首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
烯基取代环戊二烯基钌配合物的合成及晶体结构   总被引:1,自引:0,他引:1  
金军挺  黄吉玲  钱延龙 《化学学报》1999,57(9):1043-1046
本文通过环戊二烯基钠(茂钠)与溴丙烯反应制得单取代的环戊二烯,茂钠与氯丙烯得到双取代的环戊二烯。利用这两个配体合成了烯基取代的环戊二烯基(双三苯膦)氯化钌(1,2)并对化合物(2)进行了晶体结构分析。  相似文献   

2.
The water‐soluble ruthenium(II) complexes [Cp′RuX(PTA)2]Y and [CpRuCl(PPh3)(mPTA)]OTf (Cp′ = Cp, Cp*, X = Cl and Y = nil; or X = MeCN and Y = PF6; PTA = 1,3,5‐triaza‐7‐phosphaadamantane; mPTA = 1‐methyl‐1,3,5‐triaza‐7‐phosphaadamantane) were used as catalyst precursors for the hydrogenation of CO2 and bicarbonate in aqueous solutions, in the absence of amines or other additives, under relatively mild conditions (100 bar H2, 30–80 °C), with moderate activities. Kinetic studies showed that the hydrogenation of HCO3? proceeds without an induction period, and that the rate strongly depends on the pH of the reaction medium. High‐pressure multinuclear NMR spectroscopy revealed that the ruthenium(II) chloride precursors are quantitatively converted into the corresponding hydrides under H2 pressure. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

3.
Inventing new wheels: reaction of [M(3)(CO)(12) ] (M=Ru, Os) with 4-RC(6)H(4)SH afforded [{M(S-4-RC(6)H(4))(2)(CO)(2)}(8)] (R=H; I) or [{M(S-4-RC(6)H(4))(2)(CO)(2)}(6)] (R=Me, iPr; II; see scheme), all of which have been structurally characterized. The octamers I are unique metal molecular wheels featuring skew-edge-shared octahedra with a central planar M(8) octagon. [{Ru(S-4-iPrC(6)H(4))(2)(CO)(2)}(6)] selectively binds a Cu(+) or Ag(+) ion to form [M'{Ru(S(4-iPr-C(6)H(4)))(2)(CO)(2)}(6)](+) (III).  相似文献   

4.
Novel arene-ruthenium [2+2] metalla-rectangles 4 and 5 have been synthesized by self-assembly using dipyridyl amide ligand 3 and arene-ruthenium acceptors (arene: benzoquinone (1), naphthacenedione (2)) and characterized by NMR spectroscopy and ESI-MS. The solid-state structure of 5 was determined by X-ray diffraction and shows encapsulated diethyl ether molecule in the rectangular cavity of 5. The luminescent 5 was further used for anion sensing with the amidic linkage serving as a hydrogen-bond donor site for anions and the ruthenium moiety serving as a signaling unit. A UV/Vis titration study demonstrated that although 5 interacts very weakly with common monoanions as well as with flexible dicarboxylate anions such as malonate and succinate, it displays significant binding affinity (K>10(3) in MeOH) for rigid multi-carboxylate anions such as oxalate, citrate, and tartrate, exhibiting a 1:1 stoichiometry. It has been suggested that 1:1 bidentate hydrogen bonding assisted by appropriate geometrical complementarity is mainly responsible for the increased affinity of 5 towards such anions. A fluorescence titration study revealed a large fluorescence enhancement of 5 upon binding to multi-carboxylate anions, which can be attributed to the blocking of the photoinduced electron-transfer process from the arene-Ru moiety to the amidic donor in 5 as a result of hydrogen bonding between the donor and the anion.  相似文献   

5.
Unsymmetrical substituted bidentate benzimidazol-2-ylpyridine ligands L2 and L3 react with [Ru(dmso)(4)Cl(2)] in ethanol to give statistical 1:3 mixtures of fac-[Ru(Li)(3)](2+) and mer-[Ru(Li)(3)](2+) (i=2, 3; DeltaGtheta(isomerisation)=-2.7 kJ mol(-1)). In more polar solvents (acetonitrile, methanol), the free energy of the facial<=>meridional isomerisation process favours mer-[Ru(Li)(3)](2+), which is the only isomer observed in solution at the equilibrium (DeltaGtheta(isomerisation)< or = -11.4 kJ mol(-1)). Since the latter process takes several days for [Ru(L2)(3)](2+), fac-[Ru(L2)(3)](2+) and mer-[Ru(L2)(3)](2+) have been separated by chromatography, but the 28-fold increase in velocity observed for [Ru(L3)(3)](2+) provides only mer-[Ru(L3)3](ClO(4))2 after chromatography (RuC(60)H(51)N(9)O(8)Cl(2), monoclinic, P2(1)/n, Z=4). The facial isomer can be stabilised when an appended tridentate binding unit, connected at the 5-position of the benzimidazol-2-ylpyridine unit in ligand L1, interacts with nine-coordinate lanthanides(III). The free energy of the facial<=>meridional isomerisation is reversed (DeltaGtheta(isomerisation)> or =11.4 kJ mol(-1)), and the Ru--N bonds are labile enough to allow the quantitative thermodynamic self-assembly of HHH-[RuLu(L1)(3)]5+ within hours ([RuLu(L1)3](CF(3)SO(3))(4.5)Cl(0.5)(CH(3)OH)(2.5): RuLuC(106)H(109)Cl(0.5)N(21)O(19)S(4.5)F(13.5), triclinic, P(-)1, Z=2). Electrochemical and photophysical studies show that the benzimidazol-2-ylpyridine units in L1-L3 display similar pi-acceptor properties to, but stronger pi-donor properties than, those found in 2,2'-bipyridine. This shifts the intraligand pi-->pi* and the MLCT transitions toward lower energies in the pseudo-octahedral [Ru(Li)(3)](2+) (i=2, 3) chromophores. The concomitant short lifetime of the (3)MLCT excited state points to efficient, thermally activated quenching via low-energy Ru-centred d-d states, a limitation which is partially overcome by mechanical coupling in HHH-[RuLu(L1)(3)]5+.  相似文献   

6.
7.
8.
Penta(ammine)ruthenium benzotriazole complexes [RuII/III(NH3)5bta]+/2+ and [RuII/III(NH3)5btaH]2+/3+ (bta and btaH are the deprotonated and neutral form of the triazole ligand, respectively) can exhibit two linkage isomers κN1 and κN2. This system was investigated by density functional theory natural bond orbitals analysis and Su-Li energy decomposition analysis. Steric, electrostatic, exchange, repulsion, polarization, and dispersion energy components of the total metal–ligand interaction were quantitatively evaluated, and revealed that the overall metal-triazole ligand is comprised of donor–acceptor interactions like σ-donation and π-back-donation, which favors a specific isomer depending on the oxidation state of the ruthenium and the charge of the ligand. Further, activation energies (ΔG) for linkage isomerization reactions were calculated. Results were correlated with experimental chemical–electrochemical data and two plausible mechanisms are discussed. © 2019 Wiley Periodicals, Inc.  相似文献   

9.
Non-metathesis reactions of ruthenium carbene catalysts, such as olefin isomerization, hydrogenation, radical reaction, activation of silane, cyclopropanation, epimerization cocyclopropane, [3 + 2] cycloaddition, and cycloisomerization, are summarized. The utility of these reactions was demonstrated by the synthesis of indole using olefin isomerization and subsequent ring-closing metathesis, the synthesis of indoline using cycloisomerization, and the synthesis of the putative structure of fistulosin using cycloisomerization as a key step.  相似文献   

10.
Calf thymus DNA (ct‐DNA) films were immobilized onto patterned silicon wafers through electrostatic self‐assembly technology and interacted with a novel dinuclear ruthenium (II) complex, [(bpy)2Ru(H2bpi)Ru(bpy)2](ClO4)4, which were demonstrated by using a confocal optical microscope. The morphology of the DNA film was measured by atomic force microscopy and the results show that the DNA strands have been folded into coiled conformations and aggregated into circles with diameters between 18 and 55 nm. The interaction process was also monitored by UV‐visible and fluorescence spectra and investigated by X‐ray photoelectron spectra. The results show that the Ru (II) complex interacts with ct‐DNA by the intercalative mode as it behaves in aqueous solutions. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

11.
12.
The mechanism of the trans to cis isomerization in Ru complexes with a chelating alkylidene group has been investigated by using a combined theoretical and experimental approach. Static DFT calculations suggest that a concerted single‐step mechanism is slightly favored over a multistep mechanism, which would require dissociation of one of the ligands from the Ru center. This hypothesis is supported by analysis of the experimental kinetics of isomerization, as followed by 1H NMR spectroscopy. DFT molecular dynamics simulations revealed that the variation of geometrical parameters around the Ru center in the concerted mechanism is highly uncorrelated; the mechanism actually begins with the transformation of the square‐pyramidal trans isomer, with the Ru?CHR bond in the apical position, into a transition state that resembles a metastable square pyramidal complex with a Cl atom in the apical position. This high‐energy structure collapses into the cis isomer. Then, the influence of the N‐heterocyclic carbene ligand, the halogen, and the chelating alkylidene group on the relative stability of the cis and trans isomers, as well as on the energy barrier separating them, was investigated with static calculations. Finally, we investigated the interconversion between cis and trans isomers of the species involved in the catalytic cycle of olefin metathesis; we characterized an unprecedented square‐pyramidal metallacycle with the N‐heterocyclic carbene ligand in the apical position. Our analysis, which is relevant to the exchange of equatorial ligands in other square pyramidal complexes, presents evidence for a remarkable flexibility well beyond the simple cistrans isomerization of these Ru complexes.  相似文献   

13.
14.
15.
[2]Rotaxanes based on the 1,2-bis(pyridinium)ethane subset[24]crown-8 ether motif were prepared that contain a terminal terpyridine group for coordination to a transition-metal ion. These rotaxane ligands were utilized in the preparation of a series of heteroleptic [Ru(terpy)(terpy-rotaxane)]2+ complexes. The compounds were characterized by 1D and 2D 1H NMR spectroscopy, X-ray crystallography, and high-resolution electrospray ionization mass spectrometry. The effect of using a rotaxane as a ligand was probed by UV/Vis/NIR absorption and emission spectroscopy of the Ru(II) complexes. In contrast with the parent [Ru(terpy)(2)]2+ complex, at room temperature the examined complexes exhibit a luminescence band in the near infrared region and a relatively long lived triplet metal-to-ligand charge-transfer (3MLCT) excited state, owing to the presence of strong-electron-acceptor pyridinium substituents on one of the two terpy ligands. Visible-light excitation of the Ru-based chromophore in acetonitrile at room temperature causes an electron transfer to the covalently linked 4,4'-bipyridinium unit and the quenching of the MLCT luminescence. The 3MLCT excited state, however, is not quenched at all in rigid matrix at 77 K. The rotaxane structure was found to affect the absorption and luminescence properties of the complexes. In particular, when a crown ether surrounds the cationic axle, the photoinduced electron-transfer process is slowed down by a factor from 2 to 3. Such features, together with the synthetic and structural advantages offered by [Ru(terpy)2]2+-type complexes compared to, for example, [Ru(bpy)3]2+-type compounds, render these rotaxane-metal complexes promising candidates for the construction of photochemical molecular devices with a wire-type structure.  相似文献   

16.
Recent developments have helped to extend the repertoire of mixed-valent ruthenium and osmium complexes beyond conventional systems. This extension has been achieved by using sophisticated ligands and by creating more variegated coordination patterns. The strategies employed include the use of multidentate ligands (which give rise to multinuclear and chelate complexes) and the use several redox active components (non-innocent ligands and oxidation-state ambivalence). The results offer enhanced chemical insight into metal-ligand electron-transfer situations and suggest that mixed-valent materials may eventually be exploited in molecular electronics and molecular computing.  相似文献   

17.
The interactions of the tetracationic meso-tetrakis(N-methyl-4-pyridyl)porphyrin (H(2)TMPyP) and its metallo derivatives (MTMPyP) (where M=copper(II), zinc(II), and gold(III) with the octa-anionic form (at neutral pH) of 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis(hydroxycarbonylmethoxy)calix[4]arene (C(4)TsTc) lead to a series of complex species whose stoichiometry and porphyrin sequence can be easily tuned. Crystallographic, spectroscopic, and diffusion NMR studies converge towards a common picture in which a central 1:4 porphyrin/calixarene unit serves as a template for the formation of more complex species. These species arise by successive, stepwise addition of single porphyrin molecules above and below the plane of the 1:4 central core to ultimately give a 7:4 complex. Noticeably, the stoichiometry of the various complex species corresponds to the actual concentration ratio of porphyrins and calixarenes in solution allowing the stoichiometry of these species to be easily tuned. This behavior and the remarkable stability of these species allow homo-porphyrin and hetero-(metallo)porphyrin species to be formed with control of not only the stoichiometry but also the sequence of the porphyrin array. The flexibility and ease of this approach permit, in principle, the design and synthesis of porphyrin arrays for predetermined purposes. For example, we have shown that it is very easy to design and obtain mixed porphyrin species in which a foreseen photoinduced electron-transfer is indeed observed.  相似文献   

18.
Two new dimethylvinyl carbene complexes, RuCl2(SIMes)(PPh3)CHCHC(CH3)2 and RuCl2(SIMes)(3BP)2CHCHC(CH3)2, were synthesized from RuCl2(PCp3)2CHCHC(CH3)2. Complex RuCl2(SIMes)(3BP)2CHCHC(CH3)2 does not suffer from the problem of incomplete initiation that has been observed for the other dimethylvinyl carbene complexes, as witnessed by complete and rapid reaction with ethyl vinyl ether. Acyclic diene metathesis (ADMET) polymerization of 1,9‐decadiene with these complexes was found to give polymers with chemical and thermal properties similar to those obtained with Schrock's molybdenum catalyst. These complexes are also catalysts for ring‐opening metathesis polymerization. The parent complex RuCl2(SIMes)(PCp3)CHCHC(CH3)2 was found to give polyoctenamer with high initial heats of fusion, suggesting a dependence of the “as formed” crystallinity of the polymer on the rate of the ROMP reaction. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6134–6145, 2005  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号