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Solid-state Structure (solid-state + structure)
Selected AbstractsSolid-State Structure and Tautomerism of 2-Aminotroponimines Studied by X-ray Crystallography and Multinuclear NMR SpectroscopyEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2004Rosa M. Claramunt Abstract Structural studies in the solid state by X-ray crystallography and by 13C and 15N CPMAS NMR spectroscopy carried out on a series of 2-aminotroponimine derivatives 2,5 has allowed to establish the existence of hydrogen bonding and to determine the most stable tautomer. Almost all the structures reflect the classical double-well potential function for the N,H···N hydrogen bonds. Only in the case of the compound N -(pyrrol-1-yl)-2-(pyrrol-1-ylamino)troponimine (5) the crystal structure shows two independent molecules, one with a classical hydrogen bond and another with either a single-well or a low-barrier hydrogen bond. The structure of this compound is discussed with the use of the solid-state NMR spectroscopic data. 2-Aminotropones, as intermediates to the 2-aminotroponimines, show the oxo-tautomer as the stable form. B3LYP/6-31G* calculations are used to rationalise the experimental results. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] 2,3,6,7,10,11-Hexamethoxytribenzotriquinacene: Synthesis, Solid-State Structure, and Functionalization of a Rigid Analogue of CyclotriveratryleneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2004Marco Harig Abstract The syntheses of several tribenzotriquinacenes bearing six methoxy groups at the outer peripheral positions of the aromatic rings are reported. The centro -methyl derivative is accessible in surprisingly good yield through two-fold cyclodehydration in the final step of a synthesis route which requires special care in the preparation of some electron-rich key intermediates, such as 5,6-dimethoxy-2-methylindane-1,3-dione and bis(3,4-dimethoxyphenyl)methanol. X-ray single-crystal structure analysis of the centro -methyl derivative confirms its C3v -symmetrical molecular structure but, at variance from the parent centro -methyltribenzotriquinacene and the similarly shaped cyclotriveratrylene, the hexamethoxytribenzotriquinacene analog does not form columnar stacks in the solid state. Functionalization of the three benzhydrylic bridgehead positions leads to the tetramethyl analog and the bridgehead triol in good yields. In contrast, attempts to functionalize the ortho positions by nitration or bromination mainly give rise to ring cleavage through electrophilic ipso attack, which parallels the behavior of cyclotribenzylenes and cyclotriveratrylenes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Solid-State Structures and Properties of Europium and Samarium HydridesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2010Holger Kohlmann Abstract The structural chemistry of europium and samarium hydrides in the solid state is very rich, ranging from typical ionic hydrides following the hydride-fluoride analogy to complex transition metal hydrides and interstitial hydrides. While crystal structure, electrical, and magnetic properties suggest that europium is divalent in all hydrides investigated so far, samarium is easily transformed to a trivalent oxidation state in its hydrides and shows similarities to other lanthanide(III) hydrides. The problem of neutron absorption of europium and samarium, hampering crystal structure solution and limiting the available structural information, is discussed in detail, and practical solutions for neutron diffraction experiments are given. [source] Identification of Chiral cis- and trans- 2-Stannyloxazolidines by Their NMR Spectra and Solid-State StructuresEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2004Jean-Christophe Cintrat Abstract The assignment of cis and trans configurations in N -protected 4-substituted 2-tributylstannyl-1,3-oxazolidines by NMR has been achieved through the use of extrapolations of Karplus,Kitching-type relationships for 3J(119Sn,C,Z,13C) to establish the shape of the oxazolidine ring. Examination of 3J(H,H) allowed the determination of torsion angles for the substituents on C4 and C5, discrimination being completed by comparison of the H2 chemical shifts, together with the 2J(Sn,C,H2) values. The validity of the method was subsequently corroborated by comparison of the results obtained for the liquid phase with those obtained from radiocrystallographic structures of triphenylstannyl analogues or DFT calculations on trimethylstannyl analogues. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Asymmetrical Fluorene[2,3- b]benzo[d]thiophene Derivatives: Synthesis, Solid-State Structures, and Application in Solution-Processable Organic Light-Emitting DiodesCHEMISTRY - A EUROPEAN JOURNAL, Issue 33 2009Chunyan Du Abstract A series of novel asymmetrical fused compounds containing the backbone of fluorene[2,3- b]benzo[d]thiophene (FBT) were effectively synthesized and fully characterized. Single-crystal X-ray studies demonstrated that the length of the substituent side chains greatly affects the solid-state packing of the obtained fused compounds. DFT, photophysical, and electrochemical studies all showed that the FBTs have large band gaps, low-lying HOMO energy levels, and therefore good stability toward oxidation. Moreover, the substituents strongly influence the fluorescence properties of the resulting FBT derivatives. The di- n -hexyl compound exhibits intense fluorescence in solution with the highest quantum yield of up to 91,%. Solution-processed green phosphorescent organic light-emitting diodes with the di- n -butyl derivative as the host material exhibited a maximum brightness of 14,185,cd,m,2 and a luminescence efficiency of 12,cd,A,1. [source] Solid-state structure and formation of organized molecular films of methacrylate copolymers containing fluorinated and hydrogenated side-chainsPOLYMER ENGINEERING & SCIENCE, Issue 4 2007Atsuhiro Fujimori Surface morphology of monolayers related to solid-state structure for methacrylate comb copolymers having fluorocarbon and hydrocarbon side-chains was investigated by X-ray diffraction (XRD), differential scanning calorimetry, and atomic force microscopy (AFM). From the XRD profiles, two kinds of short spacing peaks were confirmed at 5.0 and 4.2 Ĺ, which assigned the sub-cells for both side-chains. Furthermore, two kinds of endothermic peaks, which corresponded to melting peaks of the both side-chain crystals, appeared in the thermograms. From the AFM observation, it was found that there were hydrogenated domains at a few hundred nanometer diameter in their monolayers, whereas corresponding acrylate copolymer monolayers form the phase-separated structure at 10,30 nm order scales. POLYM. ENG. SCI., 47:354,364, 2007. © 2007 Society of Plastics Engineers. [source] Synthesis and Property Studies of CyclotrisazobenzenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2009Raphael Reuter Abstract Azobenzenophanes are fascinating macrocycles, which are of special interest due to their unique photochromic behavior. Cyclotrisazobenzenes 2 (R = H, Br, tBu) were prepared to probe how much strain the photoisomerization of the azobenzene motive can tolerate. The macrocycles were synthesized in an overall yield of 10,20,% from ortho -phenylenediamine (6). Solid-state structures of cyclotrisazobenzenes 2a and 2b were obtained. Irradiation under various conditions did not induce any isomerization.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Metal Complexes of 4,11-Dimethyl-1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) , Thermodynamic and Formation/Decomplexation Kinetic StudiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2009Ivona Svobodová Abstract The macrocyclic ligand with two methylphosphonic acid pendant arms, 4,11-dimethyl-1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) (1,8-H4Me2te2p, H4L3), was synthesized by a new simple approach. The product of the reaction of quarternized formaldehyde cyclam aminal with the sodium salt of diethyl phosphite was hydrolyzed to give a very high yield of the title ligand. The (H6L3)2+ cation in the solid state is protonated on all ring nitrogen atoms and on each phosphonate group. In the solid-state structure of [Cu(H3L3)][Cu(H2L3)]PF6·3H2O, neutral as well as positively charged complex species are present. Molecular structures of both species are very similar having the copper(II) ion in a coordination environment between square-pyramidal and trigonal-bipyramidal arrangements (, = 0.43 and 0.48) with one pendant arm non-coordinated. The ligand forms stable complexes with transition-metal ions showing a high selectivity for divalent copper atoms. The formation of complexes of the ligand with CuII, ZnII and CdII is fast, confirming the acceleration of complexation due to the presence of the strongly coordinating pendant arms. Acid-assisted decomplexation is fast for all three metal ions. Therefore, the copper(II) complex is not suitable for medicinal applications employing copper radioisotopes, but the title ligand motive can be employed in copper(II) separation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Iminohydroxamato Early and Late Transition Metal Halide Complexes , New Precatalysts for Aluminoxane-Cocatalyzed Olefin Insertion PolymerizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2004Alexander Krajete Abstract We report on new families of non-metallocene metal precatalysts for olefin polymerization with titanium, zirconium, vanadium and nickel as the active metal sites. The novel ligand design concept is based on iminohydroxamic acids and their derivatives as the principal chelating units. Various anionic and neutral [N,O] and [N,N] ligand systems are easily accessible by a modular synthetic sequence of imidoyl chlorides with substituted hydroxylamines or hydrazines, respectively. Steric protection of the metal coordination site, a necessary requirement for suppression of chain termination pathways of non-metallocene catalysts, is brought about by bulky aryl substituents on the imino nitrogen atoms. Crystal structures of some of the hydroxamato ligands reveal interesting intermolecular hydrogen-bridged structures, whereas in the solid-state structure of one titanium precatalyst a five-membered chelate was observed, in line with the design principle of these systems. Preliminary ethylene polymerization studies with methylaluminoxane-activated metal complexes (M = Ti, Zr, V, Ni) show that the most active systems are [N,O]NiBr2 catalysts containing neutral O -alkyl iminohydroxamate ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Understanding the Nature of the States Responsible for the Green Emission in Oxidized Poly(9,9-dialkylfluorene)s: Photophysics and Structural Studies of Linear Dialkylfluorene/Fluorenone Model CompoundsADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Khai Leok Chan Abstract Here, the optical properties of a series of structurally well-defined model compounds for oxidatively degraded poly(dialkylfluorenes) (PFs) are reported. Specifically, linear compounds comprising one, two, or four dihexylfluorene (F) moieties together with one fluorenone (O) moiety placed either at the end or in the center of each chain (i.e., FO, FFO, FOF, FFOFF) are studied. The results support the recent observation that the photophysics of the fluorenone-centered "pentamer" (FFOFF) is most similar to that of oxidized PFs. They further demonstrate that molecule,molecule interaction is essential to activate the green emission band. Investigations by X-ray diffraction (XRD) identify the solid-state structure of a representative member of this class of compounds and reveal inter-molecular interaction through dipole,dipole coupling between neighboring fluorenone moieties. [source] Solution NMR and X-Ray Structural Studies on Phthalocyaninatoiron ComplexesHELVETICA CHIMICA ACTA, Issue 8 2006Ignacio Fernández Abstract The addition of primary amines as solubilizing reagents for phthalocyaninatoiron complexes is shown to afford six-coordinate bis(amine)phthalocyaninato complexes, i.e., [Fe(amine)2(pc)] 2 (amine,=,decan-1-amine) and 3 (amine,=,benzylamine), with the two new N-donors occupying the trans -axial positions. The new complexes were characterized by extensive NMR measurements in THF solution. For complex 3 with the benzylamine ligand, the solid-state structure was determined by X-ray diffraction methods. Complex 2 is sufficiently labile in THF solution to exchange one amine ligand against CO (gas) affording an equilibrium mixture containing [Fe(amine)(CO)(pc)] 4. [source] Simple Chiral Diaminobinaphthyl Dilithium Salts for Intramolecular Catalytic Asymmetric Hydroamination of Amino-1,3-dienesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Julia Deschamp Abstract Simple and easily accessible chiral lithium amide salts are reported as efficient (pre)catalysts for the diastereo- [up to (E:Z)=92:8] and enantioselective [up to 72% ee (E)] hydroamination/cyclisation of conjugated primary aminodienes. These chiral lithium salts are straightforwardly prepared by in situ combination of an N -substituted (R)-(+)-1,1,-binaphthyl-2,2,-diamine ligand and a commercial methyllithium solution. Information on the solid-state structure of these salts was obtained by X-ray analysis of a single crystal. [source] Role of hydrogen bonding in the oxidation potential of enolsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 7 2003Mukul Lal Abstract Three stable ,,,-dimesityl enols with heteroaromatic rings in the ,-position were synthesized to study the effect of OH···N hydrogen bonding on the oxidation potentials of enols. In contrast to its solid-state structure, enol E1 exists predominantly as intramolecularly hydrogen-bonded species in solution. For enol E2 an intermolecular hydrogen bond and for E3 a partial proton transfer were established based on NMR, dilution experiments, solvent dependence and UV,visible spectroscopic studies. Cyclic voltammetric investigations revealed that OH···N hydrogen bonding may shift the oxidation potentials of enols by up to 510,mV cathodically. Copyright © 2003 John Wiley & Sons, Ltd. [source] Controlled vinyl-type polymerization of norbornene with a Nickel(II) diphosphinoamine/methylaluminoxane catalytic systemJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2009Georgios C. Vougioukalakis Abstract A novel nickel-based complex coordinated with an asymmetric diphosphinoamine ligand was synthesized and fully characterized. Single crystals of good quality were also obtained, and the solid-state structure of the complex was studied via X-rays diffraction. The catalytic activity of this Ni(II) complex in the vinyl-type polymerization of norbornene was studied with methylaluminoxane (MAO) as the cocatalyst/activator. The influence of the reaction time, the equivalents of MAO used, and the concentration of the monomer on: (i) the activity of the catalytic system; (ii) the isolated yield of the polymer; and (iii) the molecular weight and molecular weight distribution of the polymer were investigated. The isolated polynorbornene (PNB) yields are significantly higher compared with those reported for other similar nickel-based systems. The as-obtained PNBs are characterized by high molecular weights and relatively narrow and monomodal molecular weight distributions (amongst the narrowest reported in the literature). The linear dependence of the molecular weight of the obtained PNB on the concentration of norbornene points toward a controlled polymerization reaction. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5241,5250, 2009 [source] Changes in lamellar arrangement of crystalline and flexible fluorinated transparent films with drawingPOLYMER ENGINEERING & SCIENCE, Issue 7 2010Atsuhiro Fujimori In recent times, a "crystalline" and flexible optical waveguide candidate with excellent heat-resistance and dimensional stability are developed. For the practical use of this crystalline optical film in the near future, an accurate control of the solid-state structure is indispensable because of the necessity of reducing light refraction at the crystalline/amorphous interface. In this study, changes in the fine structure and lamella arrangement upon drawing poly[tetrafluoroethylene- co -(perfluoroethylvinylether)] (EFA) transparent crystalline films were investigated by using wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) methods. The EFA was crystallized as a lamella crystal in the films and formed a thicker lamella. Upon the drawing of the EFA films, four-point SAXS diagrams developed in the photograph at through direction to the film, which implied that a particular type of layer structure, an alternately tilted lamella arrangement known as the herringbone, was formed. From the result of WAXD and SAXS measurements at edge direction to the film, it is found that formation of isotropic disordered lamella arrangement. Therefore, it is indicated that three-dimensional lamella arrangement in this fluorinated transparent film forms uniaxially cylindrical symmetry. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers [source] Solid-state structure and formation of organized molecular films of methacrylate copolymers containing fluorinated and hydrogenated side-chainsPOLYMER ENGINEERING & SCIENCE, Issue 4 2007Atsuhiro Fujimori Surface morphology of monolayers related to solid-state structure for methacrylate comb copolymers having fluorocarbon and hydrocarbon side-chains was investigated by X-ray diffraction (XRD), differential scanning calorimetry, and atomic force microscopy (AFM). From the XRD profiles, two kinds of short spacing peaks were confirmed at 5.0 and 4.2 Ĺ, which assigned the sub-cells for both side-chains. Furthermore, two kinds of endothermic peaks, which corresponded to melting peaks of the both side-chain crystals, appeared in the thermograms. From the AFM observation, it was found that there were hydrogenated domains at a few hundred nanometer diameter in their monolayers, whereas corresponding acrylate copolymer monolayers form the phase-separated structure at 10,30 nm order scales. POLYM. ENG. SCI., 47:354,364, 2007. © 2007 Society of Plastics Engineers. [source] Synthesis, characterization and single crystal structure determination of aluminum alkoxydisilanolates: precursors for silica,alumina compositeAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2010Mostafa M. Amini Abstract Several novel aluminum alkoxydisilanolate complexes were prepared by reaction of triphenylsilanol with aluminum 2-methoxyethoxide, aluminum 2-ethoxyethoxide, aluminum sec -butoxide and aluminum iso -propoxide. All new complexes, [(Ph3SiO)2Al(OR)]2 [where R = CH2CH2OCH3 (1), CH2CH2OC2H5 (2), CH(CH3)CH2CH3 (3) and CH(CH3)2 (4)] were characterized by elemental analysis, mass spectrometry and infrared spectroscopy (IR), as well as 1H, 13C, 29Si and 27Al NMR spectroscopies. The solid-state structures of the representative compound 2 and 4 were also verified by single-crystal X-ray analyses. Complexes 2 and 4 are dimers having distorted trigonal bipyramidal and tetrahedral coordination at the aluminum center, respectively. The 27Al NMR spectrum of compound 2 showed that the solid-state structure of the complex was not retained in solution, and tetracoordinated aluminum was found in solution in contrast to the pentacoordinated geometry in the solid state. The hydrothermal treatment of 1 and 4 at 200 °C and the subsequent calcination at 1000 °C resulted in the formation of alumina,silica composite (4SiO2·Al2O3) with ,-alumina in the silica matrix. Copyright © 2010 John Wiley & Sons, Ltd. [source] Poly[trans -diaquamanganese(II)-,-(3-pyridinecarboxylato- N:O)-,-(3-pyridinecarboxylato- O:N)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2000Xiang Hao The title complex, [MnII(nic)2(H2O)2]n [nic is 3-pyridinecarboxylate (also called nicotinate), C6H4NO2,], has a two-dimensional layer structure with the unique Mn atom on an inversion centre. In each layer, all nicotinate ligands are coordinated to Mn atoms in a bridging/bidentate mode, thus linking the {MnII(nic)2(H2O)2} monomeric units together to form a dative-bond-based layered polymer. The intra-layer hydrogen bonds involving all water molecules and the carboxylate groups may play an auxiliary part in stabilizing the layer. The layers are arranged in an ordered manner along the a axis through van der Waals forces so as to complete the solid-state structure of the crystal. [source] Copolymerization of Cyclohexene Oxide with CO2 by Using Intramolecular Dinuclear Zinc CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2005Youli Xiao Abstract The intramolecular dinuclear zinc complexes generated in situ from the reaction of multidentate semi-azacrown ether ligands with Et2Zn, followed by treatment with an alcohol additive, were found to promote the copolymerization of CO2 and cyclohexene oxide (CHO) with completely alternating polycarbonate selectivity and high efficiency. With this type of novel initiator, the copolymerization could be accomplished under mild conditions at 1 atm pressure of CO2, which represents a significant advantage over most catalytic systems developed for this reaction so far. The copolymerization reaction was demonstrated to be a living process as a result of the narrow polydispersities and the linear increase in the molecular weight with conversion of CHO. In addition, the solid-state structure of the dinuclear zinc complex was characterized by X-ray crystal structural analysis and can be considered as a model of the active catalyst. On the basis of the various efforts made to understand the mechanisms of the catalytic reaction, including MALDI-TOF mass analysis of the copolymers' end-groups, the effect of alcohol additives on the catalysis and CO2 pressure on the conversion of CHO, as well as the kinetic data gained from in situ IR spectroscopy, a plausible catalytic cycle for the present reaction system is outlined. The copolymerization is initiated by the insertion of CO2 into the ZnOEt bond to afford a carbonate,ester-bridged complex. The dinuclear zinc structure of the catalyst remains intact throughout the copolymerization. The bridged zinc centers may have a synergistic effect on the copolymerization reaction; one zinc center could activate the epoxide through its coordination and the second zinc atom may be responsible for carbonate propagation by nucleophilic attack by the carbonate ester on the back side of the cis -epoxide ring to afford the carbonate. The mechanistic implication of this is particularly important for future research into the design of efficient and practical catalysts for the copolymerization of epoxides with CO2. [source] Dithiolate-Bridged Fe-Ni-Fe Trinuclear Complexes Consisting of Fe(CO)3,n(CN)n (n=0, 1) Components Relevant to the Active Site of [NiFe] HydrogenaseCHEMISTRY - AN ASIAN JOURNAL, Issue 6 2009Satyanarayan Pal Dr. Abstract Step-by-step: A trinuclear Fe-Ni-Fe complex 1 was synthesized from the reaction of [Fe(CO)4I2] with Li2[Ni(norbornane- exo -2,3-dithiolate)2]. The CO ligands in 1 were transformed into CN, upon treatment with ,N(SiMe3)2, and the monocyanide complex 3 and the dicyanide complex 4 were obtained. Complexes 3 and 4 were found to react with protonic acids, whereas 1 is robust. A dithiolate-bridged Fe-Ni-Fe trinuclear carbonyl complex [(CO)3Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (1, ndt=norbornane- exo -2,3-dithiolate) has been synthesized from the reaction of [Fe(CO)4I2] and Li2[Ni(ndt)2]. This reaction was found to occur with concomitant formation of a tetranuclear cluster [Ni3(,-ndt)4FeI] (2). Treatment of 1 with Na[N(SiMe3)2] transforms some of the CO ligands into CN,, and the monocyanide complex (PPh4)[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (3) and the dicyanide complex (PPh4)2[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)2(CN)] (4) were isolated. X-ray structural analyses of the trinuclear complexes revealed a Fe-Ni-Fe array in which the metal centers are connected by the ndt sulfur bridges and direct FeNi bonds. Hydrogen bonding between the CN ligand in 3 and cocrystallized ethanol was found in the solid-state structure. The monocyanide complex 3 and dicyanide complex 4 reacted with acids such as HOTf or HCl generating insoluble materials, whereas complex 1 did not react. [source] Discrete, Base-Free, Cationic Alkaline-Earth Complexes , Access and Catalytic Activity in the Polymerization of LactideEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2010Yann Sarazin Abstract Well-defined, base free cations of zinc and the alkaline-earth metals (Mg, Ca, Sr, Ba) supported by a multidentate phenolate ligand and stabilized by perfluorinated weakly coordinating counterions are readily available by simple procedures; the solid-state structures of the magnesium and calcium derivatives were elucidated. Upon treatment with an excess of iPrOH, these complexes generate highly efficient binary catalytic systems for the immortal ring-opening polymerization of L -lactide, yielding poly(L -lactide)s with controlled architectures and molecular features. [source] Solid-State and Solution Structure of Lanthanide(III) Complexes with a Flexible Py-N6 Macrocyclic LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2009Cristina Núńez Abstract Lanthanide complexes of a hexaaza macrocyclic ligand containing a pyridine head unit (L) were synthesized (Ln = La,Lu, except Pm). The solid-state structures of the corresponding La, Ce, Pr, Nd, and Lu complexes were determined by single-crystal X-ray crystallography, and they reveal the presence of three different mononuclear complexes with three different conformations of the macrocycle and coordination environments around the metal ions. In all complexes the lanthanide ion is coordinated in an endomacrocyclic manner to the six nitrogen donor atoms of the ligand. In the La, Ce, and Pr complexes the metal ions show a 12-coordinate mononuclear environment in which 3 nitrate anions coordinate in a bidentate fashion. However, in the Nd analogue the metal ion displays a 10-coordinated environment with the coordination of 2 bidentate nitrate groups, whereas Lu shows a 9-coordinate environment interacting with 2 nitrate ligands, one of them acting as bidentate and the second one coordinating in a monodentate fashion. The 1H and 13C NMR spectra of the complexes recorded in CD3CN suggest that the complexes adopt in solution a similar structure to that observed for the Nd complex in the solid state. The [Ln(L)(NO3)3] and [Ln(L)(NO3)2]+ complexes were characterized by density functional theory (DFT) calculations (B3LYP model). The structures obtained from these calculations for La, Ce, Pr, and Nd are in good agreement with the experimental solid-state structures. The relative stabilities of the [Ln(L)(NO3)2]+ complexes with respect to the [Ln(L)(NO3)3] ones (Ln = La, Nd, Gd, Ho, or Lu) were studied both in vacuo and in acetonitrile solution (PCM model) at the same computational level. Our calculations indicate that in solution the [Ln(L)(NO3)2]+ species is the most stable one along the whole lanthanide series, in agreement with the NMR spectroscopic data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Isostructural Potassium and Thallium Salts of Sterically Crowded Thio- and Selenophenols: A Structural and Computational StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2008Denis Bubrin Abstract Because of their similar cationic radii, potassium and thallium(I) compounds are usually regarded as closely related. Homologous molecular species containing either K+ or Tl+ are very rare, however. We have synthesized potassium and thallium salts MEAr* [M, E = K, S (2a); K, Se (2b); Tl, S (3a); Tl, Se (3b); Ar* = 2,6-Trip2C6H3, Trip = 2,4,6- iPr3C6H2] derived from terphenyl-substituted thio- and selenophenols. In the solid-state structures of dimeric 2a, 2b, 3a, and 3b additional metal-,n,,-arene interactions to the flanking arms of the terphenyl substituents of different hapticity n are observed. Remarkably, the homologous potassium and thallium complexes 2b and 3b crystallize in isomorphous cells. For 2a, 3a, and model complexes of the composition METph (Tph = C6H4 -2-Trip) the nature of the M,E and M···C(arene) bonding was studied by density functional theory calculations.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis, Coordination and Catalytic Utility of Novel Phosphanyl,ferrocenecarboxylic Ligands Combining Planar and Central ChiralityEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2007Martin Lama Abstract The chiral ferrocene derivative (R,Rp)-2-[1-(diphenylphosphanyl)ethyl]ferrocenecarboxylic acid (1) is prepared together with selected derivatives resulting from modification at the phosphane moiety [P -oxide (5) and P -sulfide (4)] and the carboxyl group {amides bearing benzyl (6) and (R)- or (S)-1-phenylethyl substituents [(R)- 7 and (S)- 7] at the amide nitrogen atom}. Acid 1 and amide 6 are studied as ligands in rhodium and palladium complexes. Bridge cleavage of the dimer [{Rh(,-Cl)Cl(,5 -C5Me5)}2] with 1 gives [RhCl2(,5 -C5Me5)(1 -,P)] (9) containing P-monodentate 1, which undergoes smooth conversion to the (phosphanylalkyl)ferrocenecarboxylato complex [RhCl(,5 -C5Me5){Fe(,5 -C5H5)(,5 -C5H3 -1-CH(Me)PPh2 -2-COO-,2O,P}] (10) upon treatment with silica gel or alumina. Yet another O,P -chelate complex,[Rh{Fe(,5 -C5H5)(,5 -C5H3 -1-CH(Me)PPh2 -2-COO-,2O,P}(CO)(PCy3)] (11; Cy = cyclohexyl) is obtained directly by an acid-base reaction between the acetylacetonato complex [Rh(acac)(CO)(PCy3)] and 1. Amide 6 reacts with [{Pd(,-Cl)(,3 -C3H5)}2] to give the expected phosphane complex [PdCl(,3 -C3H5)(6 -,P)] (12), while the replacement of the cyclooctadiene (cod) ligand in [PdCl(Me)(cod)] affords the chelate complex [PdCl(Me)(6 -,2O,P)] (13). All compounds are characterised by spectroscopic methods and the solid-state structures of 5, 9, 11, 13, (R,Sp)-2-[1-(diphenylphosphoryl)ethyl]-1-[N -(R)-(1-phenylethyl)carbamoyl]ferrocene [(R)- 8; phosphane oxide from (R)- 7], and the synthetic precursors (R,Sp)-1-bromo-2-[1-(diphenylphosphanyl)ethyl]ferrocene (2) and (R,Sp)-1-bromo-2-[1-(diphenylthiophosphoryl)ethyl]ferrocene (3) determined by single-crystal X-ray diffraction. The catalytic properties of 1 and the amides are probed in enanatioselective rhodium-catalysed hydrogenation and palladium-catalysed asymmetric allylic alkylation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Syntheses and Fluxional Processes of Diphenyl(2-thienyl)phosphane Derivatives of Triosmium ClustersEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2006Nitsa K. Kiriakidou Kazemifar Abstract Thermal treatment of [Os3(CO)12] with diphenyl(2-thienyl)phosphane, Ph2P(C4H3S), results in the formation of [Os3(CO)12,x{Ph2P(C4H3S)}x] (x = 1,3, 1,3), but no C,H bond activation was observed. Reaction of [H2Os3(CO)10] with diphenyl(2-thienyl)phosphane at ambient temperature affords [HOs3(,-H)(CO)10{Ph2P(C4H3S)}] (4), but when the samereaction is repeated at elevated temperatures, the cyclometallated species [(,-H)Os3(CO)9{,3 -Ph2P(C4H2S)}] (5) and[(,-H)Os3(CO)8{,3 -Ph2P(C4H2S)}{Ph2P(C4H3S)}] (6) are formed. In addition, two more products, tentatively assigned as [(,-H)Os3(CO)6{,3 -Ph2P(C4H2S)}{,-Ph2P(C4H3S)}{Ph2P(C4H3S)}] (7) and [(,-H)Os3(CO)7{,-Ph2P(C4H2S)}{,-Ph2P(C4H3S)}{Ph2P(C4H3S)}] (8) are obtained. The dynamic behaviours of 2, 5 and 6 have been studied by variable-temperature (VT) 1H and 31P{1H} NMR spectroscopy. The VT 31P{1H} NMR spectra of [Os3(CO)10{Ph2P(C4H3S)}2] (2) demonstrate that a mixture of two isomers, which are in rapid exchange at room temperature, is present and that the less common cis - trans isomer, whose structure has been determined by X-ray crystallography, is favoured for this cluster. The VT 1H NMR spectra of 5 indicate the presence of two isomers which are proposed to arise from an oscillation of the ,,,2 -vinyl group of the thienyl moiety between two metal atoms. A similar fluxional process is proposed to occur in 6 and the assignment of the room-temperature structure(s) of this cluster was confirmed by 1H- 187Os 2D HMQC spectroscopy. In addition to 2, the solid-state structures of 3, 5 and 6 have been determined by X-ray crystallography. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthesis and Structural Characterisation of Palladium and Group-12 Metal Complexes with a Hybrid Phosphanylphosphonate Ferrocene LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2006Abstract Diethyl [1,-(diphenylphosphanyl)ferrocenyl]phosphonate (1) was synthesised by stepwise metallation/functionalisation of 1,1,-dibromoferrocene and studied as a ligand for palladium(II) and group-12 metals. Treatment of [PdCl2(cod)] (cod = ,2:,2 -cycloocta-1,5-diene) with 1 in 1:1 or 1:2 molar ratios gave, respectively, the dinuclear, chloride-bridged complex [{Pd(,-Cl)Cl(1 -,P2)}2] (2) and the mononuclear complex trans -[PdCl2(1 -,P2)2] (3), where 1 coordinates exclusively through the phosphane function. The reactions between 1 and group-12 metal bromides MBr2 in a 1:1 molar ratio gave the adducts [MBr2(1)] [M = Zn (4), Cd (5), and Hg (6)], whose crystal structures change considerably with the metal ion. Thus, whereas 4 is a molecular complex with 1 coordinating as an O1,P2 -chelate, its cadmium(II) analogue is a polymer built up from symmetric {CdBr(,-Br)}2 units interconnected by pairs of O1,P2 -bridging phosphanylphosphonate ligands. Finally, the mercury(II) complex 6 is a halide-bridged dimer, [{Hg(,-Br)Br(1 -,P2)}2]. However, this compound is structurally fluxional in solution (NMR spectra) and, in the crystal, it attains a structure similar to 5 owing to weak interactions between mercury and phosphonate-O1 atoms from adjacent molecules. An isomer to 6, [{HgBr2(1 -,2O1,P2)}2] (7), was isolated from attempted alkylation of 6 and structurally characterised as a dimer, where ligands 1 bridge two {HgBr2} units. All compounds were studied by spectroscopic methods (IR, NMR, mass) and the solid-state structures of 1, 2·,H2O, 3·4,CHCl3, 4, 5, 6·5,C6H6, and 7 have been determined by single-crystal X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Lanthanide Complexes of Disulfoxide Ligands with Varied Configurations: Influence of Lanthanide Contraction on the Structures of the ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2005Jian-Rong Li Abstract Four new disulfoxide-LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3·nH2O with meso -1,3-bis(ethylsulfinyl)propane (meso - L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the LaIII ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2,4 have isostructural dinuclear structures, in which the LnIII ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso -configuration, and monodentate coordination with a rac -configuration. The structural differences between 1 and 2,4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Structural Studies of Lithium Telluro- and Seleno-Phosphorus CompoundsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2003Robert P. Davies Abstract Lithium tellurophosphinite [Ph2PTe][Li(TMEDA)1.33(THF)1.33] (4), ditellurophosphinate, [Ph2PTe2][Li(THF)3.5(TMEDA)0.25] (5), and selenotellurophosphinate [Ph2P(Se)Te][Li(THF)2(TMEDA)] (6) complexes have been prepared from the insertion/oxidation reactions of lithiated secondary phosphanes with elemental chalcogens and characterised by X-ray crystallography. Compounds 4,6 contain no tellurium,lithium bonding interactions in the solid state, instead existing as ion-separated species with THF/TMEDA-solvated lithium cations. Reaction of dilithiated primary phosphanes with more than three equivalents of elemental selenium gives [{(c -C6H11)P(Se)(SeLi)}2·2TMEDA] (7) via a phosphorus-phosphorus coupling reaction. Solid state characterisation of 7 reveals the organo groups in the tetradentate tetraselenohypodisphosphinate ligand to be in an anti conformation to one another and each lithium atom to be coordinated by two selenium atoms, one from each of the diselenophosphinate groups. Multinuclear NMR spectroscopic data are consistent with retention of the solid-state structures of 4,7 in solution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Rigid Bisphenanthrolines: Synthesis, Structure and Self-Assembly at a Solid,Liquid Interface,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2006Michael Schmittel Abstract Several rigid linear bisphenanthrolines with and without bulky groups at the bisimine sites were synthesized. For three representatives, the solid-state structures were elucidated. Their potential for self-assembled monolayers was explored by scanning tunneling microscopy (STM) at the solid,liquid interface, and the resulting architectures were found to be promising candidates for templating metal-ion nanopatterns. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Control of orientation for carbazole group in comb copolymers arranged by method of organized molecular filmsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2007Hiroko Hoshizawa Abstract We investigated the molecular orientation of organized molecular films with regard to solid-state structures for newly synthesized comb copolymers with N -vinylcarbazole (NVCz) by in-plane and out-of plane X-ray diffraction (XRD), differential scanning calorimetry (DSC), and atomic force microscopy (AFM). In the bulk state, hydrogenated and fluorinated comb copolymers form side-chain crystals for a two-dimensional lattice spacing of 4.2 and 5.0,Ĺ, respectively. The findings suggest that the carbazole rings in the main-chain are arranged in opposition to each other. From the results of the DSC measurement, sharp-shaped melting peaks appear on the relatively lower temperature side of the thermograms. This result supports the formation of side-chain crystals in the synthesized comb copolymers. These monolayers of the copolymers on the water surface were extremely condensed, except for the fluorocarbon:NVCz,=,1:1 copolymer. From the in-plane XRD measurement of multilayers on solids, the changes in the two-dimensional lattice structure of fluorinated comb copolymer films containing NVCz units, as opposed to their bulk state, were confirmed. It seems that these structural changes are caused by the stronger ,,, interaction between the carbazole rings rather than the van der Waals interaction between fluorocarbons. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||