Nickel(II) thiolates derived from transmetallation reaction of [Zn(Tab)4](PF6)2 with Ni(II) ions and their catalytic activity toward the CN coupling reactions

Reactions of NiCl₂·6H₂O or Ni(ClO₄)₂·6H₂O with 2,2′-bipyridine (2,2′-bipy), or 2-bis(diphenylphosphino)ethane (dppe) or 1,4-bis(diphenylphosphino)butane (dppb) followed by addition of [Zn(Tab)₄](PF₆)₂ (1) resulted in the formation of one trinuclear cationic complex [(2,2′-bipy)₄Ni₃(μ-Tab)₄]Cl_0.5(PF₆)_5.5 (2), one mononuclear cationic complex [Ni(Tab)₂(dppe)](PF₆)₂ (3), and one dinuclear cationic complex [Ni₂(dppb)(μ-Tab)₂(Tab)₂](PF₆)₂(ClO₄)₂ (4). Complexes 2–4 were characterized by elemental analysis, IR, UV–vis, ¹H and ³¹P NMR, and single-crystal X-ray diffraction. In the [(2,2′-bipy)₄Ni₃(μ-Tab)₄]^6 + hexacation of 2, the central Ni(II) atom is connected to two [Ni(2,2′-bipy)₂]^2 + fragments by two pairs of μ-Tab ligands, forming a linear trinuclear cationic structure. The Ni(II) center of the dication of 3 is tetrahedrally coordinated by two S atoms from two Tab ligands and two P atoms of one dppe ligand. Complex 4 has a dimeric cationic structure in which two [(Tab)Ni]^2 + species are linked by a pair of μ-Tab ligands and one dppb ligand. Complexes 2–4 displayed high catalytic activity toward the cross-coupling reactions of arylboronic acids and amines to produce N-arylated amines.     

Effect of Coordination Modes of HL Ligand on the Molecular Architecture of Its Transition Metal Complexes (HL = 5-Methyl-2-Phenyl-4-[(2-<Emphasis Type="Italic">o</Emphasis>-Tolylamino)-Phenylmethylene]pyrazol-3(2H)-one)

Abstract  Two Ag⁺ complexes [Ag(HL)₂(PF₆)] (1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2) (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) were synthesized and structurally characterized by EA analysis, IR spectra and X-ray crystallography. The result shows that two expected coordination modes (Modes I and III in Scheme 1) of the HL ligand, can be observed in its Ag⁺ complexes, while not in other transition metal ions (Ni²⁺, Co²⁺ or Cu²⁺) complexes whether deprotonation or not for the HL ligand. Graphical Abstract  Three possible coordination modes (Modes I, II or III in Scheme 1) of the selected HL (HL = 5-methyl-2-phenyl-4-[(2-o-tolylamino)-phenylmethylene]pyrazol-3(2H)-one) ligand, can be adopted, in which Modes I and III can be observed in its two Ag⁺ complexes [Ag(HL)₂(PF₆)](1) and [(AgL) _n  · n(CH₂Cl₂) · n(0.5H₂O)] (2), while Mode II just observed in its transition metal ions (Cu²⁺, Ni²⁺, or Co²⁺) complexes, resulting from the deprotonatd form of the HL ligand and the coordination characters of transition metal ions.      

The Beauty and Complexity of the Mixed-Ligand Pd(II)-containing Monomers,Oligomers and Polymers Built upon Diphosphines and 1,8-Diisocyano-<Emphasis Type="Italic">p</Emphasis>-menthane

The starting materials Pd(diphos)Cl₂ where diphos = bis(diphenylphosphino)ethane (dppe), bis(diphenylphosphino)propane (dppp), bis(diphenylphosphino)butane (dppb), and Pd₂(diphos′)₂Cl₄ where diphos′ = bis(diphenylphosphino)pentane (dpppen) and bis(diphenylphosphino)hexane (dpph) were reacted with the bridging ligand 1,8-diisocyano-p-menthane (dmb) to form species of the type {Pd₂(diphos)₂(dmb) ₂ ⁴⁺ } _n and {Pd(diphos′)₂(dmb) ₂ ⁴⁺ } _n . Except for Pd₂(dppe)₂(dmb) ₂ ⁴⁺ , which was characterized by X-ray crystallography, the identity of the other weakly soluble dmb-containing materials were exhaustively characterized in solution and in the solid state by ³¹P NMR (Magic Angle Spinning), chemical analyses, MALDI-TOF, DSC, TGA, IR and T ₁/NOE (³¹P NMR spin-lattice relaxation time and nuclear overhauser enhancement constant measurements). Model compounds such as Pd(diphos)(CN-tBu) ₂ ²⁺ (diphos = dppe, dppp, dppb) and Pd₂(diphos′)₂(CN-tBu) ₄ ⁴⁺ (diphos′ = dpppen, dpph; as BF ₄ ⁻ or PF ₆ ⁻ salts), were prepared and also characterized by X-ray crystallography. Evidence for mono- (model complexes only of the type dppe, dppp, and dppb) and dinuclear complexes, as well as oligomers and polymers, are obtained for most cases, as well as the presence of monomer–oligomer (or polymer) equilibrium. During the course of this study, the complexes [Pd(dppp)(CN-tBu)₂](TCNQ)(Cl), [Pd₂(dpppen)₂(CN-tBu)₂(Cl)₂](PF₆)₂, and [Pd₂(dpppen)₂(CN-tBu)₂(CN)₂](TCNQ)₂ (TCNQ⁻ = tetraquinodimethane anion) were isolated and characterized by X-ray crystallography.This paper is dedicated to Professor Richard J. Puddephatt.     

Synthesis, Structure and Cyclic Voltammetry Studies of a 2D Sheet-like μ3-Hydroxyl- and μ2-, μ4-Oxamidato-Bridged Copper(II) Complex

A novel 2D sheet-like copper(II) complex formulated [Cu₆(trans-oxen)₃(μ₃-OH)₂(H₂O)₂]_n-(ClO₄)_4n^.2nH₂O (1), where H₂oxen is N,N’-bis(2-aminoethyl)oxamide, has been synthesized and characterized by elemental analysis, IR and UV–visible spectroscopy, and single-crystal X-ray diffraction. 1 crystallizes in triclinic space group P-1 with crystallographic data: a = 10.299(2) ?, b = 10.833(2) ?, c = 11.781(2) ?, α = 69.95(3)°, β = 81.10(3)°, γ = 62.44(3)°, and Z = 2. In the crystal structure, the cation [Cu₆(trans-oxen)₃(μ₃-OH)₂(H₂O)₂]_n⁴ⁿ⁺ exhibits a two-dimensional sheet-like structure for Cu(II) ions bridged both by trans-oxen and hydroxyl groups. Each Cu(II) ion is located in a slightly distorted square-pyramidal environment. The hydroxyl group bridges three [Cu(oxen)Cu]²⁺ dications in which one oxen²⁻ is μ₂-bridge while the other two act as never before reported μ₄-bridge. Perchlorate anions and H₂O molecules are inserted between the sheets and bridge the 2D cations via N–H···O and O–H···O hydrogen bonds to form an infinite three-dimensional system. The cyclic voltammetric behavior of 1 and the influence of counter ions on structure are preliminarily investigated.     

A Novel Bimetallic Chain Based on [Mo(CN)<Subscript>8</Subscript>]<Superscript>3−</Superscript> and Yb<Superscript>3+</Superscript> Ions as Building Blocks in Which Containing Many Intriguing Structural Features

A novel Mo^V–Yb^III bimetallic chain, {[Yb^III(bpy)₂(DMF)(H₂O)][Mo^V(CN)₈]·0.5bpy·4.5H₂O}_n (1) (DMF = N,N′-dimethylformamide; bpy = 2,2′-bipyridine), has been constructed by the reaction of [Mo(CN)₈]³⁻ with Yb³⁺ and 2,2′-bipyridine. Complex 1 is confirmed as a host–guest supramolecular structure by X-ray structural analysis. The neighboring chains interact with each other with two types of hydrogen bonds and two types of π···π interactions. Thus complex 1 has a unique 3D network. Magnetic analysis of 1 indicates the presence of a strong Yb^III single-ion effect owing to spin–orbital coupling within this system.     

A New Metal–Organic ZnII Supramolecular Assembled via Hydrogen Bonds and N···N Interactions as a New Precursor for Preparation Zinc(II) Oxide Nanoparticles, Thermal, Spectroscopic and Structural Studies

A new 1D supramolecular involving two different ligands, {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O (GB = 2-guanidinobenzimidazole and bpe = 1,2-bis(4-pyridyl)ethylene, has been synthesised, characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR spectroscopy. The thermal stability of compound {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O was studied by thermal gravimetric and differential thermal analyses. The single crystal X-ray analysis shows that the complex is a one-dimensional polymer involving macrocycle rings as a result of non-covalent bridging bpe ligands via N–H···N and N···N interactions, N–H···bpe···bpe···H–N, with the basic repeating {[Zn(GB)₂](μ-bpe)₃}(ClO₄)₂·H₂O units and by connecting [Zn(GB)₂]²⁺ nodes. ZnO nanoparticles were obtained by calcination of compound {[Zn(GB)₂]·(μ-bpe)₃} _n (ClO₄)_2n ·nH₂O at 500 °C in air. The nanoparticles were characterized by X-ray diffraction and scanning electron microscopy.     

Hydrothermal Synthesis and Crystal Structures of Cd(II)-Based 1D Coordination Polymer and Mn(II) Coordination Complex with Mixed N- and O-donor Ligands: [Cd2(4-4′-bpy)2(pa)4]n·0.25(H2O) and [Mn(4-4′-bpy)2(pa)(H2O)3]ClO4·2(H2O)

Two new complexes, [Cd₂(4-4′-bpy)₂(pa)₄] _n ·0.25H₂O (1) (pa = phenylacetate), and [Mn(4-4′-bpy)₂(pa)(H₂O)₃]ClO₄·2H₂O, (2), have been obtained from hydrothermal reaction of Cd(NO₃)₂·4H₂O and Mn(ClO₄)₂·6H₂O with a mixture of the ligands, 2-phenylmalonic acid (2-phmalH₂) and 4-4′-bipyridine (4-4′-bpy). The pa is formed in situ by decarboxylation of phenylmalonic acid. These complexes have been characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis and single-crystal X-Ray diffraction. The Cd(II) center is seven-coordinate and linked via pa ligands to form a binuclear complex in the asymmetric unit of 1. A ladder-like 1D chain of binuclear units is formed by Cd(II)–N coordination bond through 4-4′-bpy ligands. Complex 2 consists of a mononuclear manganese center based on a distorted octahedral geometry and exhibits a supramolecular structure containing hydrogen bonds and extensive π···π and C–H···π interactions.     

Lithium-metal potential in Li<Superscript>+</Superscript> containing ionic liquids

Impedance spectroscopy studies of the interface between lithium and ionic liquid (IL) showed the formation of a film (solid electrolyte interface, SEI), protecting metal from its further dissolution. Consequently, the potential of metallic lithium immersed in an electrolyte containing Li⁺ cations may be described as a Li|SEI|Li⁺ system, rather than simply Li/Li⁺. The potential of lithium-metal in a series of ionic liquids (and in a number of molecular liquids) containing Li⁺ cation (0.1 M) was measured versus the Ag|(Ag⁺ 0.01 M, cryptand 222 0.1 M, in acetonitrile) reference. The lithium-metal potential (E(Li|SEI|Li⁺)) was ca. −2.633 ± 0.017 V in ILs based on the [N(CF₃SO₂)₂ ^– ] anion, while −2.848 ± 0.043 V in ILs containing [BF₄ ^– ] anion (the difference is ca. 200 mV). In the case of ILs based on the triflate anion ([CF₃SO₃ ^– ]), the cation of ionic liquid also influences the E(Li|SEI|Li⁺) value: it was ca. −1.987 ± 0.075 V for imidazolium based cations and much lower (−2.855 V) for the pyrrolidinium based cation. In ionic liquid based on the imidazolium cation and hexafluorophosphate anion ([PF₆ ^– ]), the Li/SEI/Li⁺ potential was −2.245 V. The Li|SEI|Li⁺ potential measured in cyclic carbonates was −2.780 ± 0.069 V while in dimethylsulfoxide showed the lowest value of ca. −3.285 V. The measured potentials were also expressed versus the formal potential of the ferrocene/ferrocinium redox couple, obtained from cyclic voltammetry.     

Hydrothermal Synthesis of Metal–Organic Coordination Polymers Constructed from Asymmetric Semi-rigid V-shaped Dicarboxylate and Nitrogen-Contained Mixed Ligands

Three new coordination polymers, [Ni(2,4′-oba)(1,10-phen)] _n (1), {[Ni (2,4′-Hoba)₂(4,4′-bipy)(H₂O)₂]·2H₂O} _n (2) and [Zn(2,4′-oba) (4,4′-bipy)] _n (3) (2,4′-H₂oba = 2-(4-carboxyphenoxy)benzoic acid, 1,10- phen = 1,10-phenanthroline, and 4,4′-bipy = 4,4′-bipyridine) have been obtained by hydrothermal synthesis. The framework structures of these polymeric complexes have been determined by single-crystal X-ray diffraction studies. Complex 1 exhibits double-helical chains formed by π–π stacking interactions from the phenyl rings of the 1,10-phen ligands. Complex 2 forms a two-dimensional supramolecular architecture directed by hydrogen bonding. Complex 3 exhibits a three-dimensional structure; Schl?fli symbol of {4⁴·6¹⁰·8}. The luminescent property of compound 3 is discussed.     

A New Nitrosyl-bridged Bimetallic Nitroprusside Complex: Synthesis,Crystal Structure,Supramolecular Self-assembly and Spectral Behavior of Interactions with DNA

A new nitrosyl-bridged bimetallic nitroprusside complex, [Ba(phen)₃(H₂O)][Fe(CN)₅NO]·1.5phen·2H₂O (phen = 1,10-phenanthroline) (1), has been synthesized and characterized by elemental analysis and single crystal X-ray diffraction. The crystal structure analysis reveals that complex 1 crystallizes in the triclinic space group Pī. The asymmetric structural unit is comprised of one [Ba(phen)₃(H₂O)]²⁺ complex cation, one [Fe(CN)₅NO]^2– complex anion, 1.5-uncoordinated phenanthroline molecules and two lattice water molecules. The complex ions are linked into a 1D chain-like arrangement by the trans CN and NO groups in nitroprusside. The six-coordinated Fe-atom forms a distorted octahedral coordination configuration, and the Ba-atom has a nine-coordinate monocapped antiprismatic geometry. Five types of π–π stacking interactions of phenanthroline and some intra- and intermolecular hydrogen bonds are observed in the 3D supramolecular self-assembly. Absorption spectroscopy, fluorescence titration and viscometry studies of the interaction between complex 1 and calf thymus DNA indicate that complex 1 is a moderate metallo-intercalator with the intrinsic binding constant of 3.70 × 10⁴ M⁻¹ and the linear Stern–Volmer quenching constant of 5.98 × 10⁴ M⁻¹.     

Zinc(II) Metal–Organic Framework with Nano-Sized Channels Based on Paddle-Wheel Units

A Zn(II) metal–organic framework with nano-sized channels from 4,4′-bipyridine (4,4′-bipy) and 4′-sulfo-biphenyl-4-carboxylate (sbpc²⁻) ligands, {[Zn(μ-4,4′-bipy)_1.5(μ-sbpc)]·5H₂O} _n (1), has been synthesized by the hydrothermal method. Compound 1 was characterized by X-ray powder diffraction, IR spectroscopy, elemental analysis and single-crystal X-ray crystallography. The structural studies show the Zn atoms have a six-coordinate geometry with a distorted octahedral environment constructed of paddle-wheel [Zn₂(OOC)₄] building units with 4,4′-bipy and sbpc²⁻ linkers stacked over each other to generate three-dimensional nano-sized channels occupied by guest H₂O molecules.     

Synthesis, Supramolecular Architecture and DNA Binding Studies of a Novel Heterotrinuclear FeIII/CoII/FeIII Complex: [Co(phen)2][Fe(phen)(CN)4]2·4H2O (phen?=?1,10-phenanthroline)

A novel cyano-bridged heterotrinuclear Fe^III/Co^II/Fe^III complex, [Co(phen)₂][Fe(phen)(CN)₄]₂·4H₂O (1) (phen = 1,10-phenanthroline), has been synthesized under solvothermal conditions, and characterized by elemental analysis, FI-IR spectrum and single-crystal X-ray diffraction. The structure analysis reveals complex 1 is constructed into a 3D supramolecular architecture through abundant intermolecular non-covalent interactions. According to the supramolecular self-assembly of complex 1, five types of π–π stacking models of phenanthroline ligands, hydrogen bonds formed by four lattice water molecules, and C–H···N weak interactions involving cyano groups are all observed. Electronic absorption spectroscopy and fluorescence titration studies of the interaction between complex 1 and calf thymus DNA are suggestive of an intercalative binding mode with an intrinsic binding constant of 7.95 × 10³ M⁻¹ and a linear Stern–Volmer quenching constant of 1.033 × 10⁵ M⁻¹.     

Supramolecular Framework Based on Pyridiniodiketone Ligand via Non-classic Hydrogen Bonding

A novel ligand L, 4-(1-hydroxy-3-oxo-3-phenylpropenyl)-1-methylpyridinium was synthesized and identified by NMR spectra and X-ray single crystal structure analysis from L · CH₃SO₄ (1L). Through self-assembling reactions, two new Cu^II/La^III-organic complexes, [CuL₂(SCN)][SCN] · H₂O (2Cu) and [LaL₂(SO₄)Cl₂] · (toluene) (3La), have been synthesized and characterized by X-ray crystallography. Structural analysis of 1L revealed that L and HSO₄ ⁻ coexist in a unit cell. For 2Cu, Cu(II) ion show a five-coordinated structure with a highly compressed square pyramid configuration; For 3La, each La(III) ion has an eight-coordinated structure with a distorted capped pentagonal bipyramidal geometry. It should be mentioned that supramolecular framework was formed via a number of hydrogen bonding interactions. Here, intramolecular C–H···O hydrogen bonding interactions stabilized and restricted the distortion between different rings. On the contrary, intermolecular hydrogen bond, e.g. C–H···O dual hydrogen bond interactions (1L), O5-involving triple C–H···O/O–H···O(N) hydrogen bond (2Cu) and triple C–H···Cl hydrogen bonding(3La), greatly affect geometric distortion between rings from ligand. Finally, we believe that the cooperative effect plays more important roles in supramolecular self-assembly.     

A New 2D Cd(II) Grid-like Structure Based on Hetero-Chiral Helical Chains: Synthesis, Crystal Structure, Thermal and Luminescent Properties

A new 2D Cd(II) coordination polymer, [Cd(BBI)₄Cl₂] _n (BBI = 1,1′-(1,4-butanediyl)bis (imidazole)) (1), was synthesized under hydrothermal conditions, and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction crystallography. For complex 1, each Cd(II) ion crystallizes in a [CdN₄Cl₂] six-coordinated slightly distorted octahedral geometry, coordinating to four BBI ligands by Cd–N bonds, completed by two terminal Cl⁻ anions. The characteristic of 2D grid-like layers, from the central Cd(II) ions as knots and BBI ligands as spacers, is the hetero-chiral helical chains of left- and right-hand helixes. Two kinds of π interactions assemble 2D layers into 3D supramolecular architecture in an ···ABC··· packing arrangement. The fluorescent properties were studied in the solid state for its luminescent applications.     

Solvent Control Over Structural Diversity of Two Copper (II) Complexes Based on Polyaromatic Acid Ligand

Abstract  

A new bipod polyaromatic acid ligand H₂bcm (H₂bcm = {2, 4-bis [(2′-carboxyphenoxy) methyl]-1,3,5-trimethylbenzene}) is prepared and its two novel binuclear coordination compounds, [Cu₂(bcm)₂(CH₃OH)₂]·2CH₃OH (1) and [Cu₂(bcm)₂(CH₃CH₂OH)₂]·2CH₃CH₂OH (2), have been synthesized with copper acetate and H₂bcm ligand in methanol solvent and ethanol solvent respectively, and characterized by the element analysis, IR, TGA and single crystal X-ray diffraction. The results of structural analysis indicate that 1 crystallizes in the triclinic system with space group P1, while 2 crystallizes in the monoclinic system with space group P2₁ /c. Furthermore, 1 adopts μ ₂ -COO⁻ and syn–syn coordination mode with Cu (II)···Cu (II) separation of 2.5868(11) ? and forms 1D zigzag chain structure by O···O interactions. The coordination of 2 is similar to that of 1 except that ethanol molecules are coordinated instead of methanol molecules with Cu (II)···Cu (II) separation of 2.5973(13) ?. Two-dimensional network structures of 1 and 2 are formed through π–π interactions.     

Catalytic, Luminescence Activities and Structure of Metal-Organic Frameworks Containing CuCN Building Blocks and Bipodal Bridging Ligands

The reactions of K₃[Cu(CN)₄], R₃SnCl and bipodal ligands, where R = (n-Bu)₃SnCl and L = quinoxaline (qox) and R = Me₃SnCl and L = quinazoline (qaz) afford the red needle crystals of _￥³ [ \textCu₂ ( \textCN )₂ m\text-(qox) ]₂ {}_{\infty }^{3} \left[ {{\text{Cu}}_{2} \left( {\text{CN}} \right)_{2} \mu {\text{-(qox)}}} \right]_{2} , 1 and the orange needle crystals of [Cu₂(CN)₂μ(qaz)]_n, 2. 1 was subjected to single crystals X-ray study while 2 was investigated by IR, ¹H NMR and mass spectra as well as TGA. The crystal structure of 1 exhibits puckered CuCN chains connected by qox molecules forming 2D-sheets. The 2D-sheets contain hexagonal nets stacked in A···A···A fashion. The paralleled sheets are close packed via extensive H-bonds, π–π stacking, strong Cu-Cu interaction and short Cu–C contacts which develop 3D-network. Unique rhombic [Cu₂(μ₃-CN)₂] motifs result as consequence of interwoven of the 2D-sheets. The structure of 2 exhibits different XRPD pattern than that of 1 although, the two structures have the same Cu:CN:L stoichiometric ratio. The emission spectra of 1 and 2 display bands around 390, 420 and 475 nm corresponding to MC transition, ¹(n,π*) → S_o and MLCT, respectively. Thus, 1 and 2 can be considered as examples of room-temperature luminescent Cu-containing polymers which can be used in applications as molecular sensing systems. Also, the oxidative degradation of Metanil Yellow (MY) dye has been investigated by hydrogen peroxide catalyzed by 1 or 2. The catalytic activity of 1 is more pronounced than that of 2.     

One-Dimensional Cd(II) and Co(II) Coordination Polymers with Dinuclear Secondary Building Units Constructed by 1,1′-Biphenyl-3,3′-Dicarboxylic Acid: Synthesis, Structures, Luminescent and Magnetic Properties

Bilayered diffusion and hydrothermal synthetic methods using pyridine (py) and 2,6-dimethylpyrazine (dmpz) as weak bases and small terminal ligands generated two Cd(II) and Co(II) 1D coordination polymers with dinuclear metal clusters as secondary building units (SBUs) from an organic bridging ligand, 1,1′-biphenyl-3,3′-dicarboxylic acid (H₂ L). They are {[Cd₂(L)₂(py)₄] (py)(CH₃OH)} _n (1) and [Co₂(L)₂(dmpz)₄(H₂O)] _n (2). Compounds 1 crystallizes in the monoclinic space group P2(1)/c, while 2 crystallizes in the triclinic space group P-1. Especially, compound 2 possesses the 1D chain structure that contains two linked left-handed and right-handed helices. Fluorescent measurements for 1 display strong blue light emissions with the maximum emission at 396 nm with the excitation of 320 nm. Magnetization study shows the existence of weak antiferromagnetic coupling for 1 with the negative −E ₂/k value of −1.3 K.     

Syntheses and Characterizations of Three Cu(II) Complexes with 2,2′-Bipyridine-3,3′-dicarboxylate and <Emphasis Type="Italic">N</Emphasis>-Donor Ancillary Ligands

Abstract  

Three novel inorganic–organic hybrid frameworks of [Cu(BPDC)(2,2′-bipy)] (1), [Cu(BPDC)(BIB)₂ ·H₂O]_n (2) and [Cu(BPDC)(4,4′-bipy)]_n (3) (BPDC²⁻ = 2,2′-bipyridine-3,3′-dicarboxylate; 2,2′-bipy = 2,2′-bipyridine; BIB = 1,2-bis(imidazol-1-ylmethyl)benzene; 4,4′-bipy = 4,4′-bipyridine) were prepared. The three complexes have been characterized by the elemental analyses, IR spectra, TGA and the single crystal X-ray diffraction. Two intramolecular Cu(II) centers of 1 are encircled by two BPDC²⁻ ligands forming an 18-membered ring, which is further assembled into a three-dimensional (3D) supramolecular architecture through the C–H···O hydrogen-bonding interactions. Complex 2 possesses a two-dimensional layer network, while complex 3 is a three-dimensional polymer composed of Cu-BPDC helical chains bridged by 4,4′-bipy. In addition, the electrochemistry of complex 1 was investigated.     

Growth and Magneto-Optical Properties of Li2MoO4·1.8Tb2(MoO4)3 Crystal

Li₂MoO₄·1.8Tb₂(MoO₄)₃ crystal, a kind of solid solution crystal, was grown in air by the top seeded solvent growth method in a Li₂Mo₂O₇ flux. The lattice parameters of the crystal were determined by X-ray diffraction analysis. The absorption coefficient of the crystal was investigated at wavelengths from 400 to 1500 nm at room temperature. Valence states of Tb ions in Li₂MoO₄·1.8Tb₂(MoO₄)₃ crystal were analyzed by X-ray photoelectron spectroscopy measurement. Verdet constants for the Li₂MoO₄·1.8Tb₂(MoO₄)₃ crystal at 532, 633 and 1064 nm wavelengths were measured by the extinction method. They are −341, −239 and −75 rad m⁻¹ T⁻¹, respectively. The results show that the crystal has a larger magneto-optical figure of merit than terbium gallium garnet at wavelength of 633 nm.     

One-Dimensional Cobalt(II) and Zinc(II) Succinato Coordination Polymers with Nicotinamide: Synthesis, Structural, Spectroscopic, Fluorescent and Thermal Properties

Cobalt(II) and zinc(II) succinato (suc) coordination polymers with nicotinamide (nia), {[Co(μ-suc)(H₂O)₂(nia)₂] · 2H₂O} _n (1) and {[Zn(μ-suc)(H₂O)₂(nia)₂] · 2H₂O} _n (2) have been synthesized and characterized by elemental analyses, magnetic moments, IR and TG-DTA. Single-crystal X-ray analyses of 1 and 2 reveal that these complexes are isostructural and crystallize in triclinic space group Complexes 1 and 2 are 1-D coordination polymers, in which the metal(II) ions exhibit an octahedral geometry with two suc, two nia and two aqua ligands. The nia ligand is N-bonded, while the suc ligand bridges the metal centers through the carboxylate groups. The 1D chains are further assembled to form 3D networks by strong N–H···O and OW–H···O hydrogen bonds. IR spectra confirm the coordination modes of both suc and nia ligands, while TG-DTA data are in agreement with the crystal structures. Fluorescent analysis in the solid state shows that all complexes display intraligand (π–π*) emissions of nia.