STUDIES ON THE STRUCTURE OF FORKED CONJUGATIVE SYSTEMS——THE CONFORMATION OF 3-ACETYL-8-PHENYL-3,5,7-OCTATRIENONE-2

The conformational properties of the title molecule in the isolated state have been investigated by the PCILO method and compared with those found from X-ray crystallographic determination. The results indicate that, in this type of forked conjugative series, because of steric hindrance, only one branch of the forking groups is basically coplanar with the conjugated trunk chain and plays the role of a terminal group, while the other one is not coplanar with the conjugated trunk chain and acts as an ordinary substitutent. Referring to the phenyl group, the acetyl group on the different sides of ethylenic chain exhibits the properties of a terminal group.     

STRUCTURAL BASES FOR DOUBLE ABSORPTION PEAKS OF SOME AROMATIC HETEROCYCLIC PHENYL KETONES

In order that the structural bases for the double absorption peaks of aromatic heterocyclic phenyl ketones may be distinguished, three pairs of forked conjugative systems (Ⅰ, Ⅱ, Ⅲ) have been investigated by means of the rule of homologous linearity, For each pair of these series the two homologous lines have been found to pass through or to come very close to the position for the double peaks. According to the relative position of a homologous line and the location of its starting point, each of the double peaks may be assigned to the homologous series to which it should belong. Thus it provides a reliable and quantitative method for the determination of the structural basis for each of the double peaks. By applying the method of similar triangles between homologous lines as described previously, the equivalent △N_s values for the phenyl, thienyl, furyl and pyrryl groups attached directly to the carbonyl group have been calculated. This indicates that these groups all play the role of a substituent i     

Effect of the position of substitution on the electronic properties of nitrophenyl derivatives of fulleropyrrolidines:Fundamental understanding toward raising LUMO energy of fullerene electron-acceptor

A series of substituted para-, meta- and ortho-nitrophenyl derivatives of fulleropyrrolidine were synthesized to investigate the effects of the position of substitution on electronic properties by using steady-state absorption and fluorescence spectra, combined with DFT calculations. The results confirmed that the position of substitution has little effect on absorption and fluorescence spectra, whereas a significant effect was observed on their LUMO energy levels. The theoretical calculations revealed that the LUMO energy of the ortho-nitrophenyl substituted derivative was increased 0.1 eV above those ofpara- and meta-substitution. The prominent effect ofortho-substitution was attributed to the through-space orbital interaction between spatially closed electron-withdrawing nitro group and fullerene cage. These findings could provide fundamental insights in raising LUMO levels of C6o-based electron acceptor materials and an alternative strategy to increase open circuit voltage Voc in polymer solar cells.     

HeI photoelectron spectroscopic (PES) studies of the electronic structure in ω-heterocycle a-cyano polyenic ethyl ester compounds

HeI photoelectron spectra of w-heterocycle a-cyano polyenic ethyl ester compounds (1-6) have been given in this paper. Assignment of the spectra is also done with the aid of HeI photoelectron spectroscopic (PES) results of smaller molecules which have similar atomic group to the molecules studied, and the aid of MNDO molecules orbital calculations. The lowest PES experimental ionization potentials (IPs in eV) of different molecules reduce gradually with the increasing number of ethylenic group. The -CO2C2H5 group can be only considered as a substituent.     

THE CALCULATION OF CHEMICAL SHIFTS IN DISUBSTITUTED NAPHTHALENES

<正> The principle and method for calculating the chemical shifts of substituted benzenes have been extended to the calculation of chemical shifts in disubstituted naphthalenes. We have set up a series of empirical parameters for the calculation of chemical shifts. The calculated results of 439 8 values from 78 compounds show that the standard deviation between the calculated and the experimental values is 0.08 ppm. The combination of this calculation with that of the coupling constants can be used to provide a criterion .for the determination of molecular structure in disubstituted naphthalenes as well as to assign NMR parameters for the experiment of proton simulated spectra of disubstituted naphthalenes.     

INTERACTION OF WALSH- AND π-ORBITALS——PHOTOELECTRON SPECTRA OF CYCLOPROPYL SUBSTITUTED BENZENES

In this paper the photoelectron spectra of a series of cyclopropyl substituted benzenes arerecorded and discussed. Although their interpretation is made difficult by conformational pro-blems, with the possible exception of hexacyclopropyl benzene (12), it is confirmed that theWalsh orbitals of the cyclopropyl group interact appreciably with the π-system to which theyare attached in both the bisected and perpendicular conformation. The ratio of the cross-terms is B(eA, 2p)/B(es,2p)≈1.4 rather than a much larger number suggested by thetraditional diagrams for the Walsh orbitals. It is shown that a representation, in terms ofof localized bond orbitals derived from an STO-3G model, is more appropriate and heuristi-cally useful.     

PREPARATION AND FLUORESCENT PROPERTIES OF Eu~(3+)-CONTAINING CORE-SHELL NANOPARTICLES

By using a two-stage soapless emulsion polymerization, four kinds of core-shell nanoparticles have been prepared,which are composed of a polystyrene core having an average diameter of 256 nm and a poly(methyl methacrylate-co-acrylicacid) shell. The transmission electron microscopy (TEM) micrographs and the atomic force microscopy (AFM) imagesevidenced the presence of a core-shell structure. In the infrared spectra, the shift of v_(COOH) to lower wavenumber withincreasing Eu~(3 ) ion content indicates that coordination between the oxygen of the carboxylic group and Eu~(3 ) has occurred.The fluorescence intensity of ~5D_0-~7F_2 transition was observed to reach its maximum with a carboxyl group molar percentageof 40% in the shell and an Eu~(3 )/--COO~- molar ratio of 1:3. The fluorescence intensity ratio of ~5D_0-~7F_2 to ~5D_0-~7F_1 transition reached its maximum with an Eu~(3 )/--COO~- molar ratio of 1:3 for all the four series.     

THE CALCULATIOM OF CHEMXCAL SHIFTS IN SUBSTITOTED PYRIDINES

<正> The principle and method for the calculation of chemical shifts of substituted benzenes have been extended to calculation of the cheiiical shifts in substituted pyridines. We have set up a series of empirical parameters for calculation of the chemical shifts. The calculated results of 154 δ values frou 54 compounds show that the standard deviation between the calculated and the experimental values is 0 . 09 ppm. The combination of the coupling constants can be used to provide a criterion for the determination of molecular structure in substituted pyridines and to assign NMR parameters for the experiment of proton simulated spectra of substituted pyridines.     

Studies on the Binding Mode of Pinacyanol Chloride to Nucleic Acids

The interaction of pinacyanol chloride(PC) with nucleic acids has been investigated by a series of experiments.Extensive hypochromism,appreciable peak shifts,isosbestic points and new peaks of the product of binding to nucleic acids in the spectra were observed.They showed that the interaction between PC and nucleic acids occurred.The results from absorption spectra of DNA,DNA melting,electrophoresis and fluorescence polarization studies have indicated that PC binds to DNA in nonintercalative way.Consistent with the nonintercalation,the studies of fluorescence titration and absorption titration specified that the binding of PC to nucleic acids occurred by an outside stacking binding,in which nucleic acids served for acting templates,The fact that the new absorption peaks of bound PC at ca,485nm are just close to the absorption bands of Haggregate of PC at high concentrations without DNA further supports the outside stacking binding mode,In addition,other evidence indicated that the interaction between PC and nucleic acids is not purely electrostatic.     

AN ANOMALOUS MOSSBAUER SPECTRUM OF SCHORLOMITE

The characteristics of Mossbauer spectra for a sample of schorlomite are described in this paper. There are 7 fitting doublets, three of which are considered as anomalous absorptions and their origin may come front complex electronic processes occurring in the schor]omite. It has been found that the isomer shift (IS) of Fe~(3 ) exhibits an apparent temperature effectin the mineral studied.     

Zinc Porphyrin Sensitizers Containing Different Withdrawing and Donating Groups for Dye-sensitized Solar Cells: Design,Synthesis and Photovoltaic Properties

In this work, a series of unsymmetrical push-pull type zinc-porphyrins, in which meso-substituted porphyrin core bears an electron-donating group and an electron-withdrawing group in the trans positions, have been designed and synthesized to improve the light-harvesting in dye-sensitized solar cells(DSSCs). The electronic structures of these zinc-porphyrin dyes were firstly screened by using density functional theory(DFT) and time-dependent density functional theory(TDDFT) calculations. Among these zinc-porphyrin derivatives, zinc porphyrins bearing a phenyl, diphenyl-benzenamine or 3-nitro-benzoic acid substituent, denoted D1, D2 or D3, respectively, are found to exhibit superior HOMO and LUMO locations which are suitable for DSSCs systems. In particular, the η value of the DSSCs(D2) improved up to 2.3 times when compared with reference cell(D1) on account of the increase of Jsc, FF and Voc. The enhancement of cell performance arises from the effective charge separation and decreases the aggregation of porphyrin dyes.     

Theoretical Study on the Structural and Optoelectronic Properties of the Linear Perfluorooctane Sulfonate （PFOS）

The perfluoroalkyl substances(PFS) have attracted considerable attention in recent years as a persistent global pollutant to be able to bioaccumulate in higher organisms.In this paper,theoretical analysis on electronic structures,optoelectronic properties and absorption spectra properties of the perflurooctane sulfonate(PFOS) in gas phase have been investigated by using the DFT/TD-DFT method.The geometric structures,electrostatic potentials,energy gaps,ionization potentials,electron affinities,frontier molecular orbital,excitation energies and absorption spectra for the ground state of PFOS were calculated.The result indicates that the ability of accepting electron of neutral PFOS is larger than that of anionic PFOS,while the electron excited by UV irradiation from HOMO to LUMO in the anionic PFOS is easier than that in the neutral PFOS.     

Density Functional Theory Study on Organic Dye Sensitizers Containing Bis-dimethylfluorenyl Amino Benzofuran

The geometries, electronic structures, polarizabilities and hyperpolarizabilities, as well as the UV-Vis spectra of the two organic dye sensitizers containing bis-dimethylfluorenyl amino benzofuran were studied via density functional theory （DFT） and time-dependent DFT. The features of electronic absorption spectra were assigned on account of the agreement between the experiment and the calculations. The absorption bands in visible region are related to photoinduced electron transfer processes, and the dimethylfluorenyl amino benzo[b]furan groups are major chromophore that contributed to the sensitization of photo-to-current conversion. The role of vinylene group in geometry, electronic structure and spectra property is analyzed according to the comparative study of the dyes.     

用于制备聚氨酯纳米复合物的高岭石粒子的表征

Clay such as kaolinite， is commonly used as an additive to modify the thermal properties of polymer. In this paper， the morphology， composition， shape and structure of kaolinite was characterized by various advanced techniques. The TEM/ EDX data showed that the kaolinite had a larger particle size and a Si/Al ratio of 1.8. The individual particle of kaolinite was a single crystalline. TEM also showed that these particles were always stacked together due to the presence of electrostatic cohesive energy and hydrogen bond between plaletes. The PAS-FTIR spectra showed that no absorbance of hydroxyl group for hydration water in hydrogen bond region or at 1650cm^-1 was observed at room temperature. It meant a little ability to adsorb water for kaolinite particle. Kaolinite clay also showed no change for its PAS-FTIR spectra with increasing temperature. The TGA results revealed that kaolinite almost doesn′t lose weight at 60℃ due to loss of dehydration of absorbed water， however， it will decomposed around 510℃ and lose its hydroxyl functional group in the form of water (dehydroxylation). The result is consistent with that of PAS-FTIR analysis. This suggests that the structural hydroxyl group on the surface of individual kaolinite clay particle is very stable below 500℃， and the kaolinite composed polymer could be got by the reaction of its stable structural hydroxyl group with isocynate group of polyurethane prepolymer.     

Preparation and Characterization of Aromatic Polybenzoxazoles Copolymers Containing 2,6-Naphthalene Units

A series of polybenzoxazoles(co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4,6-diaminorescinol dihydrochloride, terephthalic acid (TA) and 2,6-naphthalene dicarboxylic acid(NDA). All of the polymers show lyotropic liquid crystal behavior in polyphosphoric acid (PPA) and methanesulfonic acid (MSA). The polybenzoxazoles exhibit an excellent thermal resistance although the crankshaft monomer has been introduced into the polymer backbone. The temperature for the 5% weight loss of all the polymers is above 600 ℃. The X-ray diffraction analysis results show that the series of the polymers has a high crystallinity. The introduction of NDA makes a slight decrease in the thermal resistance of the polymers. The maximum absorption peak in the UV-Vis spectra can be adjusted according to the amount of 2,6-naphthalene units in the polymers, which indicates the potential application of the polymers as optoelectrie materials.     

Chemical Dynamics Simulations of the Hydroxyl Radical Reaction with Ethene

We present a theoretical study of the reaction of the hydroxyl radical with ethene using electronic structure calculations and direct-dynamics simulations. High-accuracy electronic structure calculations at the CCSD（T）/aug-cc-pVTZ//MP2/aug-ce-pVDZ level have been carried out to characterize the representative regions of the potential energy surface of various reaction pathways, including OH-addition and H-abstraction. These ab initio calculations have been employed to derive an improved set of parameters for the MSINDO semiempirieal Hamiltonian specific to the OH＋C2H4 reaction. The specific-reaction-parameter Hamilto- nian captures the ab initio data accurately, and has been used to perform direct quasiclassica] trajectory simulations of the OH＋C2H4 reaction at collision energies in the range of 2-10 kcal/mol. The calculated cross sections reveal that the OH-addition reaction domi- nates at all energies over H-abstraction. In addition, the excitation function of addition is reminiscent of a barrierless capture process, while that for abstraction corresponds to an activated one, and these trends can be connected to the transition-state energies of both reactions. We note that the development of an accurate semiempirical Hamiltonian for the OH＋C2H4 reaction in this work required the inclusion of empirical dispersion corrections, which will be important in future applications for which long-range intermoleeular attraction becomes significant.     

Theoretical Studies on Structures,Stabilities, NMR Spectra and Designing Methods of Dihedral Fullerenes of C3 Series

Using bowl shaped carbon intermediates to construct dihedral fullerenes is an advisable method. Assu- ming that cap shaped C21 extends the size through building pentagons and hexagons at the U and V clefts of the brims, a series of homologous carbon intermediates was generated, in which most of the members have been unknown up to now. The joins between these homologous intermediates gave the C3 dihedral series under the restriction of C3 sym- metrical axis. The investigations point out that the stabilities of these fullerenes not only relate to the shapes of cages and the co-planarities of polygons, but also associate with the equalizations of bond lengths and the pentagonal dis- tributions. The stabilities reveal that the pentagonal distribution in cages is not negligible to the Jr delocalization, be- sides the co-planarities of hexagons and pentagons. Analyzing the possible Stone-Wales（SW） rearrangements in those fullerenes with dehydrogenated pyracyclene units（DPUs） can help us to find out the highly stable isomers. Based on the geometrical optimizations, the calculations provided the theoretical chemical shifts of unknown fullerenes and the data reconfirmed the existence of members C78 and C84. The symmetry adaptation analyses for the frontier orbitals support the formative mechanism of consecutive pentagonal and hexagonal fusions, but the simulated routes are more complicated than the pentagon road（PR） mechanism, which include not only C2 but also C3 additive reactions.     

Synthesis and Characterization of Fluoro- and Chloro- bimetallic Alkoxides as Precursors for Luminescent Metal Oxide Materials via Sol-Gel Technique

Heterobimetallic alkoxides are broadly recognized as versatile precursors for luminescence materials, and efforts are being made to develop novel routes by applying the concept of geometrical molecular design, for their synthesis and to design a single source precursor suited to photoluminescent materials. Novel and new series of bimetallic alkoxides has been prepared by metathesis route. They exhibit a lower sensitivity towards hydrolysis and so they are easier to handle as compared to other alkoxides. All the compounds were characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopies. FT-IR revealed that the molecular structure of these metal alkoxides was retained to a large extent in 4 ： 1 halogenated alcohol-benzene solution. The heteronuclear NMR spectroscopy provided useful information about chemical shifts for better understanding the likely structure based on interactions with their coordinate metals. The mass spectra show similar types of fragmentation pattern. SEM-EDS analyses showed consistency with the formulation. XRD patterns show an enhanced homogeneity at high temperature. TGA measurements show that thermal decomposition occured in steps that depended entirely on the chemical compositions and the synthesis routes. SEM observation reveals that the morphology and particle size strongly depend on synthesis routes for their precursors.     

Biocompatibility of a PDMS-coated micro-device: Bladder volume monitoring sensor

We evaluated the biocompatibility of a dimethylpolysiloxane-coated micro-device which had been designed for monitoring real-time bladder volume in previous studies.The extract assay with dimethylpolysiloxane which had been used for coating the micro-device to measure the bladder volume was performed as an in vitro cytotoxicity test.For in vivo biocompatibility testing,the inflammatory responses around the implantation site of the micro-device in subcutaneous tissue of rat were assessed by light microscope with H&E stain and fluorescence microscope with ED1 stain and von Willebrand factor stain.The averages of cell viability in dimethylpolysiloxane group were 84.6%and 82.3%at 24 h and 72 h incubation, respectively.The qualitative evaluations with light and fluorescence microscope revealed that the inflammatory changes peaked during 2 weeks but almost disappeared at 4 weeks after implantation of devices.The quantitative evaluations for granulation layer formation and neovascularization showed that the thickness of the layer in dimethylpolysiloxane group peaked during 2 weeks but it came to be stabilized at 4 weeks as thin as at 2 weeks in control group,and the frequency of neovascularization was higher in dimethylpolysiloxane group than in control group but it was not increased with time.The dimethylpolysiloxane-coated micro-device is thought be a reliable bio-medical device.     

PHOTOPHYSICAL STUDY OF SULFONATED POLYSTYRENE

The photophysical properties of a series of sulfonated micromolecule(paratoluenesulfonic acid,HPTS) and macromolecules (linear and crosslinked poiys.tvrene) have been studied by steady-state fluorescence spectra. The results indicate that the ground sulfonated ring associations can form in both the micromolecules and the macromolecules. The fluorescence spectra of the sulfonated crosslinked copolymers appear a red-shift when the copolymers change from hydrogen-type to sodium-t~pe, and some new emission bands appear in the long-wavelength region.These results are explained in terms of synergetic effect of hydrogen bond, π-π interaction and crosslinking effect.