Synthesis and Crystal Structure of Amino Acid Modified NDI Lanthanide Coordination Complex

The synthesis and crystal structure of γ‐aminobutyric acid naphthalene diimides derivative with the La^III coordination complex, [La(L)(DMF)Cl]_n, was reported, which is a twofold interpenetrating metal‐organic framework architecture. The coordination polymer was characterized by elemental analysis, infrared spectroscopy, thermal gravimetric analysis, and single‐crystal X‐ray diffraction. The optical properties of the crystallized complex were investigated both in solution and the solid state.     

Solid-state polymerization of butadienes. Crystal structure and solution properties of a stereoregular amphoteric 1,4-trans-polybutadiene

The double salt 1 consisting of the hydrochloride of 6-amino-2,4-trans-hexadienoic acid and cadmium chloride in a 2:1 stoichiometry polymerizes in the crystalline state if exposed to UV or γ irradiation. A stereoregular polymeric ampholyte is formed in an extended chain macroconformation, embedded in an inorganic matrix. The crystal structure of the polymerized crystals and the solution properties of the polymer are reported. Polymerized crystals are triclinic, space group P1 , a = 7.2144 Å, b = 7.2447 Å, c = 18.5936 Å, α = 104.49°, β = 96.631°, γ = 95.706°, Z = 2. The structure consists of 2-dimensional layers of polymer and inorganic CdCl₆ octahedra alternatively stacked in the third dimension. The cadmium ions can be separated from the polymer by a precipitation as insoluble CdS. After separation from the inorganic material the polymer is soluble in strong acids and bases and insoluble in neutral water. From viscosity measurements of alkaline solutions of the polymer, an average molar mass of 4 × 10⁴ g/mol can be deduced. The polymer selectively adsorbs divalent transition metal ions if suspended in an aqueous solution of transition metal salts. The structure of the resulting polymer–metal complexes is discussed.     

The use of high-energy shock wave treatment as pre-activation of sintering high-entropy solid solutions of transition metal borides and carbides

Synthesis of solid solutions of transition metal borides (NbB₂, TaB₂, HfB₂ and ZrB₂) and carbides (NbC, TaC, HfC, ZrC and VC) was carried out via sintering the individual components without applying pressure. To activate the interaction of the components, the initial powders were processed by high-energy shock wave treatment (HESWT). HESWT enables the formation of homogeneous solid solution for a mixture of carbides; however, this method did not give the desired results for a mixture of transition metal borides, likely due to the higher strength of borides crystal lattice in comparison with carbides.     

Ternary Sulfides: Model Compounds for the Correlation of Crystal Structure and Magnetic Properties

Relationships between crystal structure and magnetic properties enable an insight into the nature of the binding of atoms or ions in the solid state. Suitable as model substances are transition metal compounds in which the collective bonds that are generally present are directively degraded by incorporation of diamagnetic cations. This requirement of progressive degradation is met with in sulfides of the general composition A_xM_yS_z, where A ? alkali metal and M ? transition metal.     

Quantitative vs. qualitative approaches to the electronic structure of solids

The usefulness of qualitative and quantitative theoretical approaches in solid state chemistry is discussed by considering three different types of problems: (a) the distribution of boron and carbon atoms in MB₂C₂ (M=Ca, La, etc.) phases, (b) the band structure and Fermi surface of low-dimensional transition metal oxides and bronzes, and (c) the correlation between the crystal and electronic structure of the ternary nitride Ca₂AuN.     

一种新型低带隙共轭聚合物的合成及其光学性质

在钯催化剂作用下, 通过4,7-二(5-溴-2-噻吩基)[2,1,3]苯并噻二唑与2,5-二乙炔基-3-辛基噻吩的偶联反应, 合成了一种新的共轭高分子聚4,7-二(2-噻吩基)苯并噻二唑-3-辛基噻吩二炔(PTE-DTBT). 通过紫外可见吸收光谱及荧光光谱对其光学性质进行了研究. 紫外-可见吸收谱结果表明, PTE-DTBT的固体膜光学带隙为1.71 eV; 电化学测试其带隙为1.88 eV. TiO₂/PTE-DTBT共混固体膜的荧光发射谱结果表明电子供体PTE-DTBT分子与电子受体TiO₂分子间存在有效的电子转移.     

Synthesis, characterization, and single crystal X-ray structures of [CoIII((BA)2en)(thiobenzamide)2]PF6 and [CoIII(acacen)(thiobenzamide)2]ClO4 and their solvatochromic properties

New cobalt(III) complexes of two tetradentate Schiff base ligands, acacen = bis(acetylacetone)ethylenediimine dianion and (BA)₂en = bis(benzoylacetone)-ethylenediimine dianion, with two axial thiobenzamide (tb) ligands have been synthesized by solid state methods and characterized by elemental analyses, IR, UV–Vis, and ¹H-NMR spectroscopy. Both complexes show solvatochromism in a variety of solvents. The crystal and molecular structures of (1) and (2) were determined by X-ray crystallography. The structure (1) contains two independent [Co^III((BA)₂en)(tb)₂]⁺ complexes, two independent PF₆ anions, and one well ordered ethyl acetate solvent molecule per asymmetric unit. In contrast, the structure (2) contains two independent [Co^III(acacen)(tb)₂]⁺ complexes of C₂ symmetry, a disordered ClO₄ group and disordered toluene molecules. The octahedral coordination of Co(III) is distorted and the Schiff base ligands (ONNO donors) coordinate the cobalt ion in four equatorial positions, and the two axial positions are occupied by S-bonded thiobenzamide molecules. Intramolecular N–H···O hydrogen bonds donated by the thiobenzamide molecules add to the stability of the complexes in the solid state. The IR, UV–Vis, and ¹H-NMR spectra of the two complexes and their solvatochromic properties are also discussed. The compounds exhibit LLCT mediated by the metal center. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis, crystal structure and luminescent properties of a new 3D coordination polymer constructed by Cd(II) with 4,4′-oxybis(benzoate) and 4,4′-bipyridine

A new Cd(II) coordination polymer, [Cd(bpy)(oba)] _n (1) (H₂oba = 4,4′-oxybis(benzoic acid); bpy = 4,4′-bipyridine) has been synthesized under the hydrothermal conditions and structurally characterized by elemental analysis, IR spectrum and single crystal X-ray diffraction. X-ray diffraction analysis reveals that 1 features an interesting 3D framework with wavelike [Cd₂(oba)₂] _n ribbons linked by 4,4′-bpy bridges. The oba ligand adopts chelating and chelating/bridging coordination modes. 1 displays strong fluorescent emission in the solid state at room temperature. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Theoretical study of first-row transition metal porphyrins and their carbonyl complexes

The equilibrium geometry, relative energies, normal mode frequencies, and electron and spin density distributions for first-row transition metal porphyrins M(P) (M is a transition metal in the oxidation state +2, P = C₂₀H₁₂N₄) and their five-and six-coordinate carbonyl complexes M(P)CO and M(P)(CO)(AB) (AB = CO, CN^?, CS) in different spin states have been calculated by the density functional theory B3LYP method with the 6-31G and 6-31G* basis sets. The energies of binding of the CO group to M(P) molecules D(M-CO) have been estimated. The calculated properties change as a function of the metal, the number of carbonyl groups (shown for Fe(P) as an example), and the multiplicity. Calculations show that, for five-coordinate complexes M(P)CO with M = Ti and V, high-spin states and significant D(M-CO) energies are typical. For Fe(P)CO, a singlet with a small D(M-CO) energy is preferable. For Cr(P)CO and Mn(P)CO (which also have small D(M-CO) energies), the states with different spins, which strongly differ in geometry and electronic structure, are close in energy, within 0.1–02. eV. The energy of binding of CO to M(P)CO (M = Cr, Mn, Fe) is considerably higher than the energy of binding of CO to M(P), which is evidence that the transformation of five-coordinate metalloporphyrins into six-coordinate ones is energetically favorable. The behavior of the D(M-CO) energies is interpreted using a qualitative model that considers not only the effects of participation (or nonparticipation) of “active” $ d_{x^2 - y^2 } The equilibrium geometry, relative energies, normal mode frequencies, and electron and spin density distributions for first-row transition metal porphyrins M(P) (M is a transition metal in the oxidation state +2, P = C₂₀H₁₂N₄) and their five-and six-coordinate carbonyl complexes M(P)CO and M(P)(CO)(AB) (AB = CO, CN⁻, CS) in different spin states have been calculated by the density functional theory B3LYP method with the 6-31G and 6-31G* basis sets. The energies of binding of the CO group to M(P) molecules D(M-CO) have been estimated. The calculated properties change as a function of the metal, the number of carbonyl groups (shown for Fe(P) as an example), and the multiplicity. Calculations show that, for five-coordinate complexes M(P)CO with M = Ti and V, high-spin states and significant D(M-CO) energies are typical. For Fe(P)CO, a singlet with a small D(M-CO) energy is preferable. For Cr(P)CO and Mn(P)CO (which also have small D(M-CO) energies), the states with different spins, which strongly differ in geometry and electronic structure, are close in energy, within 0.1–02. eV. The energy of binding of CO to M(P)CO (M = Cr, Mn, Fe) is considerably higher than the energy of binding of CO to M(P), which is evidence that the transformation of five-coordinate metalloporphyrins into six-coordinate ones is energetically favorable. The behavior of the D(M-CO) energies is interpreted using a qualitative model that considers not only the effects of participation (or nonparticipation) of “active” , and , d _xz , and d _yz AO in bonding of M to the P ring and axial ligands, but also the fraction of the total bond energy consumed for the preparation (promotion) of those “valence states” of the M(P) molecules that are realized in M(P)CO and M(P)(CO)(AB) complexes. For the series of compounds Fe(P)(CO)₂ − Fe(P)(CO)(CS) − Fe(P)(CS)₂ − Fe(P)(CO)(CN⁻) in the singlet, triplet, and ionized states, the trans influence of axial ligands in low-spin metalloporphyrins is shown to follow the same qualitative scheme as is typical of octahedral transition metal complexes: in mixed-ligand complexes (as compared to the symmetric ones), the stronger bond becomes shorter and even stronger, while the weaker bond becomes longer and even weaker. It is assumed that the same scheme will persist for more complicated low-spin six-coordinate metalloporphyrins in the states with the vacant AO and occupied d _xz and d _xz AOs involved in bonding with both axial ligands with the filled shell. Original Russian Text ? O.P. Charkin, A.V. Makarov, and N.M. Klimenko, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 5, pp. 781–794.     

Synthesis and crystal structure determination of the triflate salt of diacetonitrile(2,2′-bipyridine)platinum(II)

Reaction of [Pt(bipy)Cl₂] (bipy = 2,2′-bipyridine) with an excess of silver triflate in refluxing acetonitrile readily affords [Pt(bipy)(MeCN)₂](CF₃SO₃)₂ as a yellow, crystalline solid. A single crystal X-ray diffraction study shows that the cations are arranged in a zig-zag manner in rows parallel to the b axis of the monoclinic unit cell. Consideration of the crystal structures of related bipyridyl ligand complexes of platinum(II), leads to the conclusion that a stacked structure with intermolecular Pt…Pt interactions for the title compound is prevented by the electrostatic repulsion between adjacent cations that are doubly charged.     

由2-(4'-羧基苯基)咪唑-4,5-二羧酸构筑的过渡金属配位聚合物的合成、结构及性质

在溶剂热条件下,由2-(4′-羧基苯基)咪唑-4,5-二羧酸(H_4L,C_(12)H_8N_2O_6),合成了4个配位聚合物{[M(H_3L)_2]·2H_2O}_n(M=Zn(1),Cd(2),Co(3)),[Cd(H_2L)(H_2O)]_n(4)。用元素分析、红外光谱、热重分析和单晶X射线衍射对配合物进行了表征和结构分析。结构分析结果表明:1～3是异质同晶。配体失去1个质子以H_3L~-的形式通过单齿和N,O-双齿螯合的配位模式与中心金属离子配位,构成一个略有变形的八面体结构。对于配合物4来说,配体失去2个质子以H_2L~(2-)的形式分别通过单齿和N,O-双齿螯合的配位方式与Cd~(2+)配位,中心离子采取扭曲的七配位五角双锥配位模式,并且通过配体苯环上羧基氧原子的双齿桥联作用连接2个中心离子,形成四元环的双核结构;同时呈现双节点(3,6)-连接的二维拓扑网络(4.4.4)(4.4.4.4.4.4.5.6.6.6.6.6)。测定了产物的固体荧光光谱;用EtBr荧光探针法研究了配体及配合物与ct-DNA的相互作用。     

Electronic band structures and photovoltaic properties of MWO4 (M=Zn, Mg, Ca, Sr) compounds

Divalent metal tungstates, MWO₄, with wolframite (M=Zn and Mg) and scheelite (M=Ca and Sr) structures were prepared using a conventional solid state reaction method. Their electronic band structures were investigated by a combination of electronic band structure calculations and electrochemical measurements. From these investigations, it was found that the band structures (i.e. band positions and band gaps) of the divalent metal tungstates were significantly influenced by their crystal structural environments, such as the W-O bond length. Their photovoltaic properties were evaluated by applying to the working electrodes for dye-sensitized solar cells. The dye-sensitized solar cells employing the wolframite-structured metal tungstates (ZnWO₄ and MgWO₄) exhibited better performance than those using the scheelite-structured metal tungstates (CaWO₄ and SrWO₄), which was attributed to their enhanced electron transfer resulting from their appropriate band positions.     

Hydrothermal synthesis,structure and properties of a novel Zn(II) dicarboxylate containing nanometer channel by significant hydrogen bonds and π–π interactions

A two-dimensional supramolecular complex, [Zn(HA)₂(hmta)] · 2H₂O (1) (H₂A: 9-ethylcarbazole-3,6-dicarboxylic acid, hmta: 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane), has been prepared by hydrothermal synthesis and characterized by IR spectra, elemental analysis, TG analysis. The result of single crystal X-ray analysis revealed that the 2D supramolecular open framework contains 9.932 × 12.059 Å channels formed by significant hydrogen bonds and π–π interactions. Furthermore, the solid state fluorescent determinations show that the complex exhibits a strong emission band at 432 nm.     

Iron-Semiquinone, Semiquinone-Semiquinone, and Iron-Iron Magnetic Exchange in Monomeric and Dimeric Ferric Complexes Containing the 3,6-Di-tert-butyl-1,2-semiquinonate Ligand

Fe(3,6-DBSQ)(3) has been prepared by reacting 3,6-di-tert-butyl-1,2-benzoquinone with Fe(CO)(5). The complex has been characterized structurally [orthorhombic, Pbca, a = 18.277(5) ?, b = 11.634(3) ?, c = 39.903(10) ?, V = 8485(4) ?(3), Z = 8, R = 0.063], electrochemically, and magnetically. Ligand-based redox couples are observed in electrochemical experiments that consist of reversible or quasireversible Cat/SQ steps at negative potentials and irreversible SQ/BQ oxidations at positive potentials. Magnetic measurements show temperature dependence that arises from antiferromagnetic exchange. Data have been fit to an expression that includes the effects of both Fe-SQ and SQ-SQ exchange with the result that J(SQ-SQ) is larger in magnitude than J(Fe-SQ). In methanol, the complex undergoes solvolysis to form [Fe(3,6-DBSQ)(2)(&mgr;-OMe)](2). Structural characterization [triclinic, P&onemacr;, a = 11.441(2) ?, b = 11.514(2) ?, c = 14.552(2) ?, alpha = 67.86(1) degrees, beta = 70.51(1) degrees, gamma = 72.79(1) degrees, V = 1641.8(5) ?(3), Z = 1, R = 0.048] has shown that the molecule is a centrosymmetric dimer with no close intermolecular contacts. The temperature dependence of magnetic measurements has been fit to a model consisting of two interacting S = (3)/(2) centers that arise from strong Fe-SQ exchange with J(Fe-Fe) = -22.4 cm(-1).     

ESR investigation of the substitution reactions in rhodium(I) complexes with spin-labeled ligands

A number of new spin-labelled Rh^I complexes containing both the 3,6-ditert-butyl-o-benzosemiquinone (3,6-SQ) fragment and n- and π-donor ligands have been prepared. The tetracoordinate derivatives of the composition L₂Rh-(3,6-SQ), where L  CO, P(OPh)₃, L  1/2 1,5-COD and the pentacoordinate complex (PPh₃)₂Rh(3,6-SQ)(CO) were isolated in individual state, the formation of other rhodium compounds was registered by ESR spectroscopy. The presence of an o-benzosemiquinolate ligand in the molecule with the unpaired electron located essentially on this fragment does not significantly influence on the reactivity of the metal ion in most cases; the n- and π-donor ligands exchange reactions studied by ESR confirm this fact. (PPh₃)₂Rh(3,6-SQ) has an abnormal distribution of spin density of the unpaired electron in the molecule, mostly located on the metal atom, this derivative bearing a close analogy to the rhodium(II) (d⁷) complexes.     

Crystal Structure and Characterization of a Double‐helical‐chain Coordination Polymer Zinc Complex Constructed by Flexible Dicarboxylate Ligand 2‐Nitro‐benzene‐1,4‐di(oxyacetate) and Rigid 2,2′‐Bipyridine Ligand

A novel double‐helical‐chain coordination polymer [Zn(nbdoa)(2,2′‐bipy)(H₂O)]_n constructed by flexible 2‐nitro‐benzene‐1,4‐di(oxyacetate) ligand and rigid 2,2′‐bipyridine ligand was obtained by hydrothermal reaction. The crystal structure demonstrates that there is a double‐helical chain with an inner channel running parallel to the helix axis without any interpenetration, which is connected to network via π‐π stacking and hydrogen bond interactions. The thermal analysis shows that the infinite helical structure is stable up to 536 K. The luminescence property is investigated and the complex shows photoluminescence in the solid state at room temperature.     

Fluorides and fluoro acids. XIII. The crystal structure of phosphorus pentafluoride

The solid state structure of phosphorus pentafluoride was determined from single-crystal MoKα diffractometer data. The crystal system is hexagonal, the space group P6₃/mmc, and Z = 2. At 109 K the lattice constants are a = 5.563(4) and c = 6.176(5) Å. The molecules have the maximum possible point symmetrie 6 m2 (D_3h) of a trigonal bipyramid. The axial bonds at 1.580(2) Å are significantly longer than the equatorial ones at 1.522(1) Å. Intermolecular interactions are very weak. The crystal structure is isotypic with that of the high-temperature form of SbCl₅.     

A New Zinc(II) Coordination Polymer with a Threefold‐Interpenetrating Diamondoid Net: Synthesis,Crystal Structure and Luminescent Property

The three‐dimensional (3D) coordination polymer, [Zn(dpa)(bib)]_n ( 1 ) [H₂dap = diaphonic acid and bib = 1,4‐bis(imidazol‐1‐yl)benzene], was prepared by hydrothermal synthesis and characterized by single‐crystal X‐ray diffraction, FT‐IR spectroscopy, XRPD, and elemental analysis. Crystal structure determination revealed that complex 1 shows a threefold diamond topological net. Furthermore, the solid‐state luminescent property of [Zn(dpa)(bib)]_n was investigated.     

Crystal and electronic structure of a hexacarbonyldiiron cluster tethered to naphthalene‐2‐thiolate ligands

The structure of the previously reported complex bis(μ‐naphthalene‐2‐thiolato‐κ²S:S)bis(tricarbonyliron)(Fe—Fe), [Fe₂(C₁₀H₇S)₂(CO)₆], has been characterized by X‐ray diffraction. In the solid state, the dinuclear complex adopts a butterfly‐like shape, with an equatorial–axial spatial orientation of the naphthalene groups covalently coupled to the [S₂Fe₂(CO)₆] unit. The asymmetric unit contains three independent [(μ‐naphthalene‐2‐thiolato)₂Fe₂(CO)₆] molecules. These molecules show intermolecular π–π stacking interactions between the naphthalene rings, which was confirmed by Hirshfield surface analysis. The electronic spectrum of the complex recorded in acetonitrile shows a band centered at 350 nm (ϵ = 4.6 × 10³ M⁻¹ cm⁻¹) and tailing into the visible region. This absorption can be attributed to a π→π* electronic transition within the naphthalene moiety and a metal‐based d→d transition.     

Crystal growth,characterization and photoluminescence study of a novel one dimensional coordination polymer of Cd(II) with thiophene-2,5-dicarboxylic acid

A novel one dimensional coordination polymer of Cd(II) with thiophene-2,5-dicarboxylic acid (H₂tdc), {[Cd(tdc) (H₂O)₃]·1.5H₂O}_n has been prepared by gel diffusion method. Elemental analysis, single crystal and powder X-ray diffraction studies, FT-IR and UV–visible spectral studies were used to characterize the title compound. Cd-thiophene units form a linear chain in the crystal structure. Thiophene rings of a linear chain are stacked parallel to each other while the thiophene rings of the adjacent chains are intercalated and stacked ant-parallel to each other. Extensive hydrogen bond formation and π-π interactions between thiophene moieties are responsible for the supramolecular architecture. TG/DTG studies confirm the presence of both lattice and coordinated water molecules. Photoluminescence studies showed that the title compound is red shifted by 46 nm compared to ligand.