Experimental and theoretical study of the regiospecific coordination of RuII and OsII fragments on the lacunary polyoxometalate [alpha-PW11O39]7-

New Ru(II) and Os(II) derivatives of the monovacant [alpha-PW(11)O(39)](7-) anion ([PW(11)O(39){M(DMSO)(3)(H(2)O)}](5-) (M = Ru (1), Os (2)) and [PW(11)O(39){Os(eta(6)-p-cym)(H(2)O)}](5-) (3)) have been synthesized and characterized. The binding mode of the d(6)-{M(II)L(3)(H(2)O)}(2+) moieties in these compounds is similar to that in the previously described [PW(11)O(39){Ru(eta(6)-p-cym)(H(2)O)}](5-) (4) complex: bidentate, on two nonequivalent oxygen atoms of the lacuna, leading to a loss of the C(s) symmetry of the parent anion, which thus plays the role of a prochiral bidentate ligand. The density functional theory (DFT) (B3PW91) computation of the lowest unoccupied molecular orbitals of the {ML(3)(H(2)O)}(2+) (M = Os, Ru; L(3) = fac-(DMSO)(3), eta(6)-C(6)H(6)) fragments reveals the similarities between their electrophilic properties. The origin of the regioselectivity of the grafting was investigated through a DFT (B3PW91) analysis of (i) the highest occupied molecular orbital of [alpha-PW(11)O(39)](7-) and (ii) the relative energies of the different potential regioisomers obtained by a bidentate grafting of the {ML(3)(H(2)O)}(2+) moiety onto the lacuna of [alpha-PW(11)O(39)](7-). The role of the water ligand in the stabilization of this peculiar structure was studied.     

Synthesis, characterization, and photochemical behavior of {Ru(arene)}2+ derivatives of alpha-[PW11O39]7-: an organometallic way to ruthenium-substituted heteropolytungstates

Reaction of [Ru(arene)Cl(2)](2) (arene = benzene, toluene, p-cymene, hexamethylbenzene) with K(7)[PW(11)O(39)].14H(2)O provided two series of organometallic derivatives of heteropolytungstates: type-1 and type-2 complexes of general formulas [PW(11)O(39){Ru(arene)(H(2)O)}](5-) and [{PW(11)O(39){Ru(arene)}}(2){WO(2)}](8-), respectively. All compounds were characterized by infrared and multinuclear NMR ((1)H, (31)P, (183)W) spectroscopies. The crystal structures of Na(4)K(4)[{PW(11)O(39){Ru(benzene)}}(2){WO(2)}].6H(2)O (NaK-2a.6H(2)O), K(7)H[{PW(11)O(39){Ru(toluene)}}(2){WO(2)}].4H(2)O (K-2b.4H(2)O), and Cs(3)K(2)[PW(11)O(39){Ru(p-cymene)(H(2)O)}].4H(2)O (CsK-1c.4H(2)O) were obtained and revealed that the {Ru(arene)} fragment is supported on the oxometallic framework. Photochemical reactivity of [PW(11)O(39){Ru(arene)(H(2)O)}](5-) (arene = toluene, p-cymene) in the presence of various ligands L (L = H(2)O, dimethyl sulfoxide, tetramethylene sulfoxide, and diphenyl sulfoxide) was investigated, and led to the formation of [PW(11)O(39){Ru(L)}](5-), in which the ruthenium is incorporated into the lacunary [PW(11)O(39)](7-) anion.     

Hydrothermal and solid-state transformation of ruthenium-supported Keggin-type heteropolytungstates [XW11O39{Ru(II)(benzene)(H2O)}]n- (X = P (n = 5), Si (n = 6), Ge (n = 6)) to ruthenium-substituted Keggin-type heteropolytungstates

A new pathway for the preparation of mono-ruthenium (Ru)(iii)-substituted Keggin-type heteropolytungstates with an aqua ligand, [PW(11)O(39)Ru(iii)(H(2)O)](4-) (1a), [SiW(11)O(39)Ru(iii)(H(2)O)](5-) (1b) and [GeW(11)O(39)Ru(iii)(H(2)O)](5-) (1c), using [Ru(ii)(benzene)Cl(2)](2) as a Ru source was described. Compounds 1a-1c were prepared by reacting [XW(11)O(39)](n-) (X = P, Si and Ge) with [Ru(ii)(benzene)Cl(2)](2) under hydrothermal condition and were isolated as caesium salts. Ru(benzene)-supported heteropolytungstates, [PW(11)O(39){Ru(ii)(benzene)(H(2)O)}](5-) (2a), [SiW(11)O(39){Ru(ii)(benzene)(H(2)O)}](6-) (2b) and [GeW(11)O(39){Ru(ii)(benzene)(H(2)O)}](6-) (2c), were first produced in the reaction media, and then transformed to 1a, 1b and 1c, respectively, under hydrothermal conditions. Calcination of Ru(benzene)-supported heteropolytungstates, 2a, 2b and 2c, in the solid state produced mixtures of 1a, 1b and 1c with CO (carbon monoxide)-coordinated complexes, [PW(11)O(39)Ru(ii)(CO)](5-) (4a), [SiW(11)O(39)Ru(ii)(CO)](6-) (4b) and [GeW(11)O(39)Ru(ii)(CO)](6-) (4c), respectively. From comparison of their catalytic activities in water oxidation reaction, it was indicated that ruthenium should be incorporated in the heteropolytungstate in order to promote catalytic activity.     

Aqueous speciation studies of europium(III) phosphotungstate

The incorporation of lanthanide ions into polyoxometalates may be a unique approach to generate new luminescent, magnetic, and catalytic functional materials. To realize these new applications of lanthanide polyoxometalates, it is imperative to understand the solution speciation chemistry and its impact on solid-state materials. In this study we find that the aqueous speciation of europium(III) and the trivacant polyoxometalate, PW9O34 9-, is a function of pH, countercation, and stoichiometry. For example, at low pH, the lacunary (PW11O39)7- predominates and the 1:1 Eu(PW11O39)4-, 2, forms. As the pH is increased, the 1:2 complex, Eu(PW11O39)2 11- species, 3, and (NH4)22[(Eu2PW10O38)4(W3O8(H2O)2(OH)4].44H2O, a Eu8 hydroxo/oxo cluster, 1, form. Countercations modulate this effect; large countercations, such as K+ and Cs+, promote the formation of species 3 and 1. Addition of Al(III) as a counterion results in low pH and formation of [Eu(H2O)3(alpha-2-P2W17O61)]2, 4, with Al(III) counterions bound to terminal W-O bonds. The four species observed in these speciation studies have been isolated, crystallized, and characterized by X-ray crystallography, solution multinuclear NMR spectroscopy, and other appropriate tech-niques. These species are 1, (NH4)22[(Eu2PW10O38)4(W3O8(H2O)2(OH)4].44H2O (P; a=20.2000(0), b=22.6951(6), c=25.3200(7) A; alpha=65.6760(10), beta=88.5240(10), gamma=86.0369(10) degrees; V=10550.0(5) A3; Z=2), 2, Al(H3O)[Eu(H2O)2PW11O34].20H2O (P, a=11.4280(23), b=11.5930(23), c=19.754(4) A; alpha=103.66(3), beta=95.29(3), gamma=102.31(3) degrees; V =2456.4(9) A3; Z=2), 3, Cs11Eu(PW11O34)2.28H2O (P; a=12.8663(14), b=19.8235(22), c=21.7060(23) A; alpha=114.57(0), beta=91.86(0), gamma=102.91(0) degrees ; V=4858.3(9) A3; Z=2), 4, Al2(H3O)8[Eu(H2O)3(alpha-2-P2W17O61)]2.29H2O (P; a=12.649(6), b=16.230(8), c=21.518(9) A; alpha=111.223(16), beta=94.182(18), gamma=107.581(17) degrees ; V=3842(3) A3; Z=1).     

Dimerization of mono-ruthenium substituted alpha-Keggin-type tungstosilicate [alpha-SiW11O39RuIII(H2O)]5- to micro-oxo-bridged dimer in aqueous solution: synthesis, structure, and redox studies

We report the dimerization of a mono-ruthenium(III) substituted alpha-Keggin-type tungstosilicate [alpha-SiW(11)O(39)Ru(III)(H2O)](5-) to a micro-oxo-bridged dimer [{alpha-SiW(11)O(39)Ru(m)}2O](n-) (m = III, n = 12; m = IV/III, n = 11; m = IV, n = 10). Single crystal X-ray structure analysis of Rb(10)[{alpha-SiW(11)O(39)Ru(IV)}2O].9.5H2O (triclinic, P1, with a = 12.7650(6) A, b = 18.9399(10) A, c = 20.2290(10) A, alpha = 72.876(3) degrees, beta = 88.447(3) degrees, gamma = 80.926(3) degrees, V = 4614.5(4) A(3), Z = 2) reveals that two mono-ruthenium substituted tungstosilicate alpha-Keggin units are connected through micro-oxo-bridging Ru-O-Ru bonds. Solution (183)W-NMR of [{SiW(11)O(39)Ru(IV)}2O](10-) resulted in six peaks (-63, -92, -110, -128, -132, and -143 ppm, intensities 2 : 2 : 1 : 2 : 2 : 2) confirming that the micro-oxo bridged dimer structure is maintained in aqueous solution. The dimerization mechanism is presumably initiated by deprotonation of the aqua-ruthenium complex [alpha-SiW(11)O(39)Ru(III)(H2O)](5-) leading to a hydroxy-ruthenium complex [alpha-SiW(11)O(39)Ru(III)(OH)](6-). Dimerization of two hydroxy-ruthenium complexes produces the micro-oxo bridged dimer [{alpha-SiW(11)O(39)Ru(III)}2O](12-) and a water molecule. The Ru(III) containing dimer is oxidized by molecular oxygen to produce a mixed valence species [{alpha-SiW(11)O(39)Ru(IV-III)}2O](11-), and further oxidation results in the Ru(IV) containing [{alpha-SiW(11)O(39)Ru(IV)}2O](10-).     

Structural characterization of mono-ruthenium substituted Keggin-type silicotungstates

We have synthesized the mono-ruthenium substituted Keggin-type silicotungstate [SiW(11)O(39)Ru(III)(H(2)O)](5-) (1a) by reaction of the mono-lacunary silicotungstate precursor [SiW(11)O(39)](8-) with Ru(acac)(3) under hydrothermal conditions and isolated as the caesium salt Cs(5)[SiW(11)O(39)Ru(III)(H(2)O)] (1). The DMSO-coordinated complex [SiW(11)O(39)Ru(III)(DMSO)](5-) (2a) was prepared by reaction of 1a with DMSO in aqueous solution at 353 K and isolated as the caesium-potassium mixed salt Cs(4.9)K(0.1)[SiW(11)O(39)Ru(III)(DMSO)] (2). Both compounds 1 and 2 were characterized by single-crystal X-ray structure analysis, powder X-ray structure analysis, UV-Vis spectroscopy, cyclic voltammetry, IR-spectroscopy and elemental analysis. 1 crystallized in the tetragonal space group P4(2)/ncm with a = 20.9299(4), c = 10.3603(4) Angstrom, Z = 4. The ruthenium atom in the Keggin unit could not be distinguished from the tungsten due to disorder. The structural analysis of 2 (monoclinic, P2(1)/c, a = 13.5850(4), b = 20.2764(7), c = 18.1326(4) Angstrom, beta = 90.8730(10) degrees , Z = 4) successfully revealed that the incorporated ruthenium atom is coordinated by DMSO through a Ru-S bond. Polyanion 2a represents the first mono-substituted Keggin ion in which the ruthenium center is not crystallographically disordered. UV-Vis spectroscopy combined with controlled potential electrolysis confirmed that the incorporated rutheniums in 1 and 2 have a valence state of +3. The IR spectra of both 1 and 2 were very similar. All these data indicate that 1 synthesized by reaction of the mono-lacunary silicotungstate K(8)[SiW(11)O(39)] with Ru(acac)(3) under hydrothermal conditions is truly the mono-ruthenium substituted Keggin-type silicotungstate.     

Thermal Properties of the Aquadimethylsulfoxide Complexes [Ln(DMSO)n(H2O)m][Mo3S7Br7] where Ln=Pr,Nd, Eu,Tm

Synthesis, X-ray structural investigation, and study of the thermal properties of new aquadimethylsulfoxide complexes [Ln(DMSO)n(H2O)m][Mo3S7 Br7] containing the rare earth metals (Ln=Pr, Nd, Eu, Tm) were performed. In all complexes DMSO is co-ordinated through the O atoms. Thermal transformations of these salts were studied by quasi-equilibrium thermogravimetry a variant of CRTA (Controlled Rate Thermal Analysis) with constant rate of mass loss (0.3 mg min-1); helium flow keeps the partial pressure of self-generated DMSO/H2O atmosphere ~0.01 atm. [Pr(DMSO)6H2O]X where X=[Mo3S7Br7] decomposes with the formation of the intermediate phases Pr(DMSO)5X at 100-190°C and Pr(DMSO)3X at 250-270°C. Thermal decomposition of [Nd(DMSO)6(H2O)X·CH3CN leads to the intermediate phase Nd(DMSO)5X at 200-210°C. [Eu(DMSO)7(H2O)]X forms the intermediate phases Eu(DMSO)6X at 50-150°C and Eu(DMSO)5X at 190-210°C. Thermal decomposition of [Tm(DMSO)6(H2O)]X gives the intermediate phases Tm(DMSO)5X at 170-200°C and Tm(DMSO)4X at 240-250°C. The further decomposition takes place continuously for all phases. This revised version was published online in July 2006 with corrections to the Cover Date.     

Connecting ruthenium substituted Keggin-type tungstophosphates by oxotungstic bridges: Evidence for the steric effect of {RuL3}2+ (L3 = η6-arene, (DMSO)3) fragments

The intrinsic reactivity of the organoruthenium-grafted tungstophosphates [α-PW₁₁O₃₉{Ru(η⁶-arene)(H₂O)}]^5? and [α-PW₁₁O₃₉{Ru(DMSO)₃(H₂O)}]^5? has been studied as a prerequisite for later catalytic studies. Upon reflux in aqueous solution, they partially transform into [{PW₁₁O₃₉Ru(η⁶-arene)}₂{WO₂}]^8? (when arene = benzene, toluene…) and [α-PW₁₁O₃₉{Ru(DMSO)}]^5?, respectively. In the former case, the conversion is markedly increased by deliberate addition of tungstate: through a solution NMR study, we show that [{PW₁₁O₃₉Ru(η⁶-p-cymene)}₂{WO₂}]^8? is quantitatively obtained by refluxing a 2:1:2 mixture of [α-PW₁₁O₃₉]^7?, [Ru(η⁶-p-cymene)Cl₂]₂ and [WO₄]^2? at pH 3. In contrast, a different type of complex, [{PW₁₁O₃₉Ru(DMSO)₃}₂{(WO₂(H₂O))₂O}]^8?, is formed by reaction of [α-PW₁₁O₃₉{Ru(DMSO)₃(H₂O)}]^5? with tungstate; it has been characterized by single crystal X-ray diffraction analysis of an acidic potassium salt, and by ¹⁸³W solution NMR. The more sterically demanding {Ru(DMSO)₃}²⁺ fragment probably does not allow the formation of [{PW₁₁O₃₉Ru(DMSO)₃}₂{WO₂}]^8?, while connection of {PW₁₁O₃₉Ru(DMSO)₃}^5? subunits is possible through the larger {(WO₂(H₂O))₂O}²⁺ bridge.     

A monovacant heteropolytungstate thioderivative: Synthesis and characterization of [(PW11O39)2(H4Mo4S4O6)](10-) and related isomers

[(PW(11)O(39))(2)(Mo(4)S(4)O(4)(OH(2))(2))](10-) anions were obtained through the stereospecific addition of the [Mo(2)S(2)O(2)](2+) oxothiocation to the monovacant alpha-[PW(11)O(39)](7-) anion. K(10)[(PW(11)O(39))(2)(Mo(4)S(4)O(4)(OH(2))(2))].25H(2)O has been isolated as crystals and characterized by X-ray diffraction. The structure revealed a "sandwich-like" dimer of two alpha-[PW(11)O(39)](7-) subunits assembled by the noteworthy central cluster [H(4)Mo(4)S(4)O(6)]. The crystallization of the crude product produces an isomerically pure compound, which was characterized by (31)P and (183)W NMR. IR data were also supplied. In solution, the compound isomerizes, giving a second diastereoisomer. A kinetic experiment, carried out by (31)P NMR, allowed the conditions of the thermodynamic equilibrium to be determined. A structural relationship between the two isomers is proposed, fully consistent with NMR data. Cisoid and transoid isomers result in the relative disposition of each [PW(11)O(39)](7-) subunit, either staggered or eclipsed. An investigation of the formation of the [Mo(2)O(2)S(2)](2+) unit from the polycondensed cyclic precursor [Mo(10)S(10)O(10)(OH)(10)(H(2)O)(5)] and the aggregation process resulting in the oxothio [(PW(11)O(39))(2)(Mo(4)S(4)O(4)(OH(2))(2))](10-) compound has been undertaken. The studies were monitored by (31)P NMR and UV-vis spectroscopies. The reaction is quantitative in nearly stoichiometric conditions.     

Phenylimido Functionalization of alpha-[PW12O40]3-

A synthetic route of potentially wide scope is reported herein for the organoimido functionalization of polyoxotungstates. This report focuses on the reaction between the monovacant lacunary polyoxotungstate, alpha-((n-C4H9)4N)4H3[PW11O39], and W(NC6H5)Cl4 in anhydrous acetonitrile. Evidence from 1H, 31P, 183W, and 1H-183W HMQC NMR spectroscopy, as well as cyclic voltammetry, electronic absorption, and elemental analysis, is presented for the formation of alpha-[PW12O39(NC6H5)]3- (2) of Cs symmetry, which is structurally related to Td alpha-[PW12O40]3- (3) by formal oxide substitution. The electronic structure of 2 is significantly perturbed from 3 with significant arylimido-->tungsten charge transfer, primarily localized to the W(NC6H5) fragment with secondary charge delocalization onto the remaining W and corner-shared bridging O atoms. This is consistent with the approximately 800 ppm downfield 183W NMR shift for the phenylimido-tungsten, modest cathodic shifts in reversible redox potentials, electronic and IR spectra, and density functional theory calculations.     

Addition of N-heterocyclic carbenes to a ruthenium(VI) nitrido polyoxometalate: a new route to cyclic guanidines

The scope of N-atom transfer from the electrophilic ruthenium(VI) nitrido containing polyoxometalate [PW(11)O(39)Ru(VI)N](4-) has been extended to the N-heterocyclic carbene {CH(2)(Mes)N}(2)C and the coupling product {CH(2)(Mes)N}(2)CNH(2)(+) characterized by (1)H NMR and high-resolution mass spectrometry. Because guanidines display many fields of applications ranging from biology to supramolecular chemistry, this could afford an original route to the synthesis of cyclic guanidines. This also enlarges the potential of nitrido complexes in the synthesis of heterocycles, mainly illustrated in the literature through the formation of aziridines through N-atom transfer to alkenes. In the course of the reaction, the ruthenium(III)-containing polyoxometallic intermediate [PW(11)O(39)Ru(III){NC{N(Mes)CH(2)}(2)}](5-) has been thoroughly characterized by continuous-wave and pulsed electron paramagnetic resonance, which nicely confirms the presence of the organic moiety on the polyoxometallic framework, Ru K-edge X-ray absorption near-edge structure, and electrochemistry.     

Sandwich-type phosphotungstates: structure,electrochemistry, and magnetism of the trinickel-substituted polyoxoanion [Ni(3)Na(H(2)O)(2)(PW(9)O(34))(2)](11-)

The novel nickel-substituted, dimeric phosphotungstate [Ni(3)Na(H(2)O)(2)(PW(9)O(34))(2)](11-) (1) has been synthesized and characterized by IR spectroscopy, elemental analysis, and electrochemistry. X-ray single-crystal analysis was carried out on Na(11)[Ni(3)Na(H(2)O)(2)(PW(9)O(34))(2)].21.25H(2)O, which crystallizes in the triclinic system, space group P1, with a = 12.2467(6) A, b = 16.6031(7) A, c = 22.4017(12) A, alpha = 73.9870(10) degrees, beta = 87.6060(10) degrees, gamma = 79.344(2) degrees, and Z = 2. The polyanion consists of two lacunary B-alpha-[PW(9)O(34)](9-) Keggin moieties linked via three nickel(II) centers and a sodium ion. The structure of 1 is composed of two fused Keggin fragments that represent different Baker-Figgis isomers (alpha- vs beta-type). Electrochemical studies show that 1 exhibits a stable and reproducible voltammetric pattern, with a first wave featuring a chemically reversible four-electron/four-proton process. An investigation of the magnetic properties indicates that the three nickel centers exhibit ferromagnetic exchange interaction.     

Synthesis and characterization of the Keggin-type ruthenium-nitrido derivative [PW11O39{RuN}]4- and evidence of its electrophilic reactivity

The ruthenium-nitrido POM derivative [PW11O39{RuVIN}]4- has been synthesized by reaction between [PW11O39]7- and [RuVINCl5]2- or [RuVINCl4]-. Its molecular structure has been confirmed from multinuclear 31P and 183W NMR spectroscopy together with an EXAFS study, while the oxidation state of the ruthenium bearing the nitrido ligand has been inferred both from 183W NMR and XANES analysis at the Ru-K edge. The potential of [PW11O39{RuVIN}]4- in N-atom transfer reactions has been demonstrated through reaction with triphenylphosphine, which ultimately leads to the release of the bis(triphenylphosphane)iminium cation [PPh3=N=PPh3]+ through several intermediates, among which the phosphoraniminato derivative [PW11O39{RuVNPh3}]3- has been structurally characterized. Its unusual oxidation state is in accordance with its EPR spectrum.     

Strain-controlled, photochemically, or thermally promoted haptotropic shifts of cyclopentadienyl ligands in group 8 metallocenophanes

Cyclopentadienyl (Cp) ligands in moderately strained [1]- and [2]ferrocenophanes [Fe{(eta5-C5H4)2(ERx)y}: Fe{(eta5-C5H4)2SiMe2} (1), Fe{(eta5-C5H4)CH2}2 (10)] and highly strained [2]ruthenocenophanes [Ru{(eta5-C5H4)CR2}2 {R = H (15), Me (16)}] are susceptible to partial substitution by P donors and form mixed-hapticity metallocycles-[M(L2){(eta5-C5H4)(ERx)y(eta1-C5H4)}]: [Fe(dppe){(eta5-C5H4)SiMe2(eta1-C5H4)}] (5), [Fe(dmpe){(eta5-C5H4)SiMe2(eta1-C5H4)}] (6), [Fe(dmpe){(eta5-C5H4)(CH2)2(eta1-C5H4)}] (11), [Ru(dmpe){(eta5-C5H4)(CH2)2(eta1-C5H4)}] (17), [Ru(dmpe){(eta5-C5H4)(CMe2)2(eta1-C5H4)}] (18), and [Ru(PMe3)2{(eta5-C5H4)(CH2)2(eta1-C5H4)}] (19)-through haptotropic reduction of one eta5-, pi-bound Cp to eta1, sigma-coordination. These reactions are strain-controlled, as highly ring-tilted [2]ruthenocenophanes 15 and 16 [tilt angles (alpha) approximately 29-31 degrees ] react without irradiation to form thermodynamically stable products, while moderately strained [n]ferrocenophanes 1 and 10 (alpha approximately 19-22 degrees ) require photoactivation. The iron-containing photoproducts 5 and 11 are metastable and thermally retroconvert to their strained precursors and free phosphines at 70 degrees C. In contrast, the unprecedented ring-opening polymerization (ROP) of the essentially ring-strain-free adduct 6 to afford poly(ferrocenyldimethylsilane) [Fe(eta5-C5H4)2SiMe2]n (Mw approximately 5000 Da) was initiated by the thermal liberation of small amounts of P donor. Unlike reactions with bidentate analogues, monodentate phosphines promoted photolytic ROP of ferrocenophanes 1 and 10. MALDI-TOF analysis suggested a cyclic structure for the soluble poly(ferrocenyldimethylsilane), 8-cyclic, produced from 1 in this manner. While the polymer likewise produced from 10 was insoluble, the initiation step in the ROP process was modeled by isolation of a tris(phosphine)-substituted ring-opened ferrocenophane [Fe(PMe3)3{(eta5-C5H4)(CH2)2(C5H5)}][OCH2CH3] (13[OCH2CH3]) generated by irradiation of 10 and PMe3 in a protic solvent (EtOH). Studies of the cation 13 revealed that the Fe center reacts with a Cp- anion with loss of the phosphines to form [Fe(eta5-C5H5){(eta5-C5H4)(CH2)2(C5H5)}] (14) under conditions identical to those of the ROP experiments, confirming the likelihood of "back-biting" reactions to yield cyclic structures or macrocondensation to produce longer chains.     

Synthesis and Characterization of Heterodinuclear IrCo, RuCo, IrNi, and RuNi Complexes Containing Pyrazolate and Pyrazolylborate Ligands

Treatment of the metallo ligands [ML(pz)(2)(Hpz)] (pz = pyrazolate; L = C(5)Me(5), M = Ir (1); L = mesitylene, M = Ru (3)) with [M'Cl{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (4), Ni (5)) yields heterodinuclear complexes of formula [LM(&mgr;-pz)(2)(&mgr;-Cl)M'{HB(3-i-Pr-4-Br-pz)(3)}] (L = C(5)Me(5); M = Ir; M' = Co (6), Ni (7). L = mesitylene; M = Ru; M' = Co (8)). The related complex [Ru(eta(6)-p-cymene)(pz)(2)(Hpz)] (2) reacts with equimolar amounts of 4 or 5 to give mixtures of the corresponding bis(&mgr;-pyrazolato) &mgr;-chloro complexes [(eta(6)-p-cymene)Ru(&mgr;-pz)(2)(&mgr;-Cl)M'{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (9), Ni (10)) and the triply pyrazolato-bridged complexes [(eta(6)-p-cymene)Ru(&mgr;-pz)(3)M'{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (11), Ni (12)). Complex 1 reacts with 5 in the presence of KOH to give the IrNi complex [(eta(5)-C(5)Me(5))Ir(&mgr;-pz)(3)Ni{HB(3-i-Pr-4-Br-pz)(3)}] (13) whereas its reaction with 4 and KOH rendered the bis(&mgr;-pyrazolato) &mgr;-hydroxo complex [(eta(5)-C(5)Me(5))Ir(&mgr;-pz)(2)(&mgr;-OH)Co{HB(3-i-Pr-4-Br-pz)(3)}] (14). The molecular structure of the heterobridged IrCo complex (6) and those of the homobridged RuNi (12) and IrNi (13) complexes have been determined by X-ray analyses. Compound 6 crystallizes in the monoclinic space group P2(1)/n, with a = 10.146(5) ?, b = 18.435(4) ?, c = 22.187(13) ?, beta = 97.28(4) degrees, and Z = 4. Complex 12 is monoclinic, space group P2(1), with a = 10.1169(7) ?, b = 21.692(2) ?, c = 11.419(1) ?, beta = 112.179(7) degrees, and Z = 2. Compound 13 crystallizes in the monoclinic space group Cc, with a = 13.695(2) ?, b = 27.929(6) ?, c = 13.329(2) ?, beta = 94.11(4) degrees, and Z = 4. All the neutral complexes 6, 12, and 13 consist of linear M.M'.B backbones with two (6) or three (12, 13) pyrazolate ligands bridging the dimetallic M.M' units and three substituted 3-i-Pr-4-Br-pz groups joining M' to the boron atoms. The presence in the proximity of the first-row metal M' of the three space-demanding isopropyl substituents of the pyrazolate groups induces a significant trigonal distortion of the octahedral symmetry, yielding clearly different M'-N bond distances on both sides of the ideal octahedral coordination sphere of these metals.     

Synthesis,structure and in vitro anticancer activity of ruthenium(II) and platinum(II) complexes with chiral aminophosphine ligands

Transition Metal Chemistry - (R)-[Ru(η6-p-MeC6H4iPr)Cl2{Ph2PNHCH(CH3)(C6H4-4-F)}] (1) and cis-(R,R)-[PtCl2{Ph2PNHCH(CH3)(C6H4-4-F)}2] (2) have been obtained by the reaction of the chiral...     

Substitution, cage functionalization, and oxidation of the charge-compensated triruthenium monocarbollide cluster complex [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)6}-closo-2,1-RuCB10H8

The compound [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)6}-closo-2,1-RuCB10H8] 1a reacts with PMe3 or PCy3(Cy = cyclo-C6H11) to give the structurally different species [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)5(PMe3)}-closo-2,1-RuCB10H8] 4 and [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(CO)5(PCy3)}-closo-2,1-RuCB10H8]5, respectively. A symmetrically disubstituted product [1-SMe2-2,2-(CO)2-7,11-(mu-H)2-2,7,11-{Ru2(CO)4(PMe3)2}-closo-2,1-RuCB10H8] 6 is obtained using an excess of PMe3. In contrast, the chelating diphosphines 1,1'-(PPh2)2-Fe(eta-C5H4)2 and 1,2-(PPh2)2-closo-1,2-C2B10H10 react with 1a to yield oxidative-insertion species [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(micro-[1',1'-(PPh2)2-Fe(eta-C5H4)2])(CO)4}-closo-2,1-RuCB10H8] 7 and [1-SMe2-2,2-(CO)2-11-(mu-H)-2,7,11-{Ru2(mu-H)(CO)4(1',2'-(PPh2)2-closo-1',2'-C2B10H10)}-closo-2,1-RuCB10H8] 8, respectively. In toluene at reflux temperatures, 1a with Bu(t)SSBu(t) gives [1-SMe2-2,2-(CO)2-7-(mu-SBu(t))-11-(mu-H)-2,7,11-{Ru2(mu-H)(mu-SBu(t))(CO)4}-closo-2,1-RuCB10H8] 9, and with Bu(t)C [triple bond] CH gives [1-SMe2-2,2-(CO)2-7-{mu:eta2-(E)-CH=C(H)Bu(t)}-11-{mu:eta2-(E)-CH=C(H)Bu(t)}-2,7,11-{Ru2(CO)5}-closo-2,1-RuCB10H8] 10. In the latter, two alkyne groups have inserted into cage B-H groups, with one of the resulting B-vinyl moieties involved in a C-H...Ru agostic bond. Oxidation of 1a with I2 or HgCl2 affords the mononuclear ruthenium complex [1-SMe2-2,2,2-(CO)3-closo-2,1-RuCB10H10] 11.     

1-D链状簇合物[Ni(enMe)_2]_2[Ni(enMe)_2{HMoo_4~(VI)Mo_4~V_8~(VI)VO_(40)(V~VO_4)}]·4H_2O的水热合成和晶体结构

水热合成了一种新的1-D链状四帽pseudo-Keggin 结构钼钒簇合物[Ni(enMe)2]2- [Ni(enMe)2{H MoVI4MoV4VIV8O40(VVO4)}]4H2O 1,X-射线单晶结构分析表明,该晶体属单斜晶系,C2/c空间群。晶体学参数为a = 26.3006(6), b = 13.6195(3), c = 19.7122(5) ,b = 105.8330(10), V = 6793.0(3) ?, Z = 4, Dc = 2.566 g/cm3, Mr = 2623.96, m = 3.507 mm-1, F(000) =5088, R = 0.0700, wR = 0.1529, S = 1.019。该簇合物是由金属配位桥Ni(enMe)2桥联四帽pseudo-Keggin 结构{HMoVI4MoV4VIV8O40(VVO4)}簇构成一维链状结构,链与链间通过与另外一个配位阳离子[Ni(enMe)2]2+的氢键相互作用构成超分子网状结构。     

Diastereoselective Synthesis, Spectroscopy, and Electrochemistry of Ruthenium(II) Complexes of Substituted Pyrazolylpyridine Ligands

We report the synthesis of the hetero- and homoleptic ruthenium(II) complexes Ru(bpy)(2)L(2+), Ru(bpy)L(2)(2+) (bpy is 2,2'-bipyridine), and RuL(3)(2+) of six new bidentates L, the substituted pyrazolylpyridines 1-6 (1-substituted-3-(2-pyridinyl)-4,5,6,7-tetrahydroindazoles with substituents R = H, CH(3), Ph, or C(6)H(4)-4"-COOX where X = H, CH(3), or C(2)H(5)). These were fully characterized by (1)H- and (13)C-NMR spectroscopy and elemental analysis. The UV-visible spectra and redox properties of the complexes, some in the ruthenium(III) and reduced bipyridine oxidation states, are also discussed. The substituents R played a role in determining the stereochemistry of the Ru(bpy)L(2)(2+) and RuL(3)(2+) products. The reaction of Ru(DMSO)(4)Cl(2) with 3 equiv of L bearing aromatic substituents gave only meridional RuL(3)(2+) isomers. The one-step reaction of Ru(bpy)Cl(3).H(2)O with 2 equiv of L provided a mixture of the three possible Ru(bpy)L(2)(2+) isomers, from which one symmetric isomer (labeled beta) was isolated pure. A trans arrangement of the pyrazole groups was deduced by (1)H-NMR and confirmed by X-ray crystallography for one such stereomer (beta-[Ru(bpy)(5)(2)](PF(6))(2), R = C(6)H(4)-4"-COOC(2)H(5)). In contrast, Ru(DMSO)(4)Cl(2) reacted with 2 equiv of L and then 1 equiv of bpy to selectively form the other symmetric isomer (labeled alpha) where the pyridine groups of L are trans. Crystal data for beta-[Ru(bpy)(5)(2)](PF(6))(2) (C(52)H(50)N(8)O(4)F(12)P(2)Ru) with Mo Kalpha (lambda = 0.710 73 ?) radiation at 295 K: a = 28.442(13) ?, b = 18.469(15) ?, c = 23.785(9) ?, beta = 116.76(0) degrees, monoclinic, space group C2/c, Z = 8. Fully anisotropic (except for H and disordered F atoms), full-matrix, weighted least-squares refinement on F(2) gave a weighted R on F(2) of 0.2573 corresponding to R on F of 0.1031 for data where F > 4sigma(F ).