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Organometallic Complexes (organometallic + complex)
Selected AbstractsSingle-Molecule Electroluminescence of a Phosphorescent Organometallic ComplexCHEMPHYSCHEM, Issue 8 2009Yasuhiro Sekiguchi Abstract Lighting one by one: The electroluminescence (EL) from single molecules of a red phosphorescent iridium complex dispersed in a hole-transporting polymer matrix is studied. The single-molecule EL dynamics is determined by local structural inhomogeneities in the matrix polymer (see picture). [source] Theoretical Study on a Class of Organometallic Complexes Based on All-Metal Aromatic Ga3, Through Sandwiching StabilizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2008Li-ming Yang Abstract We report the theoretical study on a class of organometallic complexes containing the all-metal aromatic unit Ga3, on the basis of density functional theory calculations on a series of model sandwich-like compounds [DM(Ga3)]q, as well as those of the saturated compounds [DMn(Ga3)] [D = Ga3,, Cp,(C5H5,); M = Li, Na, K, Be, Mg, Ca] and extended compounds (Cp,)m(Li+)n(Ga3,)o (m, n, and o are integers). For the six metals, the all-metal aromatic Ga3, can only be assembled and stabilized in the "heterodecked sandwich" scheme (e.g. [CpM(Ga3)]q,) so as to avoid cluster fusion. Moreover, we designed a novel class of all-metal aromatic "metalloid" compounds. The ground state heterodecked sandwich species (Cp),(M)q+(Ga3), (M = Li, Na, K, q = 1; M = Be, Mg, Ca, q = 2) and the extended sandwich species (Cp,)m(Li+)n(Ga3,)o are mainly ionic bonded, cluster-assembled "polyatomic molecule", grown from the combination of Cp,, M atoms, and Ga3,. As a prototype for ionic bonding involving intact Ga3, subunits, [CpM(Ga3)]q, may be a stepping stone toward forming ionic, cluster-assembled all-metal aromatic Ga3 -based bulk solids or materials. Additionally, our results for the first time showed that the electronic, structural, and aromatic properties of the all-metal aromatic Ga3, could be well retained during cluster assembly, which is indicative of "building block" character. Bearing the significant difference in bonding patterns between our designed metalloid compounds and the known metalloid species, synthesis of these novel species might present an attractive challenge to experimental chemists. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Organometallic Complexes for Nonlinear Optics.ADVANCED MATERIALS, Issue 22 2009An alkynylruthenium dendrimer exhibits two-photon absorption behavior below 1000,nm, and a nonlinear increase in nonlinearity upon dendrimer growth. Beyond 1000,nm, it undergoes 3PA-induced photochemistry. Its nonlinear optical performance is an order of magnitude greater than that of similar organic dendrimers, demonstrating the performance enhancement possible upon incorporation of metal centers into a molecular architecture. [source] Organometallic Complexes for Nonlinear Optics, 47 , Synthesis and Cubic Optical Nonlinearity of a Stilbenylethynylruthenium Dendrimer,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9-10 2010Christopher J. Jeffery Abstract The synthesis of the 1st generation dendrimer 1,3,5-{trans -[Ru(C,C-3,5-(trans -[Ru(C,CPh)(dppe)2(C,CC6H4 -4-(E)-CHCH)])2C6H3)(dppe)2(C,CC6H4 -4-(E)-CHCH)]}3C6H3 proceeds by a novel route that features Emmons-Horner-Wadsworth coupling of 1,3,5-C6H3(CH2PO(OEt)2)3 with trans -[Ru(C,CC6H4 -4-CHO)Cl(dppe)2] and 1-I-C6H3 -3,5-(CH2PO(OEt)2)2 with trans -[Ru(C,CPh)(C,CC6H4 -4-CHO)(dppe)2] as key steps. The stilbenylethynylruthenium dendrimer is much more soluble than its ethynylated analog 1,3,5-{trans -[Ru(C,C-3,5-(trans -[Ru(C,CPh)(dppe)2(C,CC6H4 -4-C,C)])2C6H3)(dppe)2(C,CC6H4 -4-C,C)]}3C6H3 and, in contrast to the ethynylated analog, is a two-photon absorber at telecommunications wavelengths. [source] 103Rh NMR Chemical Shifts in Organometallic Complexes: A Combined Experimental and Density Functional StudyCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2004Laura Orian Dr. Abstract Experimental 103Rh NMR chemical shifts of mono- and binuclear rhodium(I) complexes containing s - or as -hydroindacenide and indacenediide bridging ligands with different ancillary ligands (1,5-cyclooctadiene, ethylene, carbonyl) are presented. A protocol, based on density functional theory calculations, was established to determine 103Rh NMR shielding constants in order to rationalise the effects of electronic and structural variations on the spectroscopic signal, and to gain insight into the efficiency of this computational method when applied to organometallic systems. Scalar and spin,orbit relativistic effects based on the ZORA (zeroth order regular approximation) level have been taken into account and discussed. A good agreement was found for model compounds over a wide range of chemical shifts of rhodium (,10,000 ppm). This allowed us to discuss the experimental and calculated ,(103Rh) in larger complexes and to relate it to their electronic structure. [source] N -(Aryl)picolinamide Complexes of Ruthenium: Usual Coordination and Strategic CyclometalationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2007Sumon Nag Abstract Reaction of five N -(4- R -phenyl)picolinamides (R = OCH3, CH3, H, Cl, and NO2) with [Ru(PPh3)2(CO)2Cl2] in refluxing 2-methoxyethanol in the presence of a base (NEt3) affords two geometrical isomers of a group of complexes (1-R and 2-R), each of which contains an amide ligand coordinated to the metal center as a monoanionic bidentate N,N donor along with two triphenylphosphanes, a carbonyl, and a hydride. Similar reaction of N -(naphthyl)picolinamide with [Ru(PPh3)2(CO)2Cl2] affords an organometallic complex, 3, in which the amide ligand is coordinated to the metal center, by C,H activation of the naphthyl ring at the 8-position, as a dianionic tridentate N,N,C donor along with two triphenylphosphanes and one carbonyl. Structures of the 1-OCH3, 2-CH3, and 3 complexes have been determined by X-ray crystallography. In all the complexes the two triphenylphosphanes are trans. In the 1-R complexes the hydride is trans to the pyridine nitrogen and in the 2-R complexes it is trans to the amide-nitrogen. All the complexes are diamagnetic, and show characteristic 1H NMR signals and intense MLCT transitions in the visible region. Cyclic voltammetry on all the complexes shows a RuII,RuIII oxidation within 0.71,0.93 V versus SCE. An oxidation and a reduction of the coordinated amide ligand are also observed within 1.29,1.69 V versus SCE and ,1.02 to ,1.21 V versus SCE respectively.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Continuous process for production of hydrogenated nitrile butadiene rubber using a Kenics® KMX static mixer reactorAICHE JOURNAL, Issue 11 2009Chandra Mouli R. Madhuranthakam Abstract A continuous process for hydrogenating nitrile butadiene rubber (NBR) was developed and its performance was experimentally investigated. A Kenics® KMX static mixer (SM) is used in the process as a gas,liquid reactor in which gaseous hydrogen reacts with NBR in an organic solution catalyzed by an organometallic complex such as an osmium complex catalyst. The Kenics® KMX SM was designed with 24 mixing elements with 3.81 cm diameter and arranged such that the angle between two neighboring elements is 90°. The internal structure of each element is open blade with the blades being convexly curved. The dimensions of the SM reactor are: 3.81 cm ID 80 S and 123 cm length and was operated cocurrently with vertical upflow. The NBR solutions of different concentrations (0.418 and 0.837 mol/L with respect to [CC]) were hydrogenated by using different concentrations of the osmium catalyst solution at various residence times. The reactions were conducted at a constant temperature of 138°C and at a constant pressure of 3.5 MPa. From the experimental results, it is observed that a conversion and/or degree of hydrogenation above 95% was achieved in a single pass from the designed continuous process. This is the first continuous process for HNBR production that gives conversions above 95% till date. Optimum catalyst concentration for a given mean residence time to achieve conversions above 95% were obtained. Finally, a mechanistic model for the SM reactor performance with respect to hydrogenation of NBR was proposed and validated with the obtained experimental results. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Mo4(,3 -allyl)4Cl2(OH)2(CO)8: the first cubane-type Mo2+ organometallic complex with ,3 -OH and ,3 -Cl bridgesACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009Tatiana R. Amarante The reaction between fluorenyllithium and Mo(,3 -C3H5)Cl(NCMe)2(CO)2 led to the isolation of di-,3 -chlorido-di-,3 -hydroxido-tetrakis[(,3 -allyl)dicarbonylmolybdenum(II)],9-fluorenone,tetrahydrofuran (1/1/1), [Mo4(C3H5)4Cl2(OH)2(CO)8]·C4H8O·C13H8O. The tetrametallic Mo4 unit constitutes the first example of a complex containing simultaneously two ,3 -OH groups and two ,3 -Cl anions capping the metallic trigonal prism. The four crystallographically independent Mo2+ centres exhibit distorted octahedral geometry with the ,3 -allyl groups being trans -coordinated to a ,3 -OH group and the carbonyl groups occupying the equatorial plane. Space-filling tetrahydrofuran and 9-fluorenone molecules are engaged in strong O,H...O hydrogen-bonding interactions with Mo4(,3 -allyl)4Cl2(OH)2(CO)8 complexes. [source] Theoretical Study on a Class of Organometallic Complexes Based on All-Metal Aromatic Ga3, Through Sandwiching StabilizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2008Li-ming Yang Abstract We report the theoretical study on a class of organometallic complexes containing the all-metal aromatic unit Ga3, on the basis of density functional theory calculations on a series of model sandwich-like compounds [DM(Ga3)]q, as well as those of the saturated compounds [DMn(Ga3)] [D = Ga3,, Cp,(C5H5,); M = Li, Na, K, Be, Mg, Ca] and extended compounds (Cp,)m(Li+)n(Ga3,)o (m, n, and o are integers). For the six metals, the all-metal aromatic Ga3, can only be assembled and stabilized in the "heterodecked sandwich" scheme (e.g. [CpM(Ga3)]q,) so as to avoid cluster fusion. Moreover, we designed a novel class of all-metal aromatic "metalloid" compounds. The ground state heterodecked sandwich species (Cp),(M)q+(Ga3), (M = Li, Na, K, q = 1; M = Be, Mg, Ca, q = 2) and the extended sandwich species (Cp,)m(Li+)n(Ga3,)o are mainly ionic bonded, cluster-assembled "polyatomic molecule", grown from the combination of Cp,, M atoms, and Ga3,. As a prototype for ionic bonding involving intact Ga3, subunits, [CpM(Ga3)]q, may be a stepping stone toward forming ionic, cluster-assembled all-metal aromatic Ga3 -based bulk solids or materials. Additionally, our results for the first time showed that the electronic, structural, and aromatic properties of the all-metal aromatic Ga3, could be well retained during cluster assembly, which is indicative of "building block" character. Bearing the significant difference in bonding patterns between our designed metalloid compounds and the known metalloid species, synthesis of these novel species might present an attractive challenge to experimental chemists. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis and Characterization of Two Novel, Mono-Lacunary Dawson Polyoxometalate-Based, Water-Soluble Organometallic Ruthenium(II) Complexes: Molecular Structure of [{(C6H6)Ru(H2O)}(,2 -P2W17O61)]8,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2006Yoshitaka Sakai Abstract The synthesis and structural characterization of a novel class of mono-lacunary Dawson polyoxometalate-(POM-)based, water-soluble organometallic complexes, which are expected to be effective homogeneous oxidation catalyst precursors in water, is described. The organometallic complexes K8[{(C6H6)Ru(H2O)}(,2 -P2W17O61)]·12H2O (1) and K8[{(p -cymene)Ru(H2O)}(,2 -P2W17O61)]·16H2O (2) were successfully prepared by direct reactions of the mono-lacunary Dawson POM K10[,2 -P2W17O61]·19H2O with the organometallic precursors [(C6H6)RuCl2]2 and [(p -cymene)RuCl2]2, respectively, in aqueous media and characterized by complete elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), and FT-IR and solution (1H, 13C, 31P, and 183W) NMR spectroscopy. The molecular structure of [{(C6H6)Ru(H2O)}(,2 -P2W17O61)]8, (1a), in which the binding of the cationic organometallic group {(C6H6)Ru(H2O)}2+ occurs through two oxygen atoms of the four available oxygen atoms in the mono-lacunary site of the POM, resulting in overall C1 symmetry, was successfully determined by single-crystal X-ray analysis. Interestingly, the hydrophilicity of the organometallic precursors is greatly enhanced by binding to a mono-lacunary Dawson POM with higher hydrophilicity. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Orbital Splitting and Pairing Energy in Open-Shell Organometallics: A Study of Two Families of 16-Electron Complexes [Cp2M] (M = Cr, Mo, W) and [CpM(PH3)] (M = Co, Rh, Ir)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2005Rinaldo Poli Abstract The singlet,triplet gap for two families of 16-electron organometallic complexes has been examined in detail by DFT calculations at the B3LYP level with polarized basis sets on both metal and ligands. For the first family, the group 6 metallocenes (Cp2M with Cp = ,5 -C5H5 and M = Cr, Mo, W), the singlet,triplet gap (ES , ET) is always positive and decreases continuously on going from Cr to Mo to W. For the family of group 9 CpM(PH3), on the other hand, there is a decrease on going from Co to Rh, followed by a slight increase on going further to Ir. These trends have been analyzed in qualitative monoelectronic terms as a function of the competition between the pairing energy and the orbital gap. While the pairing energy decreases as expected in the order 3d >> 4d > 5d, the orbital gap varies in a different way for the two families and, though quantitatively less important, is responsible for the different trends. It is argued that changes in orbital gap are system-dependent for open-shell organometallic systems, thus it is not possible to establish a universal trend of singlet,triplet gaps for a homologous series of complexes with a group of transition metals. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis, Structural and Spectroscopic Characterization of Four [(,6 -PAH)Cr(CO)3] Complexes (PAH = Pyrene, Perylene, Chrysene, 1,2-Benzanthracene)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2004Aldo Arrais Abstract The thermal reaction of hexacarbonylchromium with the polycyclic aromatic hydrocarbons (PAHs) pyrene, perylene, chrysene and 1,2-benzanthracene has afforded four organometallic complexes of the type [(,6 -PAH)Cr(CO)3], whose unprecedented structures were obtained by single-crystal X-ray analysis. The topology of the coordination of the Cr(CO)3 fragment and its asymmetry with respect to the coordinating ring may depend on the opportunity to maintain the maximum aromaticity of the complexed ligand. DFT calculations, 1H NMR, FT-IR and Raman spectroscopy have been used to elucidate the type of interaction between the PAH ligand and the carbonylmetal moiety, giving insight into the ligand-to-metal donor capacity and the intra- and intermolecular interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Cover Picture: Multilayer Polymer Light-Emitting Diodes: White-Light Emission with High Efficiency (Adv. Mater.ADVANCED MATERIALS, Issue 17 200517/2005) Abstract White-light-emitting polymer diodes can be fabricated by solution processing using a blend of luminescent semiconducting polymers and organometallic complexes as the emission layer, and water-soluble (or ethanol-soluble) polymers and/or small molecules as the hole-injection/transport layer (HIL/HTL) and the electron injection/transport layer (EIL/ETL), as reported on p.,2053 by Gong, Bazan, Heeger and co-workers. Illumination-quality light is obtained from these multilayer, high-performance devices, with stable CIE coordinates, color temperatures, and high color-rendering indices all close to those of "pure" white light. The cover illustration envisages the incorporation of the fabrication technique with low-cost manufacturing technology in order to produce large areas of high-quality white light. [source] Cyclopentadienyl technetium (99mTc) tricarbonyl piperidine conjugates: biodistribution and imaging studiesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 9 2001Mouldi Saidi Abstract Synthesis of organometallic complexes of 99mTc using the precursor ligands N -methylpiperidino-4[(bispentahaptocyclopentadienyl)iron] carboxylate and N -(isopropyl)-piperidino-4[(bispentahaptocyclopentadienyl)iron]carboxylate is described. The labelling method involved reaction of the ligands with 99mTcO in the presence of Mn(CO)5Br in dimethyl formamide at 150°C for 1 h in an oil bath. The purification of the complexes was carried out by preparative TLC using ethery/n -butyl methyl amine (95:5) solvent system. The purified complexes were characterized by HPLC using acetonitrile:water (80:20) solvent system in a PRP-1 column in which both the complexes were eluted as single peaks. Biodistribution studies carried out in rats showed 2.4±0.14 and 1.1±0.42% of the injected activity in the brain tissue 5 min p.i. for cytectrene I and II, respectively. The brain to blood activity ratio was >15:1 for both the complexes at 5 min p.i. Scintigraphic studies in rabbits showed significant uptake of the activity in the brain with fast clearance from blood. The complexes warrant further investigation as agents for brain imaging. Copyright © 2001 John Wiley & Sons, Ltd. [source] Transition metal NMR chemical shifts and polarizability effect in organometallic complexesMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2009Alexey N. Egorochkin Abstract The literature data on substituent influence on the 51V, 55Mn, 57Fe, 59Co, 61Ni, 95Mo, 103Rh, 183W, 187Os and 195Pt NMR chemical shifts (,) and on J (M, P; M = Mn, Fe, Mo, Rh, W, Os) coupling constants have been analyzed for 30 series of the organometallic complexes. It has been established for the first time that the , and J values depend on the inductive, resonance and polarizability effects of substituents. The polarizability effect is caused by the partial charge on the central M atom. The contribution of this effect ranges from 3 to 86%. Copyright © 2009 John Wiley & Sons, Ltd. [source] Investigation of structure and dynamics in the sodium metallocenes CpNa and CpNa·THF via solid-state NMR, X-ray diffraction and computational modellingMAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2007Cory M. Widdifield Abstract Solid-state 23Na NMR spectra of two organometallic complexes, cyclopentadienylsodium (CpNa) and the tetrahydrofuran (THF) solvate of CpNa (CpNa·THF), are presented. Analytical simulations of experimental spectra and calculated 23Na electric-field gradient (EFG) tensors confirm that both complexes are present in microcrystalline samples of CpNa recrystallized from THF. For the solvate, 23Na NMR experiments at 9.4 T and 11.7 T elucidate sodium chemical shielding (CS) tensor parameters, and establish that the EFG and CS tensor frames are non-coincident. Single-crystal X-ray diffraction (XRD) experiments are used to determine the crystal structure of CpNa·THF: Cmca (a = 9.3242(15) Ĺ, b = 20.611(3) Ĺ, c = 9.8236(14) Ĺ, , = , = , = 90° , V = 1887.9(5)Ĺ3, Z = 8). For CpNa, 23Na NMR data acquired at multiple field strengths establish sodium CS tensor parameters more precisely than in previous reports. Variable-temperature (VT) powder XRD (pXRD) experiments determine the temperature dependence of the CpNa unit cell parameters. The combination of 23Na quadrupolar NMR parameters, pXRD data and calculations of 23Na EFG tensors is used to examine various models of dynamic motion in the solid state. It is proposed that the sodium atom in CpNa undergoes an anisotropic, temperature-dependent, low frequency motion within the ab crystallographic plane, in contrast with previous models. Copyright © 2007 John Wiley & Sons, Ltd. [source] Electron-density studies of molecular magnetic materialsACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2004Sébastien Pillet For more than forty years, the experimental determination and analysis of electron densities have played a fundamental role in advances in the chemical bond concept. The present paper illustrates the application of this approach to the field of molecular magnetism with examples that recently appeared in the literature. Particular attention is attached to several classes of materials, purely organic free radicals, coordination compounds and organometallic complexes, which exhibit specific magnetic behaviors. It is shown to what extent the electron-density analysis can shed light on bonding aspects that are closely related to magnetic couplings. Relations between spin delocalization, spin polarization, superexchange and the characteristics of the electron density are described. The use of the topological theory of `atoms in molecules' allows the possible magnetic interaction pathways to be located and defined, especially through weak intermolecular contacts. The complementarity with polarized neutron diffraction and spin-density modeling techniques is particularly evident from the chosen examples. [source] Probing the supramolecular interaction synthons of 1-benzofuran-2,3-dicarboxylic acid in its monoanionic formACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009Rajesh Koner 1-Benzofuran-2,3-dicarboxylic acid (C10H6O5) is a dicarboxylic acid ligand which can readily engage in organometallic complexes with various metal ions. This ligand is characterized by an intramolecular hydrogen bond between the two carboxyl residues, and, as a monoanionic species, readily forms supramolecular adducts with different organic and inorganic cations. These are a 1:1 adduct with the dimethylammonium cation, namely dimethylammonium 3-carboxy-1-benzofuran-2-carboxylate, C2H8N+·C10H5O5,, (I), a 2:1 complex with Cu2+ ions in which four neutral imidazole molecules also coordinate the metal atom, namely bis(3-carboxy-1-benzofuran-2-carboxylato-,O3)tetrakis(1H -imidazole-,N3)copper(II), [Cu(C10H5O5)2(C3H4N2)4], (II), and a 4:1 adduct with [La(H2O)7]3+ ions, namely heptaaquabis(3-carboxy-1-benzofuran-2-carboxylato-,O3)lanthanum 3-carboxy-1-benzofuran-2-carboxylate 1-benzofuran-2,3-dicarboxylic acid solvate tetrahydrate, [La(C10H5O5)2(H2O)7](C10H5O5)·C10H6O5·4H2O, (III). In the crystal structure, complex (II) resides on inversion centres, while complex (III) resides on axes of twofold rotation. The crystal packing in all three structures reveals ,,, stacking interactions between the planar aromatic benzofuran residues, as well as hydrogen bonding between the components. The significance of this study lies in the first crystallographic characterization of the title framework, which consistently exhibits the presence of an intramolecular hydrogen bond and a consequent monoanionic-only nature. It shows further that the anion can coordinate readily to metal cations as a ligand, as well as acting as a monovalent counter-ion. Finally, the aromaticity of the flat benzofuran residue provides an additional supramolecular synthon that directs and facilitates the crystal packing of compounds (I),(III). [source] Efficient fuel cell catalysts emerging from organometallic chemistryAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2010Helmut Bönnemann Abstract During the last few decades organometallic methodologies have generated a number of highly effective electrocatalyst systems based on mono- and bimetallic nanosparticles having controlled size, composition and structure. In this microreview we summarize our results in fuel cell catalyst preparation applying triorganohydroborate chemistry, ,reductive particle stabilization' using organoaluminum compounds, and the controlled decomposition of organometallic complexes. The advantages of organometallic catalyst preparation pathways are exemplified with RuPt nanoparticles@C as promising anode catalysts to be used in direct methanol oxidation fuel cells (DMFC) or in polymer electrolyte fuel cells (PEMFC) running with CO-contaminated H2 as the feed. Recent findings with highly efficient PtCo3@C fuel cell catalysts applied for the oxygen reduction reaction (ORR) and with the effect of Se-doping on Ru@C ORR catalysts clearly demonstrate the benefits of organometallic catalyst synthesis. Copyright © 2010 John Wiley & Sons, Ltd. [source] Structural and Nonlinear Optical Properties of Aligned Heterotrinuclear [RuII -(Spacer)-MII -(Spacer)-RuII] Complexes (M=Pd, Pt; spacer=4-ethynylpyridine)CHEMISTRY - AN ASIAN JOURNAL, Issue 6 2009Qingchun Ge Abstract Optical alloy: "Linear" heterotrinuclear assemblies, with the metals separated by 4-ethynylpyridine spacers [RuCp(CCpy-4)(dppf)]2[MCl2] (M=Pd, Pt), have been structurally identified. They are electrochemically active and show good cubic nonlinear optical responses. Lewis addition between the metalloligand [RuCp(CCpy-4)(dppf)] (1) (dppf=(C5H4PPh2)2Fe) and MCl2(CH3CN)2 gives [RuCp(CCpy-4)(dppf)]2[MCl2] (M=Pd (2) and Pt (3)), all of which have been spectroscopically and crystallographically characterized. The mixed-metal adducts show the d6 -d8 -d6 metal alignment maintained by the trans disposition of the directionally rigid 4-ethynylpyridine at the centrosymmetric square-planar metal center. Electrochemical studies of these and the related known complexes trans -[RuCl(CCpy-4)(dppm)2] (4) and [trans -RuCl(CCpy-4)(dppm)2]2[MCl2] (dppm=Ph2PCH2PPh2) (M=Pd (5) and Pt (6)) suggest that the spacer-linked heterotrinuclear network is able to stabilize the oxidized RuIII better than the metalloligand precursor. Cubic nonlinear optical responses are also generally higher for the heterometallic complexes. The ,real value of the PdRu2 dppm complex 5 is among the largest for linear organometallic complexes. [source] Medicinal Organometallic Chemistry: Designing Metal Arene Complexes as Anticancer AgentsCHEMISTRY - AN ASIAN JOURNAL, Issue 11 2008Abstract The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon-bound and other ligands allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure,activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed. [source] The Presence of a Ferrocenyl Unit on an Estrogenic Molecule is Not Always Sufficient to Generate in,vitro CytotoxicityCHEMMEDCHEM, Issue 11 2006Anne Vessičres Dr. Abstract We recently reported the dual (antihormonal and cytotoxic) functionality of ferrocifens, which are organometallic complexes derived from hydroxytamoxifen, the standard molecule in the treatment of hormone-dependent breast cancers. To test the hypothesis that the presence of a ferrocenyl substituent on molecules with an affinity for the estrogen receptor is sufficient to give them cytotoxic properties in,vitro, we prepared complexes derived from estradiol with a ferrocenyl substituent at positions 7, and 17,. The complexes thus obtained retain a satisfactory level of affinity for the estrogen receptor (RBA values higher than 12,%). At low concentrations (0.1,1,,M) the complexes show an estrogenic effect in,vitro equivalent to that of estradiol on hormone-dependent (MCF-7) breast cancer cells, and no cytotoxic effect on hormone-independent (MDA-MB-231) breast cancer cells. At high concentrations (up to 50,,M) the 17, -ethynylferrocenyl estradiol and 7, -ferrocenylmethylthio estradiol become cytotoxic (IC50=13.2,,M and 18.8,,m, respectively) while the 17, -ferrocenylestradiol remains non toxic. The low toxicity of these compounds support our hypothesis that electronic communication between the ferrocenyl and phenol moieties in the hydroxyferrocifens series is a key parameter in the generation of cytotoxic effects at submicromolar concentrations. [source] | |||||||||||||||||||||||||