Synthesis, anticancer and antibacterial activity of some novel mononuclear Ru(II) complexes

In search of potential anticancer drug candidates in ruthenium complexes, a series of mononuclear ruthenium complexes of the type [Ru(phen)(2)(nmit)]Cl(2) (Ru1), [Ru(bpy)(2)(nmit)]Cl(2) (Ru2), [Ru(phen)(2)(icpl)]Cl(2) (Ru3), Ru(bpy)(2)(icpl)]Cl(2) (Ru4) (phen=1,10-phenanthroline; bpy=2,2'-bipyridine; nmit=N-methyl-isatin-3-thiosemicarbazone, icpl=isatin-3-(4-Cl-phenyl)thiosemicarbazone) and [Ru(phen)(2)(aze)]Cl(2) (Ru5), [Ru(bpy)(2)(aze)]Cl(2) (Ru6) (aze=acetazolamide) and [Ru(phen)(2)(R-tsc)](ClO(4))(2) (R=methyl (Ru7), ethyl (Ru8), cyclohexyl (Ru9), 4-Cl-phenyl (10), 4-Br-phenyl (Ru11), and 4-EtO-phenyl (Ru12), tsc=thiosemicarbazone) were prepared and characterized by elemental analysis, FTIR, (1)H-NMR and FAB-MS. Effect of these complexes on the growth of a transplantable murine tumor cell line (Ehrlich Ascites Carcinoma) and their antibacterial activity were studied. In cancer study the effect of hematological profile of the tumor hosts have also been studied. In the cancer study, the complexes Ru1-Ru4, Ru10 and Ru11 have remarkably decreased the tumor volume and viable ascitic cell count as indicated by trypan blue dye exclusion test (p<0.05). Treatment with the ruthenium complexes prolonged the lifespan of Ehrlich Ascites Carcinoma (EAC) bearing mice. Tumor inhibition by the ruthenium chelates was followed by improvements in hemoglobin, RBC and WBC values. All the complexes showed antibacterial activity, except Ru5 and Ru6. Thus, the results suggest that these ruthenium complexes have significant antitumor property and antibacterial activity. The results also reflect that the drug does not adversely affect the hematological profiles as compared to that of cisplatin on the host.     

Solid-state Ru-99 NMR spectroscopy: a useful tool for characterizing prototypal diamagnetic ruthenium compounds

The feasibility of (99)Ru NMR spectroscopy as a tool to characterize solid compounds is demonstrated. Results of the first solid-state (99)Ru NMR investigation of diamagnetic compounds are presented for Ru(NH(3))(6)Cl(2), K(4)Ru(CN)(6). xH(2)O (x = 0, 3), LaKRu(CN)(6), and Ru(3)(CO)(12). The sensitivity of the ruthenium magnetic shielding tensor to subtle changes in the local structure about the ruthenium nucleus is highlighted by comparing the (99)Ru isotropic chemical shift of Ru(NH(3))(6)Cl(2) in aqueous solutions and in the solid state. The narrow isotropic (99)Ru NMR peak observed for solid Ru(NH(3))(6)Cl(2) indicates that this compound is an ideal secondary reference sample for solid-state (99)Ru NMR studies. The isotropic (99)Ru chemical shift, (99)Ru nuclear quadrupolar coupling constant, C(Q), and quadrupolar asymmetry parameter of K(4)Ru(CN)(6). xH(2)O (x = 0, 3) are shown to be sensitive to x. For Ru(3)(CO)(12), the magnetic shielding tensors of each of the three nonequivalent Ru nuclei have spans of 1300-1400 ppm, and the (99)Ru C(Q) values are also similar, 1.36-1.85 MHz, and are surprisingly small given that (99)Ru has a moderate nuclear quadrupole moment. Information about the relative orientation of the Ru magnetic shielding and electric field gradient tensors has been determined for Ru(3)(CO)(12) from experimental (99)Ru NMR spectra as well as quantum chemical calculations.     

Synthesis and reactivity of {Ru(p-cymene)}2+ derivatives of [Nb6O19]8-: a rational approach towards fluxional organometallic derivatives of polyoxometalates

Three {Ru(p-cym)}(2+) (p-cym = p-cymene) derivatives of [Nb(6)O(19)](8-)-[Nb(6)O(19){Ru(p-cym)}](6-) (Nb(6)Ru(1)), trans-[Nb(6)O(19){Ru(p-cym)}(2)](4-) (t-Nb6Ru2), and [Nb(6)O(19){Ru(p-cym)}(4)] (Nb(6)Ru(4))--have been synthesized in water by reaction between [Ru(p-cym)Cl(2)](2) and the hexaniobate. In the solid state, Nb(6)Ru(1) and Nb(6)Ru(4) have been characterized by IR and EDX spectroscopies, whereas t-Nb(6)Ru(2) has been characterized by IR spectroscopy and single-crystal X-ray diffraction (crystal data for K(4)-trans-[Nb(6)O(19){Ru(p-cym)}(2)].14H(2)O (K(4)-t-Nb(6)Ru(2).14H(2)O). In solution, all compounds were characterized by (1)H NMR and ESI mass spectrometry analyses, and Nb(6)Ru(1) was also analyzed by (17)O NMR. These studies allowed a comparison of the differences in behaviour of the three complexes in water: Nb(6)Ru(1) is particularly stable, Nb(6)Ru(4) decomposes by loss of {Ru(p-cym)}(2+) fragments, and trans-[Nb(6)O(19){Ru(p-cym)}(2)](4-) isomerizes into cis-[Nb(6)O(19){Ru(p-cym)}(2)](4-). A rational mechanism for the isomerisation of t-Nb(6)Ru(2) is proposed on the basis of a kinetic study.     

CO在担载Ru催化剂上的吸脱附作用及其表面加氢反应

研究了担载于Al_2O_3和ZrO_2上的以Ru_3(CO)_(12)为前体的[Ru]和以RuCl_3为前体的Ru催化剂的TPR特性、CO吸脱附行为及其表面加H_2反应。担载于Al_2O_3上的[Ru]和Ru催化剂上部分物相较担载于ZrO_2上者难于还原。CO在氧化[Ru]催化剂上主要以Ru(CO)yO_2表面络合物形式存在,在还原[Ru]和Ru、以及氧化Ru催化剂上CO以吸附物种形式存在。在Ru离子上的CO比在Ru原子上者难于脱附。以ZrO_2为载体的[Ru]和Ru催化剂上的CO加H_2生成CH_4的性能显著优于以Al_2O_3为载体者,担载[Ru]催化剂上的CO加H_2性能略优于担载Ru催化剂。     

Coordination and Redox Chemistry of Substituted-Polypyridyl Complexes of Ruthenium

The complexes [Ru(tpy)(acac)(Cl)], [Ru(tpy)(acac)(H(2)O)](PF(6)) (tpy = 2,2',2"-terpyridine, acacH = 2,4 pentanedione) [Ru(tpy)(C(2)O(4))(H(2)O)] (C(2)O(4)(2)(-) = oxalato dianion), [Ru(tpy)(dppene)(Cl)](PF(6)) (dppene = cis-1,2-bis(diphenylphosphino)ethylene), [Ru(tpy)(dppene)(H(2)O)](PF(6))(2), [Ru(tpy)(C(2)O(4))(py)], [Ru(tpy)(acac)(py)](ClO(4)), [Ru(tpy)(acac)(NO(2))], [Ru(tpy)(acac)(NO)](PF(6))(2), and [Ru(tpy)(PSCS)Cl] (PSCS = 1-pyrrolidinedithiocarbamate anion) have been prepared and characterized by cyclic voltammetry and UV-visible and FTIR spectroscopy. [Ru(tpy)(acac)(NO(2))](+) is stable with respect to oxidation of coordinated NO(2)(-) on the cyclic voltammetric time scale. The nitrosyl [Ru(tpy)(acac)(NO)](2+) falls on an earlier correlation between nu(NO) (1914 cm(-)(1) in KBr) and E(1/2) for the first nitrosyl-based reduction 0.02 V vs SSCE. Oxalate ligand is lost from [Ru(II)(tpy)(C(2)O(4))(H(2)O)] to give [Ru(tpy)(H(2)O)(3)](2+). The Ru(III/II) and Ru(IV/III) couples of the aqua complexes are pH dependent. At pH 7.0, E(1/2) values are 0.43 V vs NHE for [Ru(III)(tpy)(acac)(OH)](+)/[Ru(II)(tpy)(acac)(H(2)O)](+), 0.80 V for [Ru(IV)(tpy)(acac)(O)](+)/[Ru(III)(tpy)(acac)(OH)](+), 0.16 V for [Ru(III)(tpy)(C(2)O(4))(OH)]/[Ru(II)(tpy)(C(2)O(4))(H(2)O)], and 0.45 V for [Ru(IV)(tpy)(C(2)O(4))(O)]/[Ru(III)(tpy)(C(2)O(4))(OH)]. Plots of E(1/2) vs pH define regions of stability for the various oxidation states and the pK(a) values of aqua and hydroxo forms. These measurements reveal that C(2)O(4)(2)(-) and acac(-) are electron donating to Ru(III) relative to bpy. Comparisons with redox potentials for 21 related polypyridyl couples reveal the influence of ligand changes on the potentials of the Ru(IV/III) and Ru(III/II) couples and the difference between them, DeltaE(1/2). The majority of the effect appears in the Ru(III/II) couple. ()A linear correlation exists between DeltaE(1/2) and the sum of a set of ligand parameters defined by Lever et al., SigmaE(i)(L(i)), for the series of complexes, but there is a dramatic change in slope at DeltaE(1/2) approximately -0.11 V and SigmaE(i)(L(i)) = 1.06 V. Extrapolation of the plot of DeltaE(1/2) vs SigmaE(i)(L(i)) suggests that there may be ligand environments in which Ru(III) is unstable with respect to disproportionation into Ru(IV) and Ru(II). This would make the two-electron Ru(IV)O/Ru(II)OH(2) couple more strongly oxidizing than the one-electron Ru(IV)O/Ru(III)OH couple.     

First example of mu(3)-sulfido bridged mixed-valent triruthenium complex triangle Ru(III)(2)Ru(II)(O,O-acetylacetonate)(3)(mu-O,O,gamma-C-acetylacetonate)(3)(mu(3)-S) (1) incorporating simultaneous O,O- and gamma-C-bonded bridging acetylacetonate units. Synthesis,crystal structure,and spectral and redox properties

The reaction of mononuclear ruthenium precursor [Ru(II)(acac)(2)(CH(3)CN)(2)] (acac = acetylacetonate) with the thiouracil ligand (2-thiouracil, H(2)L(1) or 6-methyl -2-thiouracil, H(2)L(2)) in the presence of NEt(3) as base in ethanol solvent afforded a trinuclear triangular complex Ru(3)(O,O-acetylacetonate)(3)(mu-O,O,gamma-C-acetylacetonate)(3)(mu(3)-sulfido) (1). In 1, each ruthenium center is linked to one usual O,O-bonded terminal acetylacetonate molecule whereas the other three acetylacetonate units act as bridging functions: each bridges two adjacent ruthenium ions through the terminal O,O-donor centers at one end and via the gamma-carbon center at the other end. Moreover, there is a mu(3)-sulfido bridging in the center of the complex unit, which essentially resulted via the selective cleavage of the carbon-sulfur bond of the thiouracil ligand. In diamagnetic complex 1, the ruthenium ions are in mixed valent Ru(III)Ru(III)Ru(II) state, where the paramagnetic ruthenium(III) ions are antiferromagnetically coupled. The single crystal X-ray structure of 1 showed two crystallographically independent C(3)-symmetric molecules, Ru(3)(O,O-acetylacetonate)(3)(mu-O,O,gamma-C-acetylacetonate)(3)(mu(3)-S) (1), in the asymmetric unit. Bond distances of both crystallographically independent molecules are almost identical, but there are some significant differences in bond angles (up to 6 degrees ) and interplanar angles (up to 8 degrees ). Each ruthenium atom exhibits a distorted octahedral environment formed by four oxygen atoms, two from each of the terminal and bridging acetylacetonate units, one gamma-carbon of an adjacent acetylacetonate ligand, and the sulfur atom in the center of the complex. In agreement with the expected 3-fold symmetry of the complex molecule, the (1)H and (13)C NMR spectra of 1 in CDCl(3) displayed signals corresponding to two types of ligand units. In dichloromethane solvent, 1 exhibited three metal center based successive quasireversible redox processes, Ru(III)Ru(III)Ru(III)-Ru(III)Ru(III)Ru(II) (couple I, 0.43 V vs SCE); Ru(III)Ru(III)Ru(IV)-Ru(III)Ru(III)Ru(III) (couple II, 1.12 V); and Ru(III)Ru(III)Ru(II)-Ru(III)Ru(II)Ru(II) (couple III, -1.21 V). However, in acetonitrile solvent, in addition to the three described couples [(couple I), 0.34 V; (couple II), 1.0 V; (couple III), -1.0], one irreversible oxidative response (Ru(III)Ru(III)Ru(IV) --> Ru(III)Ru(IV)Ru(IV) or oxidation of the coordinated sulfide center) appeared at E(pa), 1.50 V. The large differences in potentials between the successive couples are indicative of strong coupling between the ruthenium ions in the mixed-valent states. Compound 1 exhibited a moderately strong charge-transfer (CT) transition at 654 nm and multiple ligand based intense transitions in the UV region. In the Ru(III)Ru(III)Ru(III) (1(+)) state, the CT band was slightly blue shifted to 644 nm; however, the CT band was further blue shifted to 520 nm on two-electron oxidation to the Ru(III)Ru(III)Ru(IV) (1(2+)) state with a reduction in intensity.     

Photoinduced energy transfer coupled to charge separation in a Ru(II)-Ru(II)-acceptor triad

The bichromophoric system Ru-Ru(C)-PI ([(bpy)3Ru-Ph-Ru(dpb)(Metpy-PI)][PF6]3, where bpy is 2,2'-bipyridine, Hdpb is 1,3-di(2-pyridyl)-benzene, Metpy is 4'-methyl-2,2':6',2' '-terpyridine and PI is pyromellitimide) containing two Ru(II) polypyridyl chromophores with a N6 and a N5C ligand set, respectively, was synthesized and characterized. Its photophysical properties were investigated and compared to those of the monochromophoric cyclometalated complexes Ru(C)-PI ([Ru(dpb)(Metpy-PI)][PF6]), Ru(C)-phi-PI ([Ru(dpb)(ttpy-PI)][PF6], ttpy is 4'-p-tolyl-2,2':6',2' '-terpyridine), Ru(C)-phi ([Ru(dpb)(ttpy)][PF6]), and Ru(C) ([Ru(dpb)(Metpy)][PF6]). Excitation of the Ru(C) unit in the dyads leads to oxidative quenching, forming the Ru(C)(III)-phi-PI*- and Ru(C)(III)-Pl.- charge-separated (CS) states with k(f)(ET) = 7.7 x 10(7) s(-1) (CH3CN, 298 K) in the tolyl-linked Ru(C)-phi-PI and k(f)(ET) = 4.4 x 10(9) s(-1) (CH2Cl2, 298 K) in the methylene-linked Ru(C)-PI. In the Ru-Ru(C)-PI triad, excitation of the Ru(C) chromophore leads to dynamics similar to those in the Ru(C)-PI dyad, generating the Ru(II)-Ru(C)(III)-PI*- CS state, whereas excitation of the Ru unit results in an initial energy transfer (k(EnT) = 4.7 x 10(11) s(-1)) to the cyclometalated Ru(C) unit. Subsequent electron transfer to the PI acceptor results in the formation of the same Ru(II)-Ru(C)(III)-PI*- CS state with k(f)(ET) = 5.6 x 10(9) s(-1) that undergoes rapid recombination with k(b)(ET) = 1 x 10(10) s(-1) (CH2Cl2, 298 K). The fate of the Ru(II)-Ru(C)(III)-PI*- CS state upon a second photoexcitation was studied by pump-pump-probe experiments in an attempt to detect the fully charge-separated Ru(III)-Ru(C)(II)-PI*- state.     

A new structural motif for photoinitiated electron collection: Ru,Rh bimetallics providing insight into H2 production via photocatalysis of water reduction by Ru,Rh,Ru supramolecules

Ru,Rh,Ru complexes are photocatalysts for the reduction of H(2)O to H(2)via a Rh(I) intermediate. The herein reported Ru,Rh bimetallics undergo PEC but do not catalyze the reduction of H(2)O, establishing intact supramolecules are photoactive in the Ru,Rh,Ru systems. The Ru,Rh(I) photoproduct dimerizes via Rh-Rh bond formation, deactivating the Rh(I) center sterically prohibited in the Ru,Rh,Ru trimetallic systems.     

多吡啶钌(Ⅱ)配合物化学发光性质研究

详细研究了Ru(bpy)3^2+,Ru(bpy)2(dppx)^2+,Ru(bpy)2(dppz)^2+,Ru(phen)3^2+,Ru(phen)2(dppx)^2+和Ru(phen)2(dppz)^2+六个多吡啶钌(Ⅱ)配合物的化学发光性质,筛选出Ru(bpy)3^2+和Ru(phen)3^2+两种性能优良的化学发光试剂;并探讨了它们发光的可能机理和影响因素,为钌(Ⅱ)配合物在化学发光分析中的应用提供了可供参考的理论依据。     

Electronic coupling between two cyclometalated ruthenium centers bridged by 1,3,6,8-tetrakis(1-butyl-1H-1,2,3-triazol-4-yl)pyrene

A new bridging ligand 1,3,6,8-tetrakis(1-butyl-1H-1,2,3-triazol-4-yl)pyrene (ttapyr) was designed and synthesized by "click" chemistry. This ligand was used to construct a linear dimetallic biscyclometalated Ru(II) complex [(tpy)Ru(ttapyr)Ru(tpy)](2+) and a monometallic complex [(tpy)Ru(ttapyr)](+), where tpy is 2,2':6',2″-terpyridine. The electronic properties of these complexes were studied and compared by electrochemical and spectroscopic methods with the aid of DFT calculations. One-electron oxidation of [(tpy)Ru(ttapyr)Ru(tpy)](2+) with cerium ammonium nitrate produced a mixed-valent complex [(tpy)Ru(ttapyr)Ru(tpy)](3+). The intramolecular electronic coupling between individual metal centers was quantified by the intervalence charge transfer transition analysis. Mixed-valent complex [(tpy)Ru(ttapyr)Ru(tpy)](3+) exhibits a metal-centered rhombic EPR signal at 77 K with an average g factor of 2.203.     

Can a meso-type dinuclear complex be chiral?: dinuclear β-diketonato Ru(III) complexes

Dinuclear Ru(III) complexes, [Ru(III)(acac)(2)(dabe)Ru(III)(acac)(2)] (acacH = acetylacetone; dabeH(2) = 1, 2-diacetyl-1,2-dibenzoylethane) and [Ru(III)(acac)(2)(tbet)Ru(III)(acac)(2)] (tbetH(2) = 1,1,2,2-tetrabenzoylethane) were synthesized by reacting [Ru(acac)(2)(CH(3)CN)(2)]PF(6) with dabeH(2) and tbetH(2) respectively, in toluene. The X-ray structural analysis of a meso-type dinuclear Ru(III) complex, ΔΛ-[Ru(III)(acac)(2)(dabe)Ru(III)(acac)(2)], showed that the bridging part became chiral due to the orthogonal twisting of two non-symmetrical β-diketonato moieties. To confirm this conclusion, the complex was resolved chromatographically to provide a pair of optical antipodes. Such chirality in the bridging part was not generated for [Ru(III)(acac)(2)(tbet)Ru(III)(acac)(2)], because the β-diketonato moieties in tbet(2-) are symmetrical.     

Sensitization and stabilization of TiO(2) photoanodes with electropolymerized overlayer films of ruthenium and zinc polypyridyl complexes: a stable aqueous photoelectrochemical cell

Overlayer thin films of vinylbipyridine (vbpy)-containing Ru and Zn complexes have been formed on top of ruthenium dye complexes adsorbed to TiO(2) by reductive electropolymerization. The goal was to create an efficient, water-stable photoelectrode or electrodes. An adsorbed-[Ru(vbpy)(2)(dcb)](PF(6))(2)/poly-[Ru(vbpy)(3)](PF(6))(2) surface composite displays excellent stability toward dissolution in water, but the added overlayer film greatly decreases incident photon-to-current conversion efficiencies (IPCE) in propylene carbonate with I(3)(-)/I(-) as the carrier couple. An ads-[Ru(vbpy)(2)(dcb)](PF(6))(2)/poly-[Zn(vbpy)(3)](PF(6))(2) composite displays no loss in IPCE compared to ads-[Ru(vbpy)(2)(dcb)](PF(6))(2) but is susceptible to film breakdown in the presence of water by solvolysis and loss of the cross-linking Zn(2+) ions. Success was attained with an ads-[Ru(vbpy)(2)(dcb)](PF(6))(2)/poly-[Ru(vbpy)(2)(dppe)](PF(6))(2) composite. In this case the electropolymerized layer is transparent in the visible. The composite electrode is stable in water, the IPCE in propylene carbonate with I(3)(-)/I(-) is comparable to the adsorbed complex, and a significant IPCE is observed in water with the quinone/hydroquinone carrier couple. The assembly [(bpy)(2)(CN)Ru(CN)Ru(vbpy)(2)(NC)Ru(CN)(bpy)(2)](PF(6))(2) ([Ru(CN)Ru(NC)Ru](PF(6))(2)) adsorbs spontaneously on TiO(2), and electropolymerization of thin layers of the assembly to give ads-[Ru(CN)Ru(NC)Ru](PF(6))(2)/poly-[Ru(CN)Ru(NC)Ru](PF(6))(2) enhances IPCE and has no deleterious effect on the IPCE/Ru.     

Oxidation behavior of Ru/TiO2 and metallic Ru fine particles on heating in air

Thermogravimetry (TG) and differential thermal analysis (DTA) were used to investigate the oxidation behavior of Ru/TiO2 and metallic Ru fine particles during heating in air in the range 20-1000 degrees C. Temperature ranges of the oxidation for two samples of Ru/TiO2 with the compositions (92 wt% Ru, 8 wt% TiO2) and (75 wt% Ru, 25 wt% TiO2) and for pure metallic Ru fine particle agglomerates were determined. It was assumed that after the partial oxidation of Ru in the sample containing 75 wt% Ru and 25 wt% TiO2 and in the pure metallic Ru a diffusion barrier was formed, preventing further oxidation of Ru in Ru/RuO2 and Ru/RuO2/TiO2 matrices. XRD and TEM were used for the sample characterization.     

Synthesis of ruthenium particles by photoreduction in polymer solutions

Colloidal dispersions of poly(N-vinyl-2-pyrrolidone)-protected ruthenium (Ru) particles have been synthesized by the photoreduction of Ru(III) ionic solutions in the presence of photo-activator such as benzophenone and benzoin. The size and the structure of the synthesized particles have been extensively investigated by UV-vis, transmission electron micrograph (TEM) and extended X-ray absorption fine structure (EXAFS). Metallic Ru particles with an average diameter of 1.3 nm were successfully synthesized in the presence of benzophenone, although mixtures of partly oxidized Ru particles and metallic Ru particles were synthesized in the presence of benzoin. Photoreduction of Ru(III) ionic precursors to Ru atoms was promoted by ketyl radicals, which is more efficiently generated by the photoirradiation of benzophenone than by that of benzoin. The photoirradiation of benzophenone in the Ru(III) ionic solutions is an efficient and convenient method to produce metallic Ru particles in polymer solutions rather than the refluxing and the hydrothermal method of ionic solutions of Ru.     

Ruthenium amino carboxylate complexes as asymmetric hydrogen transfer catalysts

The synthesis and characterization of optically active amino carboxylate complexes of formula [(η(6)-arene)Ru(Aa)Cl] (arene = C(6)H(6), C(6)Me(6), Aa = amino carboxylate) as well as those of the related trimers [{(η(6)-arene)Ru(Aa)}(3)][BF(4)](3) are reported. Trimerization takes place with chiral self-recognition: only diastereomers equally configured at the metal, R(Ru)R(Ru)R(Ru) or S(Ru)S(Ru)S(Ru), are detected. The crystal structures of the complexes [(η(6)-C(6)H(6))Ru(Pip)Cl] and [{(η(6)-C(6)Me(6))Ru(Pro)}(3)][BF(4)](3) have been determined by X-ray diffraction methods. Both types of complexes catalyse the hydrogen transfer reaction from 2-propanol to ketones with moderate enantioselectivity (up to 68% ee). The enantiodifferentiation achieved can be accounted for by assuming that Noyori's bifunctional mechanism is operating.     

Electronic energy transfer and collection in luminescent molecular rods containing ruthenium(II) and osmium(II) 2,2':6',2"-terpyridine complexes linked by thiophene-2,5-diyl spacers

The electronic absorption spectra, luminescence spectra and lifetimes (in MeCN at room temperature and in frozen n-C3H7CN at 77 K), and electrochemical potentials (in MeCN) of the novel dinuclear [(tpy)Ru(3)Os(tpy)]4+ and trinuclear [(tpy)Ru(3)Os(3)Ru(tpy)]6- complexes (3 = 2,5-bis(2,2':6',2'-terpyridin-4-yl)thiophene) have been obtained and are compared with those of model mononuclear complexes and homometallic [(tpy)Ru(3)Ru(tpy)]4+, [(tpy)Os(3)Os(tpy)]4+ and [(tpy)Ru(3)Ru(3)Ru(tpy)]6+ Complexes. The bridging ligand 3 is nearly planar in the complexes, as seen from a preliminary X-ray determination of [(tpy)Ru(3)Ru(tpy)][PF6]4, and confers a high degree of rigidity upon the polynuclear species. The trinuclear species are rod-shaped with a distance of about 3 nm between the terminal metal centres. For the polynuclear complexes, the spectroscopic and electrochemical data are in accord with a significant intermetal interaction. All of the complexes are luminescent (phi in the range 10(-4)-10(-2) and tau in the range 6-340 ns, at room temperature), and ruthenium- or osmium-based luminescence properties can be identified. Due to the excited state properties of the various components and to the geometric and electronic properties of the bridge, Ru --> Os directional transfer of excitation energy takes place in the complexes [(tpy)Ru(3)Os(tpy)]4+ (end-to-end) and [(tpy)Ru(3)Os(3)Ru(tpy)]6+ (periphery-to-centre). With respect to the homometallic case, for [(tpy)Ru(3)Os(3)Ru(tpy)]6+ excitation trapping at the central position is accompanied by a fivefold enhancement of luminescence intensity.     

双核钌配合物中金属间相互作用的电化学研究

应用循环伏安、循环交流伏安和微分电容测定等电化学方法研究了由 2 ,2一联吡啶(bpy)和桥联配体 1,4_二 [2_咪唑并 [4 ,5_f]邻菲咯啉 ]苯 (DIPB)或 1,4_二 [2_脱氢咪唑并 [4,5_f]邻菲咯啉 ]苯 (DIPB_2H)所形成的对称双核钌配合物 (Ru2 :(bpy) 2 Ru(DIPB)Ru(bpy) 2 (ClO4 ) 4 和Ru2_2H :(bpy) 2 Ru(DIPB_2H)Ru(bpy) 2 (ClO4 ) 2 )在铂电极上的电化学性质以及金属间的相互作用 .研究结果表明 ,在 0 .1mol/L高氯酸四丁基铵 (TBAP)的乙腈溶液中 ,中心离子在循环伏安图上均呈现 1对可逆的 2电子氧化还原波 ,电位也几乎不变 ,其所对应的配位阳离子的扩散系数分别为 3.50×10 - 6 cm2 /s和 3.94× 10 - 6 cm2 /s.循环交流伏安和微分电容测定研究发现 ,桥联配体去质子化后 ,中心离子间的电子相互作用增强     

Stepwise assembly of unsymmetrical supramolecular arrays containing porphyrins and coordination compounds

The stepwise coordination of meso-4'-pyridyl/phenyl porphyrins (4'-PyPs) to different metal centers proved to be an efficient synthetic approach leading to unsymmetrical arrays containing porphyrins and coordination compounds. The first step of this process, treatment of 4'-PyPs with a less than stoichiometric amount of cis,fac-RuCl2(Me2-SO)3(CO) (1), leads to the selective coordination of [cis,cis,cis-RuCl2(Me2SO)2(CO)] fragments ([Ru]) to some of the peripheral 4'-N sites of the 4'-PyPs. Column separation afforded four partially ruthenated 4'-PyPs in pure form: 4'-cis-DPyP[Ru] (2), 4'-trans-DPyP[Ru] (3), (4'-TPyP)[Ru] (4), and (4'-TPyP)[Ru]3 (5). These compounds, which have residual unbound peripheral 4'-N(py) sites (either one or three), were allowed to react with other metal centers that may belong either to a metalloporphyrin or to a coordination compound. When building blocks 2-5 were treated with [Ru(TPP)(CO)(EtOH)] (TPP = meso-tetraphenylporphyrin) in chloroform at room temperature, axial coordination of Ru(TPP)(CO) units ((Ru)) to the available 4'-N(py) sites readily occurred, generating the following arrays containing both perpendicular porphyrins and coordination compounds: (Ru)-(mu-4'-cis-DPyP)[Ru], (Ru)(mu-4'-trans-DPyP)[Ru], (Ru)3(mu-4'-TPyP)[Ru], and (Ru)(mu-4'-TPyP)[Ru]3. Furthermore, building blocks 2, 3, and 5 were treated with a series of coordination compounds capable of binding two pyridylporphyrins either cis to each other (trans-RuCl2(Me2SO)4 and trans,cis,cis-RuCl2(Me2SO)2(CO)2) or trans to each other (trans-PdCl2(C6H5CN)2). Homo- (Ru) and heterobimetallic (Ru-Pd) arrays with as many as seven metal atoms (six Ru and one Pd) and two 4'-PyPs were obtained as follows: trans,cis,cis-RuCl2(Me2SO)2(4'-cis-DPyP[Ru])2, trans,cis,cis-RuCl2(Me2SO)2(4'-trans-DPyP[Ru])2, trans,cis,cis-RuCl2(CO)2(4'-cis-DPyP[Ru])2, and trans-PdCl2(4'-TPyP[Ru]3)2. All the products were thoroughly characterized by 1H NMR spectroscopy. Since the [Ru] fragment is chiral, diastereomers are formed when two or more [Ru] units are bound to a porphyrin. We found that when two 4'-cis-DPyP[Ru] (2) units are coordinated cis to each other on the same metal center, the mutual anisotropic effect of the cis porphyrins differentiates the sulfoxide methyl resonances for the two forms. These and other results indicate that the pyridyl units react independently of the presence or absence of a substituent on the other py rings. Thus, the synthetic strategy should be a general method for linking diverse metal centers through pyridylporphyrins.