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1.
The novel organometallic sandwich complexes [(eta(6)-p-cymene)Ru(eta(6)-aspartame)](OTf)(2) (1) (OTf = trifluoromethanesulfonate) and [(eta(6)-p-cymene)Os(eta(6)-aspartame)](OTf)(2) (2) incorporating the artificial sweetener aspartame have been synthesised and characterised. A number of properties of aspartame were found to be altered on binding to either metal. The pK (a) values of both the carboxyl and the amino groups of aspartame are lowered by between 0.35 and 0.57 pH units, causing partial deprotonation of the amino group at pH 7.4 (physiological pH). The rate of degradation of aspartame to 3,6-dioxo-5-phenylmethylpiperazine acetic acid (diketopiperazine) increased over threefold from 0.12 to 0.36 h(-1) for 1, and to 0.43 h(-1) for 2. Furthermore, the reduction potential of the ligand shifted from -1.133 to -0.619 V for 2. For the ruthenium complex 1 the process occurred in two steps, the first (at -0.38 V) within a biologically accessible range. This facilitates reactions with biological reductants such as ascorbate. Binding to and activation of the sweet taste receptor was not observed for these metal complexes up to concentrations of 1 mM. The factors which affect the ability of metal-bound aspartame to interact with the receptor site are discussed.  相似文献   

2.
Pyrazole-3,5-dicarboxylate-bridged dinuclear ruthenium(II) and osmium(II) complexes of 2,2-bipyridine of composition [(bpy)2Ru(pzdc)Ru(bpy)2](ClO4) · H2O (1) and [(bpy)2Os(pzdc)Os(bpy)2](ClO4) · H2O (2) have been obtained in high yield and have been separated to their homochiral (ΛΛ/ΔΔ) rac (1a, 2a) and heterochiral (ΛΔ/ΔΛ) meso (1b, 2b) diastereoisomers. The distinctive structural features of these diastereoisomers have been characterized by 1-D and 2-D 1H NMR spectroscopy. The X-ray crystal structure of rac-[(bpy)2Os(pzdc)Os(bpy)2](ClO4) · H2O (2a) has been determined. The electrochemical and electronic spectral studies have established that there remain difference in properties and hence difference in intermetallic communication between the diastereoisomeric forms in each case.  相似文献   

3.
Three ruthenium polypyridyl compounds of structural formula [Ru(apy)(tpy)Ln](ClO4)(2−n) (apy = 2,2′-azobispyridine; tpy = 2,2′:6′,2″-terpyridine; L = Cl, H2O, CH3CN) (1a-c) were synthesized and crystallized. These complexes were fully characterized by means of 1D and 2D 1H NMR spectroscopy, as well as mass spectrometry and elemental analysis. Although in theory two isomers are possible, i.e. the one in which the central N atom in tpy is trans to the azo N in apy and the one in which the former is trans to the pyridine N in apy, in all cases only the latter was observed. The molecular structures of the compounds were elucidated by single-crystal X-ray diffraction.  相似文献   

4.
Ruthenium complexes [Ru(mpy)2(DMSO)2] (1) and [Ru(mbtz)2(DMSO)2] (2) containing 2-mercaptopyridine (mpy) and 2-mercaptobenzothiazole (mbtz) have been synthesized. Reactivity of 1 have been examined with 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen), EPh3 (E = P, As) and 1,2-bis(diphenylphosphino)-methane (dppm). It reacted with bipy or phen in DMF to afford [Ru(mpy)2(bipy)] (3) and [Ru(mpy)2(phen)] (4) while, its reaction with EPh3 or dppm in common organic solvents failed to afford products containing EPh3 or dppm. Complexes under investigation have been characterized by elemental analyses, spectral, electrochemical studies and structures of 1-4 have been determined crystallographically. Density functional theory calculations have been performed on 1-4 and the model complex [Ru(mpy)(PMe3)2] (5) using exchange correlation functionals BP86. Optimized bond length and angles are in good agreement with the structural data. The Ru-N and Ru-S bond distances in [Ru(mpy)2]-moiety of 1 are relatively shorter than 5, indicating higher stability of 1 in comparison to 5. The WBI values of Ru-N1, Ru-N2, Ru-S1 and Ru-S2 bonds indicate Ru-mpy bonding trend as 3 > 4 > 1 > 5. There is an overall charge flow in the direction L → [Ru(mpy)2] (L = DMSO, bipy, phen and PMe3). Due to greater ionic character and Pauli repulsive interactions for Ru-PMe3 bond in comparison to Ru-DMSO, the DMSO ligands in 1 may not be substituted by phosphine ligands experimentally.  相似文献   

5.
The dinuclear arene ruthenium complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}]2 (1) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}]2 (2) have been obtained by dehydrogenation of the corresponding cyclohexadiene derivative with ruthenium chloride hydrate. The single-crystal X-ray structure analysis of 2 shows the arene ligands to be involved in slipped-parallel π-π stacking interactions with neighbouring molecules, thus forming infinite chains along the b-axis. The dinuclear complexes 1 and 2 react with two equivalents of triphenylphosphine (PPh3) to give in excellent yield the corresponding mononuclear phosphine complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}(PPh3)] (3) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}(PPh3)] (4), respectively. The single-crystal X-ray structure analysis of 4 reveals the formation of a dimer through two C-H?Cl interactions in the solid state.  相似文献   

6.
Ruthenium(II) arene anticancer complexes [(η 6-arene)Ru(en)Cl]PF6 (arene is hexamethylbenzene, p-cymene, indan; en is ethylenediamine) can catalyse regioselective reduction of NAD+ by formate in water to form 1,4-NADH, at pD 7.2, 37 °C, and in the presence of air. The catalytic activity is markedly dependent on the arene, with the hexamethylbenzene (hmb) complex showing the highest activity. For [(η 6-hmb)Ru(en)Cl]PF6, the rate of reaction is independent of NAD+ concentration and shows saturation kinetics with respect to formate concentration. A K m value of 58 mM and a turnover frequency at saturation of 1.46 h−1 were observed. Removal of chloride and performing the reaction under argon led to higher reaction rates. Lung cancer cells (A549) were found to be remarkably tolerant to formate even at millimolar concentrations. The possibility of using ruthenium arene complexes coadministered with formate as catalytic drugs is discussed.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.  相似文献   

7.
The reactions of zinc and cadmium salts with 2,2′-biimidazole (H2biim) yielded a series of compounds in which the ligand is coordinated in the chelating bidentate mode. ZnCl2 and [Ag(H2biim)](NO3) in methanol in a 2:1 proportion produced Zn(H2biim)Cl2, in which the metal has a distorted tetrahedral coordination. A 1:2 ratio led to [Zn(H2biim)2(CH3OH)2](NO3)2, containing an octahedrally coordinated Zn(II) center with the O-bonded methanol ligands occupying trans positions. The corresponding [Cd(H2biim)2(CH3OH)2](NO3)2 compound was obtained from CdCl2. By starting with Cd(NO3)2 and Cd(ClO4)2 in aqueous media, the related octahedral bis-chelate compounds [Cd(H2biim)2(NO3)(H2O)](NO3) and Cd(H2biim)2(ClO4)2, respectively, were isolated, the apical positions being filled by perchlorate oxygens in the latter case. With Cd(BF4)2, the glass container participated in the reaction and a tris-chelate complex [Cd(H2biim)3]2(SiF6)(BF4)2 · 6EtOH was isolated. The [Cd(H2biim)3]2+ and ions define an extended hydrogen-bonded network, in which ions surrounded by disordered ethanol molecules occupy large cavities. The two free N-H groups provide H2biim with a unique ability to form hydrogen bonds and their interactions with counter anions or other acceptors play a determining role in controlling molecular packing. The IR spectra of all compounds are discussed.  相似文献   

8.
Reactions between Hdpa (2,2′-dipyridylamine) and either RuCl3 · xH2O and Ru2(OAc)4Cl produce mono-, di-, and tri-ruthenium complexes under various conditions. The ligand Hdpa and RuCl3 · xH2O react in boiling DMF to form the ionic species [Ru(Hdpa)2Cl2]Cl (1). Reaction of Ru2(OAc)4Cl with molten Hdpa leads to scission of the Ru-Ru bond and formation of the vertex-sharing bioctahedral complex Ru2(dpa)3(OAc)0.64Cl1.36 (2). A mixture of both of these species results from the reaction of Ru2(OAc)4Cl with Hdpa and LiCl in refluxing o-dichlorobenzene/EtOH mixtures. This mixture of compounds reacts further with KOBut and n-butanol in refluxing naphthalene to give low yields of the extended metal atom chain (EMAC) complex Ru3(dpa)4Cl2 (I).  相似文献   

9.
The reaction of [C5H4(CH2)nX]Tl (1: n = 2, X = NMe2, OMe, CN; n = 3, X = NMe2) with [(η6-C6H6)RuCl(μ-Cl)]2, 2, afforded the sandwich compounds [{η5-C5H4(CH2)nX}Ru(η6-C6H6)]PF6, 3, and [η5-C5H4(CH2)nX]2Ru, 4. Photolytic cleavage of 3 in acetonitrile afforded the tethered products [{η5N-C5H4(CH2)nX}Ru(CH3CN)2]PF6, 5.  相似文献   

10.
A complete photophysical study has been carried out on an octahedral ruthenium(II) complex, incorporating two 4′-phenylethynyl-2,2′:6′,2″-terpyridine ligands. Weak emission is observed from the complex in fluid solution at room temperature, but both emission yield and lifetime increase as the temperature is lowered. Luminescence is confirmed to occur exclusively from the lowest energy triplet metal-to-ligand, charge-transfer (MLCT) state, though higher-lying MLCT and metal-centered states are required to adequately model the non-radiative decay kinetics. A comparison of parameters associated with deactivation of the complex and its counterpart, where only one terpy ligand incorporates the phenylethynyl unit, indicates that only the electron-vibrational coupling element is affected. It is also revealed that the extent of electron delocalisation at the triplet level does not critically depend on the number of 4-phenylethynyl-2,2′:6′,2″-terpyridine ligands in the complex.  相似文献   

11.
New ruthenium(II) complexes with cyanamide ligands, cis-[Ru(bpy)2(Ipcyd)2] (1) and [Ru(bpy)2(OHpcyd)2] (2) (bpy = 2,2′-bipyridine, Ipcyd = 4-iodophenylcyanamide anion, OHpcyd = 4-(3-hydroxy-3-methylbut-1-ynil)phenylcyanamide), have been prepared and characterized by UV-Vis, IR and 1H NMR spectroscopies as well as electrochemical technique (CV). The complex cis-[Ru(bpy)2(Ipcyd)2] (1) crystallized with empirical formula of C34H24I2N8Ru in a monoclinic crystal system and space group of P21/c with a = 11.769(7) Å, b = 24.188(12) Å, c = 11.623(2) Å, β = 91.63(3)°, V = 3308(3) Å3 and Z = 4.  相似文献   

12.
We report the synthesis of a new ligand, 4,4′-bis(3,5-dimethoxyphenyl)-6,6′-dimethyl-2,2′-bipyridine, optimised for binding to copper(I) and with pendant functionality that can eventually be developed into metallodendritic structures. The synthesis and photophysical properties of complexes with copper(I) and ruthenium(II) are reported. The solid state structure of the complex [Cu(1)2][PF6] · MeCN (1 = 4,4′-bis(3,5-dimethoxyphenyl)-6,6′-dimethyl-2,2′-bipyridine) is also described.  相似文献   

13.
Substitution reaction of chloro η6-arene ruthenium N∩O-base complexes [(η6-arene)Ru(N∩O)Cl] [N∩O = pyrazine-2-carboxylic acid (pca-H), 8-hydroxyquinoline (hq-H); arene = p-iPrC6H4Me, N∩O = hq (1); arene = C6Me6, N∩O = hq (2)] with NaN3 yield the neutral arene ruthenium azido complexes of the general formula [(η6-arene)Ru(N∩O)N3] [N∩O = pca, arene = p-iPrC6H4Me (3), arene = C6Me6 (4); N∩O = hq, arene = p-iPrC6H4Me (5), arene = C6Me6 (6)]. These complexes undergo [3 + 2] dipolar cycloaddition reaction with activated alkynes dimethyl and diethyl acetylenedicarboxylates to yield the arene triazole complexes [(η6-arene)Ru(N∩O){N3C2(CO2R)2}] [N∩O = pca, R = Me, arene = p-iPrC6H4Me (7), C6Me6 (8); R = Et, arene = p-iPrC6H4Me (9), C6Me6 (10); N∩O = hq, R = Me, arene = p-iPrC6H4Me (11) C6Me6 (12); R = Et, arene = p-iPrC6H4Me (13), C6Me6 (14)]. On the bases of proton NMR study, in the above triazole complexes N(2) isomers are assigned with dimethylacetylenedicarboxylate whereas N(1) isomers with diethylacetylenedicarboxylate. All complexes have been characterized by IR and NMR spectroscopy as well as by elemental analysis. The molecular structures of the azido complexes [(η6-p-iPrC6H4Me)Ru(pca)N3] (3), [(η6-p-iPrC6H4Me)Ru(hq)N3] (5) and [(η6-C6Me6)Ru(hq)N3] (6) have been established by single crystal X-ray diffraction studies.  相似文献   

14.
Two new mononuclear Mn(II) complexes, Mn(dmbpy)2(OCN)2 (1) and Mn(dmbpy)2(dca)2 (2) (dmbpy = 4,4′-dimethyl-2,2′-bipyridine, dca = dicyanamide), have been synthesized and characterized by IR, elemental analysis, and single crystal X-ray analysis. Both complexes have similar molecular structures. The coordination sphere of the Mn(II) ion in 1 or 2 is a seriously distorted octahedron formed by two dmbpy ligands and two OCN or dca anions in cis positions. For both complexes, the most striking feature is that the mononuclear molecules are linked together by plentiful weak C-H?N hydrogen bonds into a compact 3D supramolecular structure. DNA cleavage studies show that the complexes can promote plasmid DNA cleavage in the presence of H2O2 under physiological conditions, and their cleavage activities are obviously both pH value and complex concentration-dependent. The cleavage mechanism between the complexes and plasmid DNA is likely to involve hydroxyl radicals as reactive oxygen species.  相似文献   

15.
The new complex, [RuII(bpy)2(4-HCOO-4′-pyCH2 NHCO-bpy)](PF6)2 · 3H2O (1), where 4-HCOO-4′-pyCH2NHCO-bpy is 4-(carboxylic acid)-4′-pyrid-2-ylmethylamido-2,2′-bipyridine, has been synthesised from [Ru(bpy)2(H2dcbpy)](PF6)2 (H2dcbpy is 4,4′-(dicarboxylic acid)-2,2′-bipyridine) and characterised by elemental analysis and spectroscopic methods. An X-ray crystal structure determination of the trihydrate of the [Ru(bpy)2(H2dcbpy)](PF6)2 precursor is reported, since it represented a different solvate to an existing structure. The structure shows a distorted octahedral arrangement of the ligands around the ruthenium(II) centre and is consistent with the carboxyl groups being protonated. A comparative study of the electrochemical and photophysical properties of [RuII(bpy)2(4-HCOO-4′-pyCH2NHCO-bpy)]2+ (1), [Ru(bpy)2(H2dcbpy)]2+ (2), [Ru(bpy)3]2+ (3), [Ru(bpy)2Cl2] (4) and [Ru(bpy)2Cl2]+ (5) was then undertaken to determine their variation upon changing the ligands occupying two of the six ruthenium(II) coordination sites. The ruthenium(II) complexes exhibit intense ligand centred (LC) transition bands in the UV region, and broad MLCT bands in the visible region. The ruthenium(III) complex, 5, displayed overlapping LC bands in the UV region and a LMCT band in the visible. 1, 2 and 3 were found, via cyclic voltammetry at a glassy carbon electrode, to exhibit very positive reversible formal potentials of 996, 992 and 893 mV (versus Fc/Fc+) respectively for the Ru(III)/Ru(II) half-cell reaction. As expected the reversible potential derived from oxidation of 4 (−77 mV (versus Fc/Fc+)) was in excellent agreement with that found via reduction of 5 (−84 mV (versus Fc/Fc+)). Spectroelectrochemical experiments in an optically transparent thin-layer electrochemical cell configuration allowed UV-Vis spectra of the Ru(III) redox state to be obtained for 1, 2, 3 and 4 and also confirmed that 5 was the product of oxidative bulk electrolysis of 4. These spectrochemical measurements also confirmed that the oxidation of all Ru(II) complexes and reduction of the corresponding Ru(III) complex are fully reversible in both the chemical and electrochemical senses.  相似文献   

16.
A series of cationic, half-sandwich ruthenium complexes with the general formula [(η6-p-cymene)RuCl(MeSC6H42-NCHAr)][PF6] (3a-h), have been prepared from the reaction of [(η6-p-cymene)RuCl2]2 with various N,S-donor Schiff base ligands derived from 2-(methylthio)aniline and several substituted benzaldehydes. The related aniline complex [(η6-p-cymene)RuCl(MeS-C6H4-2-NH2)][PF6] (4) was synthesized from 2-(methylthio)aniline. All of the ruthenium complexes were characterized by IR, 1H NMR, and UV/Vis spectroscopies. The molecular structure of complex 4 was determined by X-ray crystallography.  相似文献   

17.
Tris-chelate 5-hydroxymethyl-2,2′-bipyridine complexes of ruthenium (II) and the structurally related benzo- and naphthoesters have been isolated. The mer-isomer of the alcohol functionalised complex has been isolated by selective precipitation from methylene chloride and was subsequently functionalised to the benzoester with retention of the geometrical isomerism. The fac- and mer-isomeric forms of the ester complexes were separated using preparative plate silica chromatography and characterised by 1H NMR spectroscopy. X-ray structural analysis of the fac-isomer of both the ester complexes confirmed the product assignment. The photophysical properties of the three isomers were investigated, indicating very similar absorption spectra to [Ru(bipy)3]2+. The emission wavelength was comparable in each case, with the aromatic ester complexes giving a much longer lifetime and higher quantum yields  相似文献   

18.
A series of magnesium complexes of general formula [Mg(Tpx)2] (Tpx = Tp, Tp, TpCl, pzTp) and [Mg(Tpx)X] (X = Cl, Tpx = TptBu or pz0Tpp-Tol; X = acetate, Tpx = TptBu) were synthesised from magnesium chloride or acetate and M(Tpx) (M = K, Na or Tl) in dichloromethane or alcoholic solution. These compounds are air-stable solids, sparingly soluble in most organic solvents; they have been characterized by elemental analysis, IR, 1H and 13C NMR spectra and, in selected cases, also by conductivity and molecular weight measurements. Single crystal X-ray diffraction studies of [Mg(Tp)2], [Mg(Tp*)2] and [Mg(Tp*Cl)2] show unsolvated neutral bis(tripod ligand)magnesium(II) molecules with six-coordinate magnesium atoms (〈Mg-N〉 2.167(6), 2.19(2), 2.205(4) Å).  相似文献   

19.
Ruthenium complexes with a terpyridine-analogous ligand, 2,6-bis(2-naphthyridyl)pyridine (bnp), have been synthesized and their chemical and electrochemical properties investigated. The structures of [Ru(bnp)(tpy)](PF6)2 (1) and [Ru(bnp)2](PF6)2 (2) were determined by the X-ray structure analysis. The bnp localized redox potentials of 1 and 2 showed significant positive shift by 260-290 mV relative to the analogous Ru-terpyridine complexes.  相似文献   

20.
Four ligands whose general formula is R-terpy with terpy = 2,2′:6′,2″ terpyridine bearing at the 4′-position a substituent R = 2-furyl, 2-pyrrolyl, 2-thienyl and 5-2,2′bithienyl were synthesised. The absorption spectra and the electrochemical behaviour of the corresponding homoleptic Ru(II) complexes were investigated and compared to those of the parent complex [Ru(terpy)]2+. Due to the donor effect of the grafted heterocyclic groups, the absorption and emission maxima are red-shifted and the energy levels of the HOMO Π(t2g) metal orbitals are slightly higher. The incorporation of these heterocyclic moieties extends the electronic delocalisation over the corresponding ligands, leading to higher emission quantum yields. Cyclic voltammetric studies of pyrrolyl-, thienyl- and bithienyl-functionalised complexes show that an electroactive layer can be deposited on the electrode. Preliminary results point out that an electrodeposited film could be used as a photocathode in an aqueous electrolyte.  相似文献   

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