Synthesis, crystal structure, spectroscopy and electroluminescence of zinc(II) complexes containing bidentate 2-(2-pyridyl)quinoline derivative ligands

Three bidentate ligands, 4-phenyl-2-(2-pyridyl)-quinoline (ppq), 6-(carbazol-9-yl)-4-phenyl-2-(2-pyridyl)-quinoline (cpq) and 6-diphenylamino-4-phenyl-2-(2-pyridyl)-quinoline (dpq) and their zinc(II) complexes, have been designed and synthesized. The crystal structure of [Zn(ppq)(2)Cl]PF6 shows that the central zinc atom is coordinated with one chloride and four nitrogen atoms from two ligands. The introduction of an electron-donating substituent such as carbazole or an aromatic amine group at the 6-position of the quinoline moiety can generate colored tunable Zn complexes, and the photoluminescence (PL) wavelength was modulated from 418 nm for [Zn(ppq)(2)Cl]PF6 to 591 nm for [Zn(cpq)(2)Cl]PF6 and 638 nm for [Zn(dpq)(2)Cl]PF6 in CH2Cl2 solution. The electroluminescence spectrum of [Zn(dpq)(2)Cl]PF6 exhibits pure red light emission with the Commission Internationale de L'Eclairage (CIE) coordinates (0.63, 0.36) and a maximum at 648 nm.

Synthesis, characterization, photoluminescent and electroluminescent properties of new conjugated 2,2 '-(arylenedivinylene)bis-8-substituted quinolines

A series of new PPV oligomers containing 8-substituted quinoline, 2,2'-(arylenedivinylene) bis-8-quinoline derivatives, were designed and synthesized via a Knoevenagel condensation reaction of quinaldine, 8-hydroxy-or 8-methoxy-quinaldine with aromatic dialdehydes. These PPV oligomers were characterized by H-1 and C-13-NMR, X-ray diffraction, elemental analysis, UV-visible and fluorescence spectroscopies. The X-ray diffraction investigation showed that there are intermolecular pi...pi interactions in the solid state in 1 and 3. The optical and photoluminescent properties study demonstrated that the emission color of the resulting materials varies from blue to yellow and is dependent on the substituents (pi-donor and pi-acceptor groups) on both sides of the conjugated molecules and the aromatic core in the middle of the conjugated backbones. The electroluminescent devices using compounds 1-4 as the emitters and electron-transporting layers were fabricated with the structure ITO/NPB/emitter/LiF/Al. The best device performance with the maximum brightness of 5530 cd m(-2) and the luminous efficiency of 2.4 cd A(-1) is achieved by using compound 4, with intramolecular charge transfer character, as the emitter; these values represent a more than 5-fold improvement in brightness and efficiency compared to compound 3 without methoxy groups on the phenyl rings.

Tetra-mu-alpha-alanine-bis[tetraaquagadolinium(III)] hexaperchlorate

The title complex, [Gd-2 (C3H7NO2)(4)(H2O)(8)](ClO4)(6), contains centrosymmetric dimeric [Gd-2 (Ala)(4) (H2O)(8)](6+) cations (Ala is alpha-alanine) and perchlorate anions. The four alanine molecules act as bridging ligands linking two Gd3+ ions through their carboxylate O atoms. Each Gd3+ ion is also coordinated by four water molecules, which complete an eightfold coordination in a square-antiprism fashion. The perchlorate anions and the methyl groups of the alanine ligands are disordered.

Synthesis and crystal structure of bis(tetrahydrofurfurylindenyl) lanthanide chlorides

Lanthanocene chlorides (C4H7OCH2C9H6)(2)LnCl[Ln=Y(1); Ln=Gd(2)] were synthesized by the reaction of tetrahydrofurfurylindenyl lithium(in situ) with corresponding anhydrous lanthanide chorides in THF. The crystal structures of these two complexes were determined by X-ray diffraction and they were unsolvated monomeric complexes. They were stable in the air for several hours. Complexes 1 and 2 belong to the same crystal system (orthorhombic) and space group(P2(1)2(1)2(1)). The unit cell dimensions of complex 1 were a=1.042 52(9) nm, b=1.47455(12) nm, c=1.497 99(13) nm, Z=4, D-c=1.508 g/cm(3); The unit cell dimensions of complex 2 were a=1.037 01(10) nm, b=1.472 33(12) nm, c=1.513 54(14) nm, Z=4, D-c=1.699 g/cm(3). They have the same structure and different space configurations. The central metal atom is coordinated by two indenyl, two oxygen of the tetrahydrofurfuryl and one chlorine atom to form a distorted trigonal bipyramid.

Syntheses and crystal structures of bis(tetrahydrofurfurylindenyl) lanthanocene chlorides (C4H7OCH2C9H6)(2)LnCl (Ln = Nd, Sm, Dy, Ho, Er, Yb)

Reaction of anhydrous lanthanide trichlorides with tetrahydrofurfuryl indenyl lithium in THF afforded bis(tetrahydrofurfurylindenyl) lanthanocene chlorides complexes (C4H7OCH2C9H6)(2) LnCl, Ln = Nd (1), Sm (2), Dy (3), Ho (4), Er (5), Yb (6). The X-ray crystallographic structures of all the six complexes were determined and these indicate that they are unsolvated nine-coordinate monomeric complexes with a trans arrangement of both the sidearm and indenyl rings in the solid state. They belong to the same crystal system (orthorhombic) and space group (P2(1)2(1)2(1)) with the same structure. Especially, they are more stable to air and moisture than the corresponding unsubstituted indenyl lanthanide complexes.

Synthesis, characterization and molecular structure of a novel asymmetrical half-sandwich binuclear iron carborane complex Cp ' Fe-2(2)(CO)(3)(Se2C2B10H10)

The half-sandwich methylcyclopentadlenyl iron carbonyl complex reacted with 1,2-dilithium diselenolate carborane Li2Se2C2B10H10 (1) which was produced by the insertion of element Se into 1, 2-dilithium carborane to give a half-sandwich binuclear iron carborane complex Cp'Fe-2(2)(CO) 3Se2C2B10H10 (3). X-ray structural analysis of complex 3 reveals that one of the iron atoms is chiral.

Polymerized unsymmetrical iron post-metallocene catalyst for ethylene polymerization

The unsymmetrical allyl containing post-metallocene complex [ArN = C( Me)] [(ArN)-N-' = C(Me)]C5H3NFeCl2 [Ar = 2,6(i- Pr)(2)C6H3, Ar' = 4-allyl-2,6-(i-Pr)(2)C6H3] (3) has been prepared and characterized. Complex (3) can be co-polymerized with styrene in the presence of radical initiator to produce polymerized post-metallocene catalyst which exhibits high activity for ethylene polymerization (2.5 x 10(6) g PE/mol Fe.h).

Extraction and separation of thorium and ytterbium with bis (2,4,4-trimethylpentyl) phosphinic acid using a hollow fiber membrane extractor

The based membrane extraction of Th4+ and Yb3+ was studied in HBTMPP-heptane using a hollow fibber membrane. The separation method of Th4+ and Yb3+ was proposed by kinetics competition. The separation operation of Th4+ and Yb3+ mixture was carried out by two successive extraction and stripping simultaneously. The concentration ratio of Th4+ to Yb3+ is 16.74 in the stripping solution. The recovery and purity of Th4+ are 71.6% and 95.74% respectively.

Networks with hexagonal circuits in co-ordination polymers of metal ions (Zn-II, Cd-II) with 1,1 '-(1,4-butanediyl)bis(imidazole)

Three new compounds, [ZnL1.5(H2O)(SO4)]. 6H(2)O 1, [ZnL1.5(H2O)(2)][NO3](2). 2H(2)O 2 and [CdL1.5(H2O)(2)(SO4)]. 4H(2)O 3 were obtained from self-assembly of the corresponding metal salts with 1,1'-(1,4-butanediyl)bis(imidazole) (L). In both 1 and 2 zinc ion is five-co-ordinated, showing a less-common trigonal bipyramidal co-ordination polyhedron, while cadmium ion of 3 is six-co-ordinated with a common octahedral arrangement. The sulfate ions of 1 and 3 are co-ordinated, however the nitrate ions of 2 are not. Each of the three compounds is composed of a (6, 3) network with the hexagonal smallest circuit containing six metal ions and six L; each L is co-ordinated to two metal ions, acting as a bridging ligand. In 1 the 2-D sheet of (6, 3) networks is interpenetrated in an inclined mode by symmetry related, identical sheets to give an interlocked 3-D structure, while the (6, 3) networks of both 2 and 3 stack in a parallel fashion to construct frameworks having channels.

Phase transition and transition kinetics of a thermotropic poly(amide-imide) derived from 70% pyromellitic dianhydride, 30% terephthaloyl chloride, and 1,3-bis[4-(4 '-aminophenoxy)cumyl]benzene

The phase transition and transition kinetics of a liquid crystalline copoly(amide-imide) (PAI37), which was synthesized from 70 mol% pyromellitic dianhydride, 30 mol% terephthaloyl chloride, and 1,3-bis[4-(4'-aminophenoxy)cumyl]benzene, was characterized by differential scanning calorimetry, polarized light microscopy, X-ray diffraction, and rheology. PAI37 exhibits a glass transition temperature at 182 degreesC followed by multiple phase transitions. The crystalline phase starts to melt at similar to 220 degreesC and forms smectic C (S-C) phase. The Sc phase transforms into smectic A (S-A) phase when the temperature is above 237 degreesC. The S-C to S-A transition spans a broad temperature range in which the S-A phase vanishes and forms isotropic melt. The WARD fiber pattern of PAI37 pulled from the anisotropic melt revealed an anomalous chain orientation, which was characterized by its layer normal perpendicular to the fiber direction. The transition kinetics for the mesophase and crystalline phase formation was also studied.

Allyl containing iron post-metallocene catalyst for ethylene polymerization

Tridentate ligand[(2,6-ArN=C(Me))(2)C5H3N](Ar=4-allyl-2,6-(i-Pr)(2)C6H3)(4)which contains allyl groups on each aryl ring was ready prepared and reacted with FeCl2. 4H(2)O to give the precatalyst [(2,6-ArN=C(CH3))(2)C5H3N]. FeCl2 (5). Compounds 2-5 were characterized by H-1 NMR, EI-MS,and IR. The complex 5 which was actived by methylaluminoxane(MAO) exhibits high activity for ethylene polymerization [1.9 x 10(6) g pE.(mol Fe . h)(-1) at 0 degreesC]. It was showed that the activity was decreased with increasing temperature and the polymer product was highly linear PE with (M) over bar (eta) varying from 50000 to 260000.

Polyimides from 3,3 '-dioxo-[1,1 ']-spirodiphthalan-5,5 ',6,6 '-tetracarboxylic dianhydride

A novel dianhydride, 3,3'-dioxo-[1,1']-spirodiphthalan-5,5',6,6'-tetracarboxlic dianhydride, was synthesized and used as a monomer to prepare polyimides with several diamines via a conventional two-stage procedure. The intermediate poly(amic-acid)s had inherent viscosities of 0.84-1.71 dL/g and could be thermally converted into lightly yellow, transparent, flexible and tough films. Films cast from chemically imidized polyimides were transparent and colorless. The glass transition temperatures (Tg) were > 400 degrees C, and the 5% weight-loss temperatures were > 420 degrees C in N-2 and in air. The solubilities of these polyimides in various solvents were evaluated. The mechanical properties of some polyimides were also tested. (C) 1999 Elsevier Science Ltd. All rights reserved.

Synthesis, electrical properties and crystal structure of a new radical-ion salt based on pi-extended bis(TTF) and a Keggin heteropolymolybdate

By electrocrystallization of 2,6-[4,5-bis(n-butylsulfanyl)-1,3-dithiol-2-ylidene]-4,8-bis(6-iodo-n-hexyloxy)-1,3,5,7-tetrathia-s-indacene (BHBDTI) and [NBu4](4)[SiMo12O40] in the mixed solvent CHCl2CH2Cl and CH3CN, the new radical-ion salt [C42H60Cl2O2S12](2)[SiMo12O40] was prepared. It was characterized by means of IR and ESR spectroscopy and X-ray diffraction. In the crystal structure, organic radical dications and silicomolybdate anions are alternatively arranged along the a axis to form a 1-D conducting layer. The organic layer consists of two isolated groups of BHBDTI divided by the (011) plane without short interatomic contacts. However, in each group, BHBDTI molecules associate with each other in a head to tail manner running along the [011] direction and face-to-face overlapping with a relative shift by approximately one TTF subunit along the long axis of the molecule and a slight shift along the short axis of the molecule with significantly short S ... S contacts. The room-temperature d.c. conductivity determined by the two-probe method is 10(-4) S cm(-1), suggesting that the compound is a semiconductor.

Effect of lanthanum ions on tRNA(Phe) structure: Imino proton NMR spectroscopy

The effect of lanthanum ions on the structural and conformational change of yeast tRNA(Phe) was studied by H-1 NMR. The results suggest that the tertiary base pair (G-15)(C-48), which was located in the terminal in the augmented dihydrouridine helix (D-helix), was markedly affected by adding La3+ and shifted 0.33 downfield. Based pair (U-8)(A-14), which is associated with a tertiary interaction, links the base of the acceptor stem to the D-stem and anchors the elbow of the L structure, shifted 0.20 upfield. Another imino proton that may be affected by La3+ in tRNA(Phe) is the tertiary base pair (G-19)(C-56). The assignment of this resonance is tentative since it is located in the region of highly overlapping resonances between 12.6 and 12.2. This base pair helps to anchor the D-loop to the T psi C loop.

Rapid automated in-situ monitoring of total dissolved iron and total dissolved manganese in underground water by reverse-flow injection with chemiluminescence detection during the process of water treatment

Measurement of iron and manganese is very important in evaluating the quality of natural waters. We have constructed an automated Fe(II), total dissolved iron(TDI), Mn(II), and total dissolved manganese(TDM) analysis system for the quality control of underground drinking water by reverse flow injection analysis and chemiluminescence detection(rFIA-CL), The method is based on the measurement of the metal-catalyzed light emission from luminol oxidation by potassium periodate. The typical signal is a narrow peak, in which the height is proportional to light emitted and hence to the concentration of metal ions. The detection limits were 3 x 10(-6) mu g ml(-1) for Fe(II) and the linear range extents up to 1.0 x 10(-4) and 5 x 10(-6) mu g ml(-1) for Mn(II) cover a linear range to 1.0 x 10(-4) mu g ml(-1). This method was used for automated in-situ monitoring of total dissolved iron and total dissolved in underground water during water treatment. (C) 1997 Elsevier Science B.V.