective ligand was ferrocenylphosphine-imine 1b with a nitro group in the meta-position of phenyl ring. Under the optimized condition, up to 91% (enantiomeric excesses) e.e. of cyclic alkylation product was obtained by the use of 1b. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hydrogenolysis of mono(cyclopentadienyl)-ligated rare-earth-metal bis(alkyl) complexes Cp'Ln-(CH2SiMe3)2(THF) (Ln = Y (1a), Dy (1b), Lu (1c); Cp' = C5Me4SiMe3) with PhSiH3 afforded the mixed hydride/alkyl complexes [Cp'Ln(mu-H)(CH2SiMe3)(THF)](2) (Ln = Y (2a), Dy (2b), Lu (2c)). The overall structure of complexes 2a-c is a C-2-symmetric dimer containing a planar symmetric Ln(2)H(2) core at the center of the molecule. Deprotonation of ArOH (Ar = C6H2-Bu-t(2)-2,6-Me-4) by the metal alkyl group of 2a-c led to formation of the mixed hydride/aryloxide derivatives [Cp'Ln(mu-H)(OAr)](2) (Ln = Y (3a), Dy (3b), Lu (3c)), which adopt the dimeric structure through hydride bridges with trans-accommodated terminal aryloxide groups.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The syntheses of several dialkyl complexes based on rare-earth metal were described. Three beta-diimine compounds with varying N-aryl substituents (HL1 = (2-CH3O(C6H4))N=C(CH3)CH=C(CH3)NH(2-CH3O(C6H4)), HL2 = (2,4,6-(CH3)(3) (C6H2))N=C(CH3)CH=C(CH3)NH(2,4,6-(CH3)(3)(C6H2)), HL3 = PhN=C(CH3)CH(CH3) NHPh) were treated with Ln(CH2SiMe3)(3)(THF)(2) to give dialkyl complexes L(1)Ln (CH2SiMe3)(2) (Ln = Y (1a), Lu (1b), Sc (1c)), L(2)Ln(CH2SiMe3)(2)(THF) (Ln = Y (2a), Lu (2b)), and (LLu)-Lu-3(CH2SiMe3)(2)(THF) (3). All these complexes were applied to the copolymerization of cyclohexene oxide (CHO) and carbon dioxide as single-component catalysts.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A series of new rare-earth metal bis(alkyl) complexes [L(1-3)Ln(CH2SiMe3)(2)(THF)(n)] (L-1 = MeC4H2SCH2NC6H4(Ph)(2)P=NC6H2Me3-2,4,6: Ln = Sc, n = 1 (1a); Ln = Lu, n = 1 (1b); L-2 = MeC4H2SCH2NC6H4(Ph)(2)P=NC6H3Et2-2,6: Ln = Sc, n = 1 (2a); Ln = Lu, n = 1 (2b); Ln = Y, n = 1 (2c); L-3 = MeC4H2SCH2NC6H4(Ph)(2)P=(NC6H3Pr2)-Pr-i-2,6: Ln = Sc, n = 0 (3a)) and (LSc)-Sc-4(CH2SiMe3)(2()THF) (4a) (L-4 = C6H5CH2NC6H4(Ph)(2)P=NC6H3Et2-2,6) have been prepared by reaction of rare-earth metal tris(alkyl)s with the corresponding HL1-4 ligands via alkane elimination.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Reaction of 7-{(N-2,6-R)iminomethyl)}lindole (HL1, R = dimethylphenyl; HL2, R = diisopropylphenyl) and rare-earth metal tris(alkyl)s, Ln(CH2SiMe3)(3)(THF)(2), generated new rare-earth metal bis(alkyl) complexes LLn(CH2SiMe3)(2)(THF) [L = L-1: Ln = Lu. (1a), Sc (1b); L = L-2 : Ln = Lu (3a), Se (3b)] and mono(alkyl) complexes L-2 Lu-2(CH2SiMe3) (4a). Treatment of alkyl complexes 1a and 4a with N,N'-diisopropylcarbodiimide afforded the corresponding amidinates (LLu)-Lu-1{iPr(2)NC(CH2SiMe3) NiPr2}(2) (2a) and L-2 Lu-2{iPr(2)NC(CH2SiMe3)NiPr2} (5a), respectively.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fluorenyl modified N-heterocyclic carbene ligated rare earth metal bis(alkyl) complexes, (Flu-NHC)Ln(CH2SiMe3)2 (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (1a); Ln = Y (1b); Ln = Ho (1c); Ln = Lit (1d)), were synthesized and fully characterized by NMR and X-ray diffraction analyses. Complexes Ib-d with the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)4] exhibited high activity, medium syndio-but remarkably high 3,4-regio-selectivity, and the unprecedented livingness for the polymerization of isoprene. Such distinguished catalytic performances could be maintained under various monomer-to-initiator ratios (500-5000) and broad polymerization temperatures (25-80 degrees C).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Four cyclometalated Pt(II) complexes, i.e., [(L-2)PtCl] (1b), [(L-3)PtCl] (1c), [(L-2)PtC CC6H5] (2b) and [(L-3)PtC CC6H5] (2c) (HL2 = 4-[p-(N-butyl-N-phenyl)anilino]-6-phenyl-2,2'-bipyridine and HL3 = 4-[p(-N,N'-dibutyl-N'-phenyl)phenylene-diamino]-phenyl-6-phenyl-2,2'-bipyridine), have been synthesized and verified by H-1 NMR, C-13 NMR and X-ray crystallography. Unlike previously reported complexes [(L-1)PtCl] (1a) and [(L-1)PtC CC6H5] (2a) (HL1 = 4,6-diphenyl-2,2'-bipyridine), intense and continuous absorption bands in the region of 300-500 nm with strong metal-to-ligand charge transfer ((MLCT)-M-1) (d pi(Pt) -> pi*(L)) transitions (epsilon similar to 2 x 10(4) dm(3) mol (1) cm (1)) at 449-467 nm were observed in the UV-Vis absorption spectra of complexes 1b, 1c, 2b and 2c.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Stoichiometric reactions between mesityl azide (MesN(3), Mes = 2,4,6-C6H2Me3) and amino-phosphine ligated rare-earth metal alkyl, LLn(CH2SiMe3) (2)(THF) (L = (2,6-C6H3Me2)NCH2C6H4P(C6H5)(2); Ln = Lu (1a), Sc (1b)), amide, LLu(NH(2,6-(C6H3Pr2)-Pr-i))(2)(THF) (2) and acetylide at room temperature gave the amino-phosphazide ligated rare-earth metal bis(triazenyl) complexes, [L(MesN(3))]Ln[(MesN(3))-(CH2SiMe3)](2) (Ln = Lu (3a); Sc (3b)), bis(amido) complex [L(MesN3)] Lu[NH(2,6-C6H3 Pr-i(2))](2) (4), and bis(alkynyl) complex (5) (L(MesN(3))Lu (C CPh)(2))(2), respectively. The triazenyl group in 3 coordinates to the metal ion in a rare eta(2)-mode via N-beta and N-gamma atoms, generating a triangular metallocycle. The amino-phosphazide ligand, L(MesN(3)), in 3, 4 and 5 chelates to the metal ion in a eta(3)-mode via N-alpha and N-gamma atoms. In the presence of excess phenylacetylene, complex 3a isomerized to 3', where the triazenyl group coordinates to the metal ion in a eta(3) mode via Na and Ng atoms.