2,5-二辛氧基聚对苯的合成及表征

蓝色电致发光;2;5-二辛氧基聚对苯的合成及表征     

Synthesis and photovoltaic performances of 2,5-dioctyloxy-1,4-phenylenevinylene and terthiophene copolymers with di(p-tolyl)phenylamine and oxadiazole side groups

Three novel conjugated polymers (P1, P2, and P3), comprised of 2,5-dioctyloxy-1,4-phenylenevinylene and terthiophene derivatives with/without di(p-tolyl)phenylamine (TPAV) and oxadiazole (OXD) side groups, have been synthesized via the Witting-Horner reaction. The effect of TPAV and OXD side groups on the optical, electrochemical and photovoltaic properties has been investigated. It is found that the introduction of TPAV and OXD side groups to the backbone of P2 and P3 exhibits broader and stronger absorption than that of P1 without TPAV and OXD side groups. Photovoltaic cells have been fabricated with the as-synthesized polymers as the donors and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as the acceptor in a 1:4 weight ratio. The device based on P2 shows a maximum power conversion efficiency of 1.75% under simulated AM 1.5 G solar irradiation (100 mW/cm²).     

Synthesis and characterization of poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene)

Poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene) (PTFPV) was prepared for the first time by the Stille cross-coupling reaction and the resulting material was characterized through MALDI-TOF mass spectrometry, employing a novel sample preparation protocol suitable for insoluble compounds; preliminary optical and electrooptical measurements were performed.     

Synthesis and electrical conductivity of poly(1,4-phenylenevinylene-co-2-nitro-1,4-phenylenevinylene)

A series of PPV copolymers containing 2-nitro-1,4-phenylenevinylene (NO₂-PV) units were prepared via the water-soluble precursor route. They were obtained in film form and were doped with I₂ and FeCl₃. Doping increased the electrical conductivities to maximum values of about 3×10^?2 and 3×10^?1 s cm^?1, respectively, for the two dopants. Conductivity depended strongly on the composition of the copolymers; it reached a maximum value at ca. 1–2 mol % of NO₂-PV units in the copolymers and then dropped rapidly with further increase in NO₂-PV content. Electronic effects of the substituent and morphological changes induced by copolymerization appear to interplay intricately, resulting in the occurrence of a maximum conducting composition. © 1993 John Wiley & Sons, Inc.     

Crystal structure of poly(p-benzamide)

Redetermination of the crystal structure of poly(p-benzamide) was made by using newly collected intensity data. The molecular conformation is TCTC, where the internal rotation angles about the N? C bond of the amide group and about the virtual bond of N-phenyl-C are T (trans) and C (cis) conformations, respectively. Two molecular chains pass through a rectangular unit cell with dimension, a = 7.75 Å, b = 5.30 Å, c (fiber axis) = 12.87 Å, and the space group, P2₁2₁2₁-D. The reflection observed at the spacing of 010 may be attributed to the reflection due to another crystal polymorph or the diffuse scattering due to disorder. © 1993 John Wiley & Sons, Inc.     

Preparation of soluble and fusible poly(2,5-dimethoxy-1,4-phenylene)

Poly(2,5-dimethoxy-1,4-phenylene) was prepared by oxidative polymerization of p-dimethoxybenzene with aluminum chloride and copper(II) chloride in nitrobenzene under reduced pressure. The polymers obtained were soluble in sulfuric acid and fusible at 320°C. The intrinsic viscosity of the polymer was ca. 0.07 in sulfuric acid. Demethylation of methoxy groups did not occur during the polymerization.     

Preparation and characterization of a novel poly(1,4-phenylenevinylene) derivative with an azobenzene side chain

A novel poly(1,4-phenylenevinylene) (PPV) derivative containing an azobenzene side chain was prepared via a dehydrochlorination route. Poly{2-methoxy-5-[(4-(4-methoxyphenylazo)phenyloxy)-hexyloxy]-1,4-phenylenevinylene}, which is soluble in ordinary solvents such as chloroform, tetrahydrofuran (THF), acetone, xylene, etc., was characterized by FTIR, ¹H NMR, GPC, and UV-visible spectroscopies, thermogravimetric analysis (TGA), and cyclic voltammetry. The photoluminescence spectrum of the polymer showed an emission maximum at λ = 550 nm.     

Crystal structure of poly(dithiotriethylene adipate)

The crystal structure of poly(dithiotriethylene adipate) has been determined through the best fitting of calculated and experimental X‐ray diffraction powder profiles. A triclinic cell was found with dimensions a = 4.942 (7) Å, b = 4.702 (2) Å, c = 20.56 (2) Å, α = 88.9 (2)°, β = 61.0 (1)°, γ = 67.8 (1)°, P‐1 space group, and one chain in the unit cell. A full extended trans conformation of the chain fitted satisfactory the experimental data, yielding to a discrepancy factor R_p = 0.073. A comparison between the crystal structures of poly(dithiotriethylene adipate) and poly (thiodiethylene adipate) is proposed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2677–2682, 2005     

Crystal structure of poly(m-phenylene isophthalamide)

The crystal structure of poly(m-phenyulene isophthalamide) was determined by x-ray analysis. The triclinic cell, with a = 5.27 Å, b = 5.25 Å, c (fiber axis) = 11.3 Å, α = 111.5°, β = 111.4° and γ = 88.0° and space group P1, contains one monomeric unit. The crystal density is 1.47 g/cc. The molecules in the crystal are contracted by 1 Å per monomeric unit from the fully extended conformation, and the planes of the benzene rings and adjacent amide groups make angles of about 30°. The crystal is composed of molecular chains connected by N? H···O hydrogen bonds along the a and b axes forming a “jungle gym” network structure. The low tensile modulus of this polymer as compared with that of poly(p-phenylene terephthalamide) is attributed to the contracted molecular conformation.     

Structure of friction-transferred highly oriented poly(3-hexylthiophene) thin films

Oriented thin films of P3HT were obtained by a friction-transfer technique. The morphology and structure of the film were studied by means of optical microscopy, atomic force microscopy and transmission electron microscopy. Optical microscopy observation indicates that large size well-ordered P3HT thin films can be produced by a friction-transfer technique. Highly ordered lamellae were observed in P3HT friction-transferred films by electron microscopy. Electron diffraction results confirm the existence of high orientation with the a- and c-axes of P3HT crystals aligned in the film plane while the c-axis parallel to the friction-transfer direction. The atomic force microscopy observation of the as-prepared P3HT thin film shows, however, a featureless top surface morphology, indicating the structure inhomogeneity of the obtained film. To get highly oriented P3HT thin films with homogenous structure, high temperature annealing, solvent vapor annealing and self-seeding recrystallization of the friction-transferred film were performed. It is confirmed that solvent vapor annealing and self-seeding recrystallization methods are efficient in improving the surface morphology and structure of the frictiontransferred P3HT thin film. Highly oriented P3HT films with unique structure can be obtained through friction-transfer with subsequent solvent vapor annealing and self-seeding recrystallization.     

Synthesis and crystal structure of cyclopentadienyl(1,4-dimethyl-1,4-dibora-2,5-cyclohexadiene)cobalt

The synthesis of the organometallic derivative cyclopentadienyl(1,4-dimethyl-1,4-diboracyclohexa-2,5-diene)cobalt is described. This complex, [(CH₃BC₄H₄BCH₃)Co(η-C₅H₅)], forms red-oranged monoclinic crystals, space group P2₁/a with Z = 4 in a unit cell of dimensions a 11.362(7), b, 7.467(7), c 13.290(12) Å, β 103.76(6)°. The structure has been elucidated by heavy-atom methods from 1732 reflections (I > 2σ(I)) measured on a Syntex P2₁ four-circle diffractometer and refined to R = 0.055. In the coordination complex all six atoms of the cyclohexadiene ring are within bonding distance of the metal atom, but the two boron atoms bend away from the metal atom, and the ring elongates slightly in the B---B direction. As a standard of comparison the known geometry of the free ligand [1,4-difluoro-1,4-dibora-2,3,5,6-tetramethylcyclohexa-2,5-diene] is used. The terminal methyl groups on the boron atoms, by contrast, bend slightly back towards the metal atom. The cyclopentadienyl ring remains planar but is positionally disordered.     

Cyclophanes—13: Crystal and molecular structure of [2.2][2,5]furano(1,4)naphthalenophane

The crystal and molecular structure of [2.2](2,5)furano(1,4)naphthalenophane (1) was determined by X-ray crystallography. The molecule exists in the anti-conformation and the study represents the first instance in which the structural features of a naphthalenoid ring within a cyclophane were determined. Crystals of cyclophane 1 are orthorhombic, space group Pbca, with a = 7.859(2). b = 11.482(3) and c = 28.818(8) Å. While the nonbridged portion of the naphthalenoid ring is planar, the portion which is bridged to the furanoid ring through its 1 and 4 C atoms is puckered and boat-shaped. These C atoms are positioned 14° out of the plane of the other four C atoms of this ring. The furanoid ring is essentially planar but is not parallel to the naphthalenoid ring. It is inclined 22° to the least squares plane of the bridged portion of the naphthalenoid ring. This angle of inclination staggers the atoms of the furanoid and bridged naphthalenoid ring and positions the 3 and 4 C atoms, the 2 and 5 C atoms and the 0 atom of the furanoid ring 3.4. 2.9 and 2.6 Å. respectively, from the least squares plane of the bridged portion of the naphthalenoid ring. While the internal angles around the bridging C atoms α- to the naphthalenoid ring are 109°, those α- to the furanoid ring are 113°. In addition unusually large bond angles ($\text{\$}\text{?}$137°) at the 2 and 5 C atoms of the furanoid ring, external to the ring, are also observed. The distortions are considered with respect to the strain within the cyclophane macrocycle and are compared with other similar systems.     

Crystal structure of poly(ethylene-oxide) supramolecular assemblies

The formation of poly(ethylene oxide) (PEO) supramolecular complexes is discussed in terms of intermolecular interactions and molecular packing. On the basis of the different known crystal structures, several mechanisms are proposed. First, the PEO complexes can be formed by an Intercalation or Inclusion process, guest molecules diffusing into the PEO unit cell. On the other hand, molecular complexes based on hydrogen bonding cannot be obtained by such a way, their formation requires the complete removal of the initial PEO structure either by melting or dissolution. Finally the relations between the crystal lamellar morphology, the host-guest interactions and the PEO chain mobility are discussed.     

Crystal structure of 1-cyclohexylpiperazine-1,4-diium dichromate(VI)

Single crystals of 1-cyclohexylpiperazine-1,4-diium dichromate(VI), (C₁₀H₂₂N₂)[Cr₂O₇], were obtained by slow evaporation at room temperature from an aqueous solution of potassium dichromate, hydrochloric acid and 1-cyclohexylpiperazine. (C₁₀H₂₂N₂)[Cr₂O₇] is triclinic (P\(\bar 1\)) with a = 10.351(2) Å, b = 12.766(3) Å, c = 6.111(1) Å, α = 91.50(2)°, β = 104.26(3)°, γ = 94.91(2)°, V = 778.8(3) ų, and Z = 2. The structure determination performed from single crystal X-ray diffraction data leads to R₁/wR₂ reliability factors of 0.032/0.078. The asymmetric unit of the title salt C₁₀H₂₂N₂²⁺·Cr₂O₇^2?, consists of one 1-cyclohexylpiperazine-1,4-diium dication and one dichromate dianion. These entities are linked together by N–H···O hydrogen bonds to form {(C₁₀H₂₂N₂)[Cr₂O₇]}_n infinite chains lying parallel to the (100) plane and running along the c axis. The intermolecular N–H···O hydrogen bonds link these chains into a two-dimensional network structure consolidated through C–H···O weak interactions.