Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

A novel stair-like lithium coordination polymer constructed from 4,4′-bipyridine

A novel stair-like lithium coordination polymer Li₂(4,4′-bpy)₂(NO₃)₂, 1, has been synthesized by using standard Schlenk techniques. X-ray diffraction shows the 2D stair-like framework contains an approximately perpendicular 1D “Z” type Li-4,4′-bpy chain and an unprecedented Li–NO₃ chain.     

Synthesis, crystal structure and photoelectric property of two novel coordinated complexes constructed by 4,4′-bipyridine and sebacic acid

Two two-dimensional (2D) new complexes: [M(bpy)(C₁₀H₁₆O₄)H₂O] [M = Ni (1), Co (2); bpy = 4,4-bipyridine, C₁₀H₁₈O₄ = sebacic acid] were synthesized by the hydrothermal reaction at 180 °C and characterized by elemental analysis, infrared spectra, and thermogravimetric spectra, single-crystal X-ray diffraction and surface photovoltage spectrum (SPS). The single-crystal X-ray diffraction showed that both complexes are isomorphous, crystallized in monoclinic system, and space group P2₁/c. In addition, The results of SPS for complexes (1) and (2) indicate that these two complexes exhibit positive surface photovoltage response in the range of 300–800 nm, which can be assigned to LMCT and d → d^* electronic transition. The SPS spectra of the two complexes are consistent with their UV–Vis spectra.     

A new (3,4,7)-connected topology framework based on [Cd2(CO2)3O4N2] second building unit

A new 3D coordination polymer [Cd₂(L³)(BTC)(H₂O)] (1) (HL³ = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, H₃BTC = 1,3,5-benzenetricarboxylic acid), has been isolated under hydrothermal condition and characterized by single-crystal X-ray diffraction. Compound 1 is constructed from Cd₂-based second building units (SBUs) [Cd₂(CO₂)₃O₄N₂] and displays a 3D (3,4,7)-connected net with (4²·6)(4³·6³)(4⁵·6¹¹·8⁵) topology. In addition, the photoluminescent spectra indicate compound 1 may be a good candidate for blue-luminescent materials.     

Design and construction of two new polymers featuring macrocyclic subunits based on a rigid clamp-like ligand

Reaction of a rigid conjugated clamp-like ligand N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide (bppdca) with ZnSO₄·7H₂O or CoSO₄·7H₂O resulted in the formation of two new polymers, namely, {[Zn₂(bppdca)(SO₄)₂(DMF)₂]·(DMF)}_n (1) and {[Co(bppdca)(SO₄)(CH₃OH)(DMF)]·H₂O}_n (2). Both 1 and 2 feature one-dimensional double-chain structures with macrocyclic subunits, and the chains further self-assemble into a higher-dimensional framework via the hydrogen-bonding and π–π stacking interactions. Fluorescence studies show that the free ligand displays a strong fluorescence emission in solid state at room temperature, but in 1 and 2, the complexation of the ligand with metal ions and weak intermolecular interactions make the fluorescence emission partial quenching.     

Anion-directed assembly of two novel cadmium(II) complexes constructed by 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) ligand

Depending on the different coordinated anions used, reaction of Cd(II) salt with 2,2′-(1,4-butanediyl)bis(1H-benzimidazole) results in the formation of two coordination polymers: a 1D chain {[Cd(H₂C4BIm)Cl₂] · (H₂C4BIm)}_n (1), and a 2D sheet [Cd(HC4BIm)(NCS)]_n (2) which features distorted 4.8² topology (H₂C4BIm = 2,2′-(1,4-butanediyl)bis(1H-benzimidazole)). The fluorescence properties for both the complexes have been studied.     

Syntheses and crystal structures of novel silver(I) coordination polymers based on linear or tetrahedral coordination environments

Two coordination polymers containing Ag(I) atoms, {[Ag(3-pia)](PF₆)}_n (1) and {[Ag(3-pia)₂](PF₆)}_n (2) (3-pia = N-pyridin-3-yl-isonicotinamide), have been synthesized using different solvents, and characterized by single X-ray analyses. In compound 1, Ag(I) atoms are linearly coordinated by two 3-pia ligands, resulting in one-dimensional chains. On the other hand, in compound 2, Ag(I) atoms are tetrahedrally coordinated by four 3-pia ligands, resulting in two-dimensional sheets.     

The chiral Zn(II)–Na(I) coordination polymer: Synthesis, crystal structure, thermal and optical properties

The chiral Zn(II)–Na(I) coordination polymer with formula [NaZn(acac)₂(AcO)(EtOH)] (1) has been synthesized, and characterized by ¹H NMR and FT-IR spectra, elemental, X-ray, and thermogravimetric analysis (TGA). X-ray crystallographic study revealed that 1 crystallizes in the non-centrosymmetric space groups P2₁2₁2₁ and exhibits a one-dimensional polymer chain. Linear optical properties were investigated by UV/Vis spectrophotometer techniques. Kurtz–Perry powder second-harmonic-generation (SHG) test confirms the non-linear optical (NLO) property of the grown crystal.     

A new di-μ-oxo bis[oxovanadium(V)] complex containing Schiff base ligand derived from 1,2-diaminopropane and 2′-hydroxy-4′-methoxyacetophenone: Synthesis, structure and catalytic properties

New dioxovanadium(V) complex bearing tridentate ligand of 1:1 condensation of 1,2-propylenediamine and 2′-hydroxy-4′-methoxyacetophenone has been synthesized and characterized by IR and ¹H NMR spectroscopy and elemental analysis. The single-crystal structure of the complex shows that each vanadium(V) ion is six-coordinate through three bonds to oxo groups and through bonds to the tridentate Schiff base ligand. The title complex is used as catalyst for the selective epoxidation of cyclooctene. The catalytic system described here is an efficient and inexpensive method for the oxidation of olefins, with the advantages of high activity, selectivity, and short reaction time.     

Preparation and properties of novel fluorinated polyimides based on 2,2′,6,6′-tetrafluorobenzidine

Fluorinated polyimides were prepared from 2,2′,6,6′-tetrafluorobenzidine and four conventional dianhydride monomers by a solution polycondensation reaction followed by a chemical imidization. Polyimide based on 2,2′,6,6′-tetrafluorobenzidine and hexafluoroisopropylidene bis(3,4-phthalic anhydride) (6FDA) is soluble in organic solvents such as NMP, DMA, DMF, THF, chloroform, and acetone while those based on 2,2′,6,6′-tetrafluorobenzidine and pyromellitic dianhydride (PMDA), benzophenone-3,3′,4,4′-tetracarboxylic acid dianhydride (BTDA), diphenylether-3,3′,4,4′-tetracarboxylic acid dianhydride (ETDA) are not. Polyimide from 2,2′,6,6′-tetrafluorobenzidine and 6FDA possesses high optical transparency at 350–700 nm and has a in-plane refractive index of 1.558 at 632.8 nm. All polyimides exhibit glass transition temperatures above 350°C. They also possess very high thermal stability. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1605–1609, 1998     

Hydrothermal synthesis and crystal structure of a novel cyanide-bridged double helical copper(I) coordination polymer [Cu3(CN)3(phen)]n

Hydrothermal reaction of CuCN, K₃[Fe(CN)₆] and 1,10-phenanthroline affords a novel cyanide-bridged copper(I) coordination polymer [Cu₃(CN)₃(phen)]_n (1). The complex displays an interesting one-dimensional neutral double helical framework with (phen)Cu–CN– side-arms as interchain bridges. The double helical chains are close packed in a parallel fashion, and the phen ligands stack in an interpenetrating mode, which leads to π–π interactions between parallel phen planes. The thermal stability and fluorescent property have also been investigated.     

Synthesis and properties of new aromatic polyimides based on 2,2′‐dibromo‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride

New polyimides with enhanced thermal stability and high solubility were synthesized in common organic solvents from a new dianhydride, 2,2′‐dibromo‐4,4′,5,5′‐benzophenone tetracarboxylic dianhydride (DBBTDA). DBBTDA was used as monomer to synthesize polyimides by using various aromatic diamines. The polymers were characterized by IR and NMR spectroscopy and elemental analysis. These polyimides had good inherent viscosities in N‐methyl‐2‐pyrrolidinone (NMP) and also high solubility and excellent thermo‐oxidative stability, with 5 % weight loss in the range 433 to 597 °C. Copyright © 2004 Society of Chemical Industry     

Syntheses and topological networks of two azide complexes based on 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole ligands

Two new azide complexes, [Cd₂(3-abpt)(N₃)₄]_n (1) and [Cu(3-abpt)₂(N₃)₂] (2) (3-abpt = 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole), have been prepared and structurally characterized. Complex 1 displays an interesting 2D polymeric structure with rarely reported 3,7-connected (3²;4)(3⁴;4⁶;5⁶;6⁵) network in the Schafli notation. Complex 2 contains mononuclear pieces, and they are linked each other through weak CuN coordination bonds to form a 2D sheet with (4, 4) topology. The thermal stability and fluorescent property of 1 have also been investigated.     

Synthesis and characterization of a novel liquid crystalline star‐shaped polymer based on α‐CD core via ATRP

Well‐defined side‐chain liquid crystalline star‐shaped polymers were synthesized with a combination of the “core‐first” method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the α‐Cyclodextrins (α‐CD) bearing functional bromide groups was synthesized, confirmed by ¹H‐NMR, MALDI‐TOF, and FTIR analysis. Secondly, the side‐chain liquid crystalline arms poly[6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with ¹H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer α‐CD‐PMMAzo_n was similar to that of the linear homopolymer. The phase‐transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star‐shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The preparation and properties of segmented‐chain liquid crystalline polyesters based on 4,4′‐dihydroxybiphenyl by interfacial polycondensation

Thermotropic homopolyesters were prepared through interfacial polycondensation of 4,4′‐dihydroxybiphenyl with sebacoyl chloride. The optimal conditions of the process, in terms of the best yield, were studied through investigating the type of organic phase, amount of phase transfer agent, time and temperature of reaction, and volume ratio of aqueous to organic phase. The structure of the sample that had the best yield (53.235% ± 5%) was determined by means of elemental analysis, infrared spectra, and X‐ray. The effect of the molar ratio of the monomers on the yield and inherent viscosity was investigated. The inherent viscosity of the samples varied between 0.095 and 0.25 dL/g. The mesophase formed at elevated temperatures was studied by differential scanning calorimetry, polarized light microscopy, and depolarizing transmittance measurements. Our observations revealed that poly(4, 4′‐diphenyl sebacate), in contrast to previous reports that suggest this polymer is smectgenic, could produce nematic phase. It could be concluded that the chemical structure ordering of the poly(4, 4′‐diphenyl sebacate) plays a significant role in its liquid crystalline behavior. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1594–1606, 2005     

Synthesis, crystal structure and electrochemical properties of a novel tetranuclear silver(I) cluster based on 1,1′-bis[(2-hydroxybenzylidene)thiocarbonohydrazono-1-ethyl] ferrocene (FcL)

A novel tetranuclear silver(I) heterocyclic cluster, which is of nano-hole structure, based on 1,1′-bis[(2-hydroxybenzylidene)thiocarbonohydrazono-1-ethyl] ferrocene (FcL) has been prepared and structurally characterized by single-crystal X-ray diffractions. In addition, its electrochemical properties are also discussed. The results confirm that the receptor FcL is responsive to Ag⁺.     

Synthesis, structure and magnetism of a μ3-carbonato bridged nickel(II) complex with 2,2′,2″-tris(2-aminoethyl)amine ligand: a new coordination mode of carbonato bridge

A novel bridged Ni(II) complex with tris(2-aminoethyl)amine (tren), [Ni₃(tren)₃(H₂O)₂(μ₃-CO₃)](ClO₄)₄ · 2H₂O, was obtained by bubbling CO₂ into an aqueous solution of μ₂-OH bridged Ni(II) complex. The X-ray structure analysis of the title complex shows that the three nickel atoms are asymmetrically bridged by one tetradentate carbonato ligand, which presents a new bridge mode. The further magnetochemistry study exhibits a strong antiferromagnetic coupling between nickel(II) ions with J₁ = −11.03 cm⁻¹, J₂ = −80.27 cm⁻¹ in the title compound.     

Synthesis and Characterization of 1,5‐Dinitro‐2,6‐bis(trinitromethyl)‐3a,4a,7a,8a‐tetrahydro‐[1,4]dioxino[2,3‐d:5,6‐d′]diimidazole (DNTNDI)

The polynitro imidazole derivative 1,5‐dinitro‐2,6‐bis(trinitromethyl)‐3a,4a,7a,8a‐tetrahydro‐[1,4]dioxino[2,3‐d:5,6‐d′]diimidazole (DNTNDI) was synthesized through nitration of 2‐(dinitromethylene)‐1H‐imidazol‐4‐ol in HNO₃/Ac₂O followed by cyclization of the di‐enol. It was characterized by NMR, IR, elemental analysis, and single‐crystal X‐ray diffraction analysis. Compound DNTNDI crystallizes in the orthorhombic space group P2(1)2(1)2(1). The thermal decomposition was studied with thermogravimetry/derivative thermogravimetry (TG/DTG) in a nitrogen atmosphere with a heating rate of 5 K min⁻¹. The TG/DTG analysis indicated that DNTNDI has 97.64 % mass loss between 127 °C and 173 °C by undergoing exothermic decomposition. The density of DNTNDI was determined as 1.906 g cm⁻³ at 293 K with an Ultrapycno 1000 Pycnometer. The denotation velocity and denotation pressure of DNTNDI were calculated as 9325 m s⁻¹ and 40 GPa by applying the LOTUSES (version 1.4) code, respectively. The oxygen balance of DNTNDI is 0 and its oxygen content amounts to 51.78 %, which is superior to that of new generation of chlorine‐free oxidizer ammonium dinitramide (ADN).     

Two photoluminescent polymers based on fluorene and 2,4,6‐triphenyl pyridine: Synthesis and electroluminescence

Two fluorene and triphenyl pyridine‐based linear and dendronized copolymers, P1 and P2 , were synthesized and fully characterized by ¹H‐NMR, ¹³C‐NMR, and matrix assistant laser desorption/ionization time‐of‐flight mass spectra, respectively. The absorption, photoluminescence (PL) behavior, and energy band gaps of P1 and P2 relative to those of polyfluorene end‐capped with benzene ( P0 ) were examined through UV–vis, photoluminescent spectra, and cyclic voltammetry. The UV–vis absorption and PL emission behavior of P0 and P1 were hardly affected by molecular architecture, while those of P2 were strongly correlated with the dendronized molecular frameworks. Cyclic voltammetry studies indicated the lower highest occupied molecular orbital energy level and wider band gap of P2 thin solid film relative to those of P0 and P1 . The new polymers were thermally stable up to 410°C. The better luminance and external quantum efficiencies of P1 relative to those of P0 in polymer light‐emitting diode (PLED) applications are due to improved electron injection, charge trapping and recombination at the pyridine sites. Through the experiments, it is found that the triphenyl pyridyl segments and excimers‐formation make pronounced contribution to long wavelength emission in P1 ‐based blue light‐emitting materials, and the analogous materials containing 2,4,6‐triphenyl pyridyl unit of P1 constitute highly attractive materials for white PLED applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012