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1.
A series of conjugated and non-conjugated copolymers of poly(2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene-co-styrene) were synthesized via a typical chlorine precursor route. The obtained copolymers were characterized by FTIR spectra,
UV-Vis spectra, 1H NMR and GPC. The results obtained indicated that the introduction of non-conjugated PS segments in MEH-PPV led to the interruption
of conjugation structure and shortened the effective conjugated length, by which the optical properties of the conjugated
polymer can be adjusted. 相似文献
2.
H. R. Manjunath S. Naveen C. S. Ananda Kumar S. B. Benaka Prasad M. V. Deepa Naveen M. A. Sridhar J. Shashidhara Prasad K. S. Rangappa 《Journal of Structural Chemistry》2011,52(5):959-963
The title compound 1′-Benzyl-8-(4-fluorobenzyl)-8-azaspiro[bicyclo[3.2.1] octane-3,4′-imidazolidine]-2′,5′-dione, C23H23FN3O2 is synthesized and the structure is investigated by X-ray diffraction studies. The compound crystallizes in the triclinic
crystal class in the P1 space group. The hydantoin ring adopts a planar conformation and is affected by the π conjugation. The pyrrolidine and piperidine
rings in the bicyclo octane moiety adopt envelope and chair conformations respectively. The structure exhibits both inter-
and intramolecular hydrogen bonds of the type N-H...O, C-H...O, and C-H...N. The oxygen atom in the hydantoin ring simultaneously
accepts two hydrogen bonds to form a three-centered hydrogen bonding pattern. 相似文献
3.
Guo-Cheng Liu Yong-Qiang Chen Wen-Yan Zheng Hong-Yan Lin 《Transition Metal Chemistry》2009,34(7):739-744
A novel organic–inorganic hybrid compound [Cu(2,2′-bipy)(C6H5NO2)(H2O)]2[Mo8O26]·5H2O (1), (2,2′-bipy = 2,2′-bipyridine; C6H5NO2 = pyridine-4-carboxylic acid) has been prepared and characterized by elemental analyses, IR spectrum, thermal stability analysis,
and single-crystal X-ray diffraction. Compound 1 is a discrete cluster, constructed from β-[Mo8O26]4− subunits covalently bonded to two [Cu(2,2′- bipy)(C6H5NO2)(H2O)]24+ coordination cations via terminal oxo groups that connect one molybdenum site. A 3D supramolecular network is further formed
by extensive hydrogen bonding interactions and π–π interactions of the 2,2′-bipy and pyridine-4-carboxylic acid ligands. EPR
and magnetic susceptibility studies have been used to elucidate the electronic properties of the Cu2+ centres, and the results are in good agreement with the structural features of the compound. 相似文献
4.
Copolymerization of an optically active N-(1-menthyl carboxylatomethyl)citraconimide (MCMCI) was carried out with methyl methacrylate (MMA) with azobisisobutyronitrile as the initiator in benzene at 50°C. All the copolymers obtained were optically active. After the removal of the optically active menthyl group, the hydrolyzed poly(MCMCI-co-MMA)'s still showed optical activity. The asymmetric induction to the copolymer main chain and the mechanism are discussed based on the measurements of optical rotatory dispersion and circular dichroism of the original and hydrolyzed copolymers. 相似文献
5.
B. S. Fedorov N. I. Golovina V. V. Arakcheeva M. A. Fadeev G. V. Strukov V. V. Kedrov G. V. Shilov L. O. Atovmyan 《Russian Chemical Bulletin》1999,48(8):1584-1586
The reaction ofN,N′-bis(2-nitroxyethyl)pyridine-2,6-dicarboxamide with PdCl2 afforded previously unknowncis-(N-2-nitroxyethylpicolinamide-N,N′)dichloropalladium(II) andcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(II), which were isolated as a cocrystallizate of the molecular compounds. Its structure was established
by X-ray diffraction analysis.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1604–1606, August, 1999. 相似文献
6.
Minqin Li P. R. Srikanth Sharma Harry L. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1998,36(4):553-561
Two-component simultaneous interpenetrating networks (IPN) of thepoly(4′-[[2-(methylacryloxy)ethyl]ethylamino]-4-nitroazobenzene-co-methyl meth-acrylate) (PDR1MA-co-MMA)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) system, the PDR1MA/PPO system and 4′-[[2-(acetoxy)ethyl]ethylamino]-4-nitroazo benzene (ACDR1) doped MMA/PPO system were synthesized and characterized. As studied by differential scanning calorimetry (DSC) the full IPNs of the PDR1MA-co-MMA/PPO system and the PDR1MA/PPO system showed a single Tg varying with the PPO composition. A single-phase morphology of the full IPNs was also indicated by scanning electron microscopy (SEM). Transparent films were cast onto clean microscopic glass slides and poled at 190°C for 1 h. The UV-VIS absorption spectra of the three IPN systems before and after curing and corona poling showed a shift in the maximum absorption due to the induced alignment of the nonlinear optical chromophores in the IPN systems. The absorption intensity of the full IPNs remained same after heating at 120°C for 72 h, indicating that the electric field-induced alignment is stable in the full IPN materials. Preliminary second harmonic generation (SHG) data on these IPNs are presented. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 553–561, 1998 相似文献
7.
We investigate the nonlinear third-order polarizabilities of novel sandwichlike clusters [Al4MAl4]n− (n = 0–2, M = Ti, V and Cr). The calculations have been performed by employing time-dependent density functional theory combined with sum-over-states
method. The results show that these complexes possess remarkably large third-order static polarizability, and change of a
metal centre has a great influence on the third-order nonlinear optical properties. The calculated third-order polarizability
follows: [Al4CrAl4] > [Al4VAl4]− > [Al4TiAl4]2−. Analysis of the main contributions to the third-order polarizability suggests that charge transfer () along the z-axis direction plays a key role in the nonlinear optical response.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
Abstract Sodium 4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate (1) is synthesized by the sulfonation of 6-hydroxybiochanin A and its structure is characterized by elemental analysis, 1H-NMR, and IR spectroscopy. It is assembled with cobalt(II) or zinc(II), hexaquacobalt(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate)
tetrahydrate (2) and hexaquazinc(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (3) are obtained and characterized by IR spectroscopy. Simultaneously, their three-dimensional structures are determined by
single-crystal X-ray analysis. It turns out that 2 and 3 are isomorphous and crystallize in the triclinic crystal system, space group P-1. Hydrophilic regions are defined by O–H···O hydrogen bonds involving the coordinated water molecules, the included water
molecules, and sulfonate groups. Aromatic π...π stacking interactions assemble the isoflavone skeletons into columns and these
columns formed hydrophobic regions. The sulfonate group is an important bridge as a structural link between the hydrophilic
regions and the hydrophobic regions. Hydrogen bonds, π...π stacking interactions and the electrostatic interactions assemble
2 and 3 into three-dimensional network structures.
Graphical abstract Sodium 4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate (1) is synthesized and assembled with cobalt(II) or zinc(II). Hexaquacobalt(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate)
tetrahydrate (2) and hexaquazinc(II) bis(4′-methoxy-5,6,7-trihydroxyisoflavone-3′-sulfonate) tetrahydrate (3) are obtained and determined by single-crystal X-ray analysis. It turns out that 2 and 3 are isomorphous and assembled into three-dimensional network structures, characterized by hydrophilic regions defined by
hydrogen bonds involving the coordinated water molecules, the included water molecules, and the sulfonate groups and by hydrophobic
columns, formed by the isoflavone skeletons, interacting through π...π stacking interactions.
相似文献
9.
The preparation of polyvinylpyrrolidone (PVP) microspheres in ethyl acetate by dispersion polymerization with N-vinylpyrrolidone (NVP) as initial monomer, poly(N-vinylpyrrolidone-co-vinyl acetate) (P (NVP-co-VAc)) as dispersant, and 2, 2′-azobisisobutyronitrile(AIBN) as initiator is reported. The influences of monomer concentration,
dispersant concentration and initiator concentration on the size of PVP microspheres as well as the monomer conversion were
studied. The structure and properties of PVP microspheres were analyzed. The results show that the prepared PVP microspheres
have a mean diameter of 3-4 μm. With an increase in NVP concentration, the size and the molecular weight of the PVP microspheres
as well as the monomer conversion all increase. With increasing P(NVP-co-VAc) concentrations, the PVP molecular weight and monomer conversion both increase while the size of the microspheres becomes
smaller. As the concentration of AIBN increases, the microsphere size and monomer conversion increase whereas the PVP molecular
weight decreases. The PVP prepared by dispersion polymerization has a crystal structure, and its molecular weight is lower
compared to that prepared by solution polymerization.
__________
Translated from Acta Polymerica Sinica, 2007, 11 (in Chinese) 相似文献
10.
Kazuo Sugiyama Satoshi Mitsuno Kohei Shiraishi 《Journal of polymer science. Part A, Polymer chemistry》1997,35(16):3349-3357
A series of microspheres composed of methyl methacrylate (MMA) and N-(2-hydroxypropyl)methacrylamide (HPMA), and/or 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), i.e., binary copolymer microspheres [poly(HPMA-co-MMA)KPS and poly(HPMA-co-MMA)ABIP] and ternary ones [poly(HPMA/MPC-co-MMA)KPS and poly(HPMA/MPC-co-MMA)ABIP], were prepared by emulsifier-free emulsion copolymerization using potassium peroxodisulfate (KPS) or 2,2′-azobis[2-(imidazolin-2-yl)propane] dihydrochloride (ABIP) as initiators. The decrease in ζ-potential of the polymer microspheres is caused by the addition of the HPMA and/or MPC moieties. Equilibrium water content of poly(HPMA-co-MMA)ABIP showed a remarkable swelling change with a change in response to temperature: the hydrated conformation at 28°C and the dehydrated one at above 40°C. The adsorption of protein on the polymer microspheres also changed in response to change in temperature. The ternary polymer microspheres effectively suppressed the adsorption both of Alb and Glo, less than binary ones. A series of polymer microspheres are expected to apply as a novel drug carrier with both thermosensitive and nonthrombogenic functions. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3349–3357, 1997 相似文献
11.
Sumitava Khan Subhasis Roy Kishalay Bhar Partha Mitra Alexandra M. Z. Slawin Barindra Kumar Ghosh 《Transition Metal Chemistry》2011,36(1):99-106
Two hexacoordinated mononuclear Co(III) compounds of the type cis-[Co(L)(N3)2] X [1, X = ClO4; 2, X = PF6; L = N,N′-(bis(pyridine-2-yl)benzylidine)-1,4-butanediamine] have been synthesized and characterized by physicochemical and spectroscopic
methods. The crystal structures of complexes 1 and 2 both have distorted octahedral geometry with two terminal azides in mutual cis orientations. In the crystalline state, two
mononuclear units of 1 are associated by weak C–H…π interactions to produce a dimeric unit, which packs through C–H…O hydrogen bonds and π…π interactions
leading to a 2-D continuum. The mononuclear units in 2 are engaged in weak cooperative intermolecular C–H…π interactions and multiple C–H…F hydrogen bonds giving rise to a 3-D
network structure. These diamagnetic compounds are redox active and show luminescence in DMF solutions. 相似文献
12.
I. G. Sushchenko T. K. Meleshko I. V. Gofman T. E. Sukhanova M. E. Vylegzhanina I. V. Abalov E. N. Vlasova E. N. Popova V. E. Yudin A. V. Yakimanskii 《Polymer Science Series A》2011,53(9):800-810
New two-component composite polymer films are prepared and studied in terms of thermal stability and stress-strain properties.
The matrix component of the composite is polyimide based on 3,3′,4,4′-(1,3-diphenoxybenzene)tetracarboxylic dianhydride and
4,4′-bis(4″-aminophenoxy)diphenyl sulfone. Another component is polyaniline or the copolymer poly(aniline-co-2-aminobenzoic acid). Composite films are cast from mixed solutions of individual polymers in N-methyl-2-pyrrolidone. Interpolymer interactions in polyimide composites with polyaniline or the copolymer of aniline and
2-aminobenzoic acid are investigated via viscometry and IR spectroscopy. The thermal treatment of composite films with poly(aniline-co-2-aminobenzoic acid) results in decarboxylation of the copolymer and formation of polyimide-polyaniline composite films.
The morphology, microphase structure, and porosity of the composite films are different from those of the films cast from
solutions of polyimide-polyaniline mixtures. 相似文献
13.
Yanling Wang Qiang Peng Qiufei Hou Kun Zhao Ying Liang Benlin Li 《Theoretical chemistry accounts》2011,129(2):257-270
Five fluorene-based conjugated copolymers were studied to explore the effect of acceptor on the electronic and optical properties.
Their ground-state, excited-state electronic structures and the tunable optical properties were theoretically investigated
using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The acceptors including
quinoxaline (Q), 2,1,3-benzothiadiazole (BT), thieno[3,4-b]pyrazine (TP), 2,1,3-benzooxadiazole (BO), and pyridopyrazine (PP) can significantly influence the copolymers’ electronic structures, molecular orbitals, geometric conformations, and optical
properties. Calculations were made on systems containing one, two, three, and four oligomers in the neutral, cationic, and
anionic structures, which can be extrapolated to infinite chain length polymers. The result indicated that the sequence of
the band gap was on the reverse trend of emission wavelength. The strong electron-withdrawing strength of TP unit and coplanar backbone in poly[2,7-(9,9′-dihexylfluorene)-alt-2,3-dimethyl-5,7-dithien-2-yl-thieno[3,4-b] pyrazine] resulted in the enhanced degree of intramolecular charge transfer (ICT)
and lowest band gap. The contribution of acceptors to IP was also found to follow the sequence of TP < Q < PP < BT < BO. The absorption and emission spectra exhibited red-shift with increasing the conjugation lengths. The present study suggested
that the electronic and optical properties of donor–acceptor conjugated copolymers were affected by the acceptor structure. 相似文献
14.
Yu-Peng Tian Ming-Liang Zhang Zhang-Jun Hu Han-Mei Hu Jie-Ying Wu Xuan-Jun Zhang Sheng-Yi Zhang Xu-Tang Tao Min-Hua Jiang He-Ping Chen Suchada Chantrapromma Hoong-Kun Fun 《Transition Metal Chemistry》2005,30(7):778-785
A new Schiff base 4-[N-hydroxyethyl-N-(methyl)amino]benzaldehyde S-methyl dithiocarbazate (HL, where H is a dissociable proton) and the ruthenium complex [Ru(bpy)2L]PF6 (bpy = 2,2′-bipyridine) have been synthesized. The structural determinations of the ligand and its ruthenium complex, by
X-ray crystallography, show that the ligand is coordinated as a monoanionic bidentate N, S-donor, forming a four-member chelate
ring with a bite angle of 65.91°. The complex shows intense MLCT transitions in the visible region. Fluorescent and electrochemical
properties have been also studied. The complex in DMF solution exhibited a strong two-photon absorption (t.p.a.) at 532 nm
nanosecond laser pulses. The t.p.a. coefficient β, t.p.a. cross-section σ and the third-order optical nonlinearity χ(3) of the complex and the ligand have been determined by the Z-scan technique. 相似文献
15.
A novel one-dimensional dicyanamide bridged lead(II) complex containing nitronyl nitroxide radicals, [Pb(NIT-1′-MeBzIm)(Dca)2]
n
(Dca = dicyanamide anion, NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide),
has been prepared and characterized by magnetic and single-crystal X-ray diffraction studies. In the complex, Pb2+ ion shows seven-coordinate geometry. A chain structure with single, symmetrical, end-to-end Dca bridges is found in the compound.
These units develop as 1D species, where dicyanamide ligands bridge Pb2+ ions. Otherwise, molecules are linked by π-π-piling interactions to form 2D network structure. Magnetic investigation indicates
the existence of intramolecular interactions, wich are ferromagnetic with J = 23.6 cm−1, where the spin Hamitonian is defined as H = −2Σ
i,j
J
i,j
S
i
S within the complex. 相似文献
16.
Sushanta Saha Prodyut Kumar Sarkar Ambikesh Mahapatra 《Transition Metal Chemistry》2006,31(3):389-395
The reaction between Pd(N,N′)Cl2 [N,N′ ≡ 1-alkyl-2-(arylazo)imidazole (N,N′) and picolinic acid (picH) have been studied spectrophotometrically at λ = 463 nm in MeCN at 298 K. The product is [Pd(pic)2] which has been verified by the synthesis of the pure compound from Na2[PdCl4] and picH. The kinetics of the nucleophilic substitution reaction have been studied under pseudo-first-order conditions.
The reaction proceeds in a two-step-consecutive manner (A → B → C); each step follows first order kinetics with respect to
each complex and picH where the rate equations are: Rate 1 = {k′0 + k′2[picH]0} × [Pd(N,N′)Cl2] and Rate 2 = {k′′0 + k′′2[picH]0}[Pd(N,O)(monodentate N,N′)Cl2] such that the first step second order rate constant (k′2) is greater than the second step second order rate constant (k′′2). External addition of Cl− (as LiCl) suppresses the rate. Increase in π-acidity of the N,N′ ligand, increases the rate. The reaction has been studied
at different temperatures and the activation parameters (Δ‡H° and Δ‡S°) were calculated from the Eyring plot. 相似文献
17.
Desigan Reddy Kate J. Akerman Matthew P. Akerman Deogratius Jaganyi 《Transition Metal Chemistry》2011,36(6):593-602
The substitution kinetics of the complexes [Pt(terpy)Cl]Cl·2H2O (PtL1), [Pt(tBu3terpy)Cl]ClO4 (PtL2), [Pt{4′-(2′′′-CH3-Ph)terpy}Cl]BF4 (PtL3), [Pt{4′-(2′′′-CF3-Ph)terpy}Cl]CF3SO3 (PtL4), [Pt{4′-(2′′′-CF3-Ph)-6-Ph-bipy}Cl] (PtL5) and [Pt{4′-(2′′′-CH3-Ph)-6-2′′-pyrazinyl-2,2′-bipy}Cl]CF3SO3 (PtL6) with the nucleophiles imidazole (Im), 1-methylimidazole (MIm), 1,2-dimethylimidazole (DIm), pyrazole (Pyz) and 1,2,4-triazole
(Trz) were investigated in a methanolic solution of constant ionic strength. Substitution of the chloride ligand from the metal
complexes by the nucleophiles was investigated as a function of nucleophile concentration and temperature under pseudo first-order conditions using UV/Visible and stopped-flow spectrophotometric techniques. The reactions follow the rate law
k\textobs = k2 [ \textNu ] + k - 2 k_{\text{obs}} = k_{2} \left[ {\text{Nu}} \right] + k_{ - 2} . The results indicate that changing the nature or distance of influence of the substituents on the terpy moiety affects the
π-back-donation ability of the chelate. This in turn controls the electrophilicity of the metal centre and hence its reactivity.
Electron-donating groups decrease the reactivity of the metal centre, while electron-withdrawing groups increase the reactivity.
Placing a strong σ-donor cis to the leaving group greatly decreases the reactivity of the complex, while the addition of a good π-acceptor group significantly
enhances the reactivity. The results indicate that the metal is activated differently by changing the surrounding atoms even
though they are part of a conjugated system. It is also evident that substituents in the cis position activate the metal centre differently to those in the trans position. The kinetic results are supported by DFT calculations, which show that the metal centre is less electrophilic when
a strong σ-donor is cis to the leaving group and more electrophilic when a good π-acceptor group is part of the ring moiety. The temperature dependence
studies support an associative mode of activation. An X-ray crystal structure of Pyz bound to PtL3 was obtained and confirmed
the results of the DFT calculations as to the preferred N-atom as a binding site. 相似文献
18.
Hee-Jin Ryoo Hee-Tak Kim Young-Gi Lee Jung-Ki Park Seong-In Moon 《Journal of Solid State Electrochemistry》1998,3(1):1-6
The thermal and electrochemical characteristics of plasticized polymer electrolytes composed of poly(acrylonitrile-co-methyl methacrylate) [P(AN-co-MMA)], a plasticizer [a mixture of ethylene carbonate and propylene carbonate], and LiCF3SO3 were investigated. The incorporation of a MMA unit into the matrix polymer was effective for an increase in the compatibility
between the matrix polymer and the plasticizer. The comparative investigation of the interfacial resistance of the Li/polymer
electrolyte/Li cell for the PAN-based and the P(AN-co-MMA)-based polymer electrolytes showed that the MMA unit could improve the stability of the polymer electrolyte toward the
Li electrode, which is probably due to the enhanced adhesion of the polymer electrolyte to the Li electrode.
Received: 14 July 1997 / Accepted: 14 May 1998 相似文献
19.
A series of novel fluorinated poly(ether ketone amide)s (PEKAs) were prepared from an unsymmetrical aromatic diamine, (4′-(4″-amino-2″-trifluoromethylphenoxy)-3′,5′-dimethylphenyl)(4-aminophenyl)-methanone
(1), with various aromatic dicarboxylic acids using the phosphorylation polycondensation technique. The PEKAs had inherent viscosities
ranging from 0.43 to 0.65 dl/g. All the fluorinated PEKAs could be soluble in many polar organic solvents such as N-methyl-2-pyrrolidinone (NMP), N,N′-dimethylacetamide (DMAc), N,N′-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and tetrahydrofuran (THF). Flexible and tough polymer films could be
prepared by casting from DMAc solvent. The PEKA films exhibited high optical transparency with a cutoff wavelength of 354–365 nm
and good mechanical properties with tensile strengths of 78–98 MPa and elongations at break of 11.5–18.5%. They showed glass-transition
temperatures in the range of 288−323 °C and the onset decomposition temperatures in the range of 450−461 °C in nitrogen atmosphere.
Meanwhile, the PEKA films possessed low dielectric constants of 1.98–2.71 at 1 MHz and low moisture absorption (<2%). Due
to their properties, the fluorinated PEKAs could be considered as photoelectric and microelectronic materials. 相似文献
20.
In the compound [Ni(Bptc)2(Bimb)2(H2O)2] (I), where H4Bptc is 3,3′,4,4′-biphenyltetracarboxylic acid; Bimb is 4,4′-bis(1-imidazolyl)biphenyl), Ni(II) has a distorted octahedral coordination geometry, which was bonded with two N atoms from two
Bimb ligands, two O atoms from two H2Bptc2− ligands and two water O atoms. The crystal structure of compound I is stabilized by the π-π-stacking and hydrogen bonds interaction. 相似文献