一类新型取代乙炔化合物的合成及表征

用二环己基碳酰亚胺(DCC)和N,N-二甲基吡啶(DMAP)催化法合成了系列功能取代乙炔;与酸催化等法进行比较,DCC／DMAP催化法具有反应条件温和、产率高的优点;用元素分析,IR,^1H NMR和DSC等对它们的结构进行了表征和确认。     

POLYCYCLOTRIMERIZATION OF DIYNES,A NEW APPROACH TO HYPERBRANCHED POLYPHENYLENES*

Polycyclotrimerization of diynes was explored as a new route to hyperbranched polymers in thisinvestigation. Polymerization of terminal diynes of 1,8-nonadiyne and 1,9-decadiyne was studied usingTaCl_5, NbCl_5, Mo(CO)_4(nbd) and [Mo(CO)_3cp]_2 as catalysts (where nbd = 2,5-norbornadiene, cp = cyclo-pentadiene). A soluble polymer was obtained when the polymerization of 1.9-decadiyne was initiated byTaCl_5 at low temperature (0℃). The polymer, however, became partially soluble after purification, possiblydue to the postpolymerization-induced crosslinking. NbCl_5-catalyzed polymerization of 1,9-bis(trimethylsilyl)-1,8-nonadiyne gave a completely soluble polymer. Soluble polymers were also obtainedfrom the polymerization of 3,9-dodecadiyne initiated by NbCl_5, Mo(CO)_4(nbd), [Mo(CO)_3cp]_2, PdCl_2-ClSiMe_3 and Pd/C-ClSiMe_3. IR, UV, and NMR spectroscopic analysis revealed that different catalysts gavepolymers with different structures, ranging from linear polyenes to hyperbranched polyphenylenes. Thepolymers absorb UV light at around 250 nm and emit fluorescence at 340 nm when they are excited at 248nm.     

SYNTHESIS,CHARACTERIZATION AND OPTICAL PROPERTIES OF THE COPOLYMERS OF C_(60) AND 1-PHENYL-1-PROPYNE*

While WCl_6-Ph_4Sn fails to polymerize 1-phenyl-1-propyne (PP) at room temperature, highmolecular weight (M_w up to 410×10~3) polymers are obtained in high yields (up to 80%) when thepolymerizations of PP are carried out in the presence of C_(60) using the W catalyst under the same conditions.The polymers are soluble in common organic solvents such as THF, chloroform, and toluene. Molecularstructures of the polymers are characterized by FT-IR, UV, NMR, GPC and XRD, and it is found that C_(60) iscopolymerized with PP. Thus C_(60) plays the dual roles of comonomer and cocatalyst in the polymerizationreaction. C_(60) contents of the copolymers can be easily changed by varying the C_(60) amounts in the feedmixtures. The copolymers effectively limit strong 532 nm laser pulses, whose limiting performance issuperior to that of parent C_(60).     

HYPERBRANCHED CONJUGATIVE MACROMOLECULES CONSTRUCTED FROM TRIPLE-BOND BUILDING BLOCKS

Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights(up to 1×10~6)in high yields(up to 99.9%).The polymers possess low intrinsic viscosities and high thermal stabilities,losing little of their weights when heated to＞400℃.Upon pyrolysis at＞800℃,the polymers graphitize with high char yields(up to 86%).Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C_(60),a well-known optical lirniter.Poly(alkenephenylenes),poly(aroylarylenes)and polyynes are readily cross-linkable by UV irradiation,serving as excellent photoresist materials for the generation of patterns with nanometer resolution.Thin films of hyperbranched polyynes exhibit very high refractive indexes(n up to 1.86).The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls,which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities(M_s up to ca.118 emu/g)and near-zero magnetic losses.     

Bt玉米中微量元素锂、硒、钼、铬含量测定

随着转基因食品的推广应用,人们越来越关心其食用安全性。以转Bt基因玉米及其亲本为实验材料,借助于ICP-MS对其中人体必需的微量元素锂、硒、钼和铬进行了测定。结果显示,外源基因的整合导致了锂、硒、钼和铬含量减少,这对玉米的营养价值非常不利;特别是转Bt基因玉米中硒和钼,成倍减少。这些结果说明转基因技术如果控制不严可能会对玉米的食用安全性产生不良影响,转基因植物的推广应用应当严格审查。转Bt基因玉米吸收上述微量元素减少的原因尚需进一步研究。     

新型超支化聚芳烃的合成与性能研究

3,6-二乙炔基-9-(三苯胺基)-咔唑、4,4′-二乙炔基-4″-(咔唑基)-三苯胺双炔和1-辛炔单炔在CpCo(CO)2-hν催化的条件下合成了新型超支化聚芳烃.所得的聚合物都溶于普通溶剂(甲苯、THF、氯仿、二氯甲烷等).在光激发的条件下,聚合物在428 nm左右发射蓝光,其荧光量子效率达到62%.所有超支化聚合物都表现出优异的热稳定性,它们的起始分解温度高达484℃.     

Formation of Self-organization InAs Quantum Dots on (001) InP Substrate by As/P Exchange Reaction in MOCVD

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5-[4'-正庚基-氧-联苯基-4-氧-羰基]基-1-正戊炔的晶体结构研究

由于共轭聚合物的光致发光和电致发光性能, 有望成为制造全塑性发光二极管的材料, 因此近年来已引起人们的研究兴趣[1]. 聚乙炔是一种典型的共轭聚合物, 其不稳定性和难加工性限制了它的应用. 而含联苯液晶基元的取代聚乙炔, 不仅其难加工性得到了改善, 提高了稳定性, 而且赋予了聚合物液晶性, 因此有望开发出一批新型的高性能材料[2]. 目前对这类新型取代乙炔聚合物及其单体的凝聚态结构的报道还较少. 本文通过WAXD, TEM和AFM等手段对小分子液晶5-[4′-正庚基-氧-联苯基-4-氧-羰基]基-1-正戊炔(A3E′O7)的晶体结构进行了研究.     

SYNTHESIS AND PROPERTIES OF POLY(AROMATIC DIACETYLENE)S CONTAINING FLUORENE

Novel fluorene-based poly(aromatic diacetylene)s have been synthesized by CuCl-catalyzed oxidative coupling of aromatic diynes.New aromatic diynes 2,7-diethynyl-9,9-bis(triphenylamine)fluorene(M_1)is synthesized by multistep reactions.The structures and properties of the polymers are characterized and evaluated by IR,NMR,TGA,UV, photoluminescence(PL),and cyclic voltammetry analyses.These polymers possess good thermal stability.All the polymers are completely soluble in coammon solvents such as toluene,TH...     

SYNTHESIS, HELICITY, AND BIOLOGICAL PROPERTIES OF MONOSACCHARIDE-CONTAINING POLY（PHENYLACETYLENE）S

Poly（phenylacetylene）s beating monosaccharide pendant groups are synthesized in high yields by [Rh（nbd）Cl]2 catalyst. The polymers have high molecular weights and give satisfactory spectroscopic data corresponding to their molecular structures. They are thermally quite stable （≥ 300℃） and show strong circular dichroism signals in the visible spectral region owing to the helicity of the polyene backbone. The monosaccharide-containing polyacetylenes are cytophilic and can stimulate the growth of living cells.