聚硅烷高分子对烯类单体的光敏聚合作用

<正> 可溶性聚硅烷高分子(polysilane polymer)是80年代初期才发展起来的一种功能高分子,有关文献对于聚硅烷高分子的紫外光解及光刻作用有较详细的报道,然而有关它的光敏引发聚合作用则鲜有报道。我们研究了聚硅烷高分子对苯乙烯的光敏引发聚合作用及其特点,这对于开发一类新的高分子光敏剂有重要的意义。     

聚硅烷研究进展：（Ⅱ）聚硅烷的电子结构与电子光谱特性

聚硅烷的独特性质与其电子在主链上离域有密切关系，本文就聚硅烷的电子结构及电子光谱特性的研究作一综述。     

聚硅烷高分子化学的发展及应用

本文介绍了聚硅高分子的合成方法、紫外吸收、光敏性、导电性等一系列特殊性质,聚硅烷高分子的化学反应以及聚硅烷材料的应用.     

Oxygen-crosslinked polysilane: the new class of Si-related material for electroluminescent devices

The preparation and optical properties of the novel silicon-related material named oxygen-crosslinked polysilane were investigated. The oxygen-crosslinked polysilane was prepared by the thermal annealing of the precursor polysilane bearing alkoxyl groups. The photoluminescence consisting of a broad visible band at about 440 nm and a relatively sharp band at about 360 nm was observed at room temperature. The relative intensities of the visible emission were changed during the crosslinking. The visible emission was greatly affected by the steric hindrance of the alkoxyl groups of the precursor. The visible electroluminescene (EL) was also observed uniformly from the EL cell consisting of the oxygen-crosslinked polysilane film sandwiched between A1 electrode and indium-tin-oxide (ITO) electrode. The current densities of the EL cell increased with an increase in the oxygen-crosslinking. © 1997 John Wiley & Sons, Ltd.     

一种超支化聚硅烷的合成和性能

近年来,光电高分子的研究由于其在发光二极管、太阳能电池、光信息材料、传感器等方面的潜在应用而得到了广泛重视[1].自从英国剑桥大学Cavendish实验室的Burroughes等首次发现聚对亚苯基亚乙烯基的电致发光现象以来[2],共轭聚合物作为发光材料的研究迅速引起了人们的注意[3~5]     

Photoelectrical properties of Langmuir–Blodgett films of poly(methyl phenylsilane)s

Langmuir–Blodgett (LB) films were prepared from poly(methylphenylsilane) bearing electron acceptor π-conjugated substituents. The small limiting area (0.078 nm²) per one repeating unit of polysilane (PSi) in monomolecular film and the large thickness of the film (6 nm) suggest that the polymer chains are not fully spread on water surface. The electrical and photoelectrical properties of Al/LB film/Au sandwich cells containing various numbers of the polysilane layers were studied. Holes were transported from the Al electrode through the LB film to the Au electrode when the light was absorbed by the polysilane. The highest photovoltaic effect occurred in the first monolayer of polysilane at the Al contact. The cell resistivity and the photovoltage were decreased by parallel conductance of defects in the films consisting of small numbers of PSi layers.     

含多苯(基)苯基的硅-硅键化合物的研究

以YMeSiCl_2(Y=-)为原料,在金属Na存在下,制备了(YMeSi)均聚物和(YMeSi)(RMeSi)(R=CH_3、CH=CH_2、Ph)、(YMeSi)(PhMeSi)(Me_2Si)、(YMeSi)(PhMeSi)(CH_3=CHMeSi)(Me_2Si)_q等一些线型聚硅烷.某些线型聚硅烷与几种电子受体形成电荷转移复合物.对其中化合物作了光谱分析,测定了它们的分子量和导电性.     

液体聚硅烷的合成与交联

采用具有不同有机取代基的二氯硅烷与甲基二苯基氯硅烷为原料,在甲苯中以金属钠共缩合的方法,合成了可流动的聚硅烷。这些聚硅烷可用灌注、浇铸、涂敷等方法制成各种形状,并能在多乙烯基硅烷存在下,以紫外光辐照进行交联。本文还讨论了这些聚硅烷的分子量分布以及红外、紫外、核磁共振等光谱性质。     

Quantum‐chemical approach to the solvatochromic transition in polysilane derivatives

We approached the solvatochromic transition observed in polysilane derivatives (poly[bis(4‐propoxybutyl)silylene] (PPBS)) from the standpoint of various quantum chemical treatments. It was found from conventional geometry optimizations at the levels of semiempirical and ab initio molecular orbital methods that a protonation to polysilane oligomers with side chain R = ? OCH₃ results in the conformational change of Si‐backbone to a trans‐zigzag structure. Using the Elongation method, which was developed for efficient calculations of huge systems, it was demonstrated that a protonation could change the conformation of Si‐backbone to a trans‐zigzag structure over 10–14 Si atoms. In addition, ab initio calculations showed that the positive charge of a proton can delocalize into the Si‐backbone through a long side chain in PPBS. Positively charged polysilane oligomers provide a rotational barrier that prefers a trans‐zigzag structure, whereas neutral oligomers have a barrier that results to a random structure. This unique behavior of the charged polysilane oligomers should not be disregarded in understanding the mechanism of the solvatochromic transition in PPBS. In ab initio configuration interaction/Mφller‐Plesset through‐space/bond interaction analysis, it was found that such a unique behavior of the rotational barrier in polysilane oligomers could be explained by the effect of orbital delocalization through σ‐conjugation on the Si‐backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 119–133, 2006     

Block interrupt polysilane derivatives

High molecular weight block interrupt polysilane derivatives have been prepared by the condensation of a number of α,ω-dichloropolysilanes with some aromatic bis silanols. In this manner, polymers containing polysilane blocks of 2, 4, or 6 catenated silicon atoms have been prepared. The materials are thermally stable and the UV spectroscopic properties mimic those of the corresponding monomers. Although these materials bleach upon irradiation in the deep UV, surprisingly, the block interrupt polysilanes behave as negative resists upon exposure to 254 nm radiation. This behavior contrasts with that of standard polysilane homopolymers which usually function in a positive lithographic mode.     

Block interrupt polysilane derivatives

High molecular weight block interrupt polysilane derivatives have been prepared by the condensation of a number of α,ω-dichloropolysilanes with some aromatic bis silanols. In this manner, polymers containing polysilane blocks of 2, 4, or 6 catenated silicon atoms have been prepared. The materials are thermally stable and the UV spectroscopic properties mimic those of the corresponding monomers. Although these materials bleach upon irradiation in the deep UV, surprisingly, the block interrupt polysilanes behave as negative resists upon exposure to 254 nm radiation. This behavior contrasts with that of standard polysilane homopolymers which usually function in a positive lithographic mode.     

A ladder polysilane wrapped with amylose

A mixture of tricyclic ladder polysilane 1 and amylose, upon pH adjustment of aqueous media from very basic to neutral, affords a supramolecular complex in which a preferential twisted (helical) conformation is induced on the ladder polysilane to display optical activity. Under the experimental conditions used, 1 assumes a left-handed twisted structure in the left-handed helical channel of amylose.     

硅取代聚烷硅的合成与表征

硅取代聚烷硅的合成与表征;聚甲基硅烷;高分子反应     

Photoinitiation of vinyl polymerization by polysilanes

Polysilanes were found to photoinitiate the polymerization of a variety of vinyl monomers including methyl methacrylate, styrene, ethyl acrylate and acrylic acid. Polymerization initiated by polysilane photolysis is rather insensitive to oxygen inhibition, which may make it especially suitable for polymerization of thin films. The initiation efficiency of poly(phenylmethylsilylene) in styrene was determined from dilatometry data to be 1 × 10^?3. This rather low efficiency is counterbalanced by the very high extinction coefficient of polysilane polymers, ca. 4–8 × 10³ per silicon atom. Possible reasons for the low initiation efficiency and reduced oxygen inhibition of polysilane photoinitiators are discussed.     

Thermo-driven chiroptical switching polysilane featuring 2-cyclopentylethyl side group

A new rod-like helical polysilane, poly{(S)-3,7-dimethyloctyl-(2-cyclopentylethyl)silane}, was found to undergo a thermo-driven, helix-helix transition at –33 ° C in isooctane associated with the discontinuous changes in the Si -Si *transition energy and intensity in the transition temperature region. This is the first example of a helix-helix transition polysilane with a cycloalkyl group. A similar rod-like polysilane derivative, poly{(S)-3,7-dimethyloctyl-(1-cyclopentylmethyl)silane}, however, did not undergo any helix-helix transition between –61 and 80 ° C.     

Development of microchannel reactors using polysilane-supported palladium catalytic systems in capillaries

A new method of immobilizing Pd catalysts on the channel wall of a capillary by using polysilane with metal oxide has been developed, and applied to hydrogenation reactions.     

链状聚硅烷的导电性质和电子状态

本文讨论了链状聚硅烷的导电性质，简要介绍了关于该聚合物的电子状态的一些理论研究结果，以此解释了链状聚硅烷的导电性质。     

Polysilane spherulites and their high photoluminescence quantum yields

Large polysilane spherulites have been observed. The spherulites were prepared by controlling the removal rate of solvents from poly(n-butyl-n-pentylsilane) under a xylene atmosphere. The diameter of the spherulites was greater than 0.1 mm. The structure of the spherulites was compared with that of the polysilane powder by polarized microscopy, SEM, DSC, and x-ray diffractometry. A high photoluminescence quantum yield of 0.3 was obtained for the spherulites. © 1997 John Wiley & Sons, Inc.     

Achiral Polydialkylsilane Aggregates That Record Stirring Direction

Achiral polysilane aggregates can recognize the chirality of low‐molecular‐weight compounds. It was found that they can also record the stirring direction. Poly(n‐decyl‐2‐methylpropylsilane), poly(n‐nonyl‐2‐methylpropylsilane), poly(n‐decyl‐2‐ethylbutylsilane), and poly(n‐decyl‐(S)‐2‐methylbutylsilane) aggregates were prepared in a mixture of tetrahydrofuran/isopropanol. Although the optical activity of the aggregates of the polysilane with chiral side chains was not tunable by changing the direction of the vortex flow, that of the aggregates of the optically inactive polysilane had a strong relationship to the direction, time, and rate of the vortex flow. The chiral stacked polysilanes were proposed to exist at the surfaces of the aggregates. The optically inactive polysilanes also exhibited optical activity under shear force with a distinct signal in the linear dichroism (LD) spectra of the achiral aggregates in vortex flows. However, the LD signals did not have a significant influence on the circular dichroism signals.     

Structurally and conformationally defined small methyl polysilanes

Possessing the property of sigma-bond electron delocalisation, polysilanes are a class of compounds with unique properties. In recent years major progress has been achieved in the theoretical understanding and the synthesis of polysilanes. Much insight into the connection between conformation and electronic properties has been gained from studies of defined small polysilane molecules. The transition from Wurtz type coupling reactions to the stepwise construction of polysilane molecules employing silyl anions as key intermediates has permitted access to defined compounds with a higher degree of structural complexity. Besides this, several methods have been developed to control the conformational properties and thus gain control over the electronic properties of polysilanes.