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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2012/12/18,#,能提供电子云的分子或原子团称为路易斯碱,。,路易斯碱,即电子给予体，是在酸碱电子理论定义下的碱，指可以提供电子对的分子或离子。任何在键结轨道中有孤对电子的分子均为路易斯碱,。,此处,碱的定义和阿累尼乌斯对碱的定义不同，因此路易斯碱溶在水中不一定会产生氢氧根离子。氢键,X-HY,中的电子给予体,Y,是路易斯碱。,路易斯碱,Poly(diiododiacetylene) (PIDA) is a,conjugated polymer,containing an all-carbon backbone and,only iodine,atom,substituents.,PIDA,is prepared by topochemical,polymerization of,monomer diiodobutadiyne within hostguest,cocrystals.,stable,at room,temperature,explosive,under external energy,such as,shock or,pressure.,Poly(diiododiacetylene) (PIDA),thermal conditions, carbonization of PIDA fibers starts at 120 C, and complete carbonization can be achieved by pyrolysis at 900 C for 1 h.,irradiated with a 532-nm Raman laser, the PIDA fibers transform irreversibly at room temperature to sp2-hybridized carbon,.,The,generality of this iodine elimination further suggests that reaction of PIDA with Lewis bases dehalogenates the polymer, presenting a new method to prepare carbon nanomaterials at room temperature under very mild,conditions.,pyrrolidine, pyridine, and other amines, can react with PIDA,to release,iodine and thus carbonize the polymer at room,temperature.,Research course,680 nm and a longer-wavelength absorption shoulder that,is associated,with,the ggregation,of the polymer,chains,750 nmdecreases immediately,after the base is added,indicating that,the polymer starts to,deaggregate.,pyrrolidine,causing a faster color transition than pyridine,or triethylamine,at the same concentration.,no,apparent peak above 450 nm,froma metallic luster to dark,gray-black material,maintains,a fibrousmorphology,after reaction with the Lewis,base,mixing bulk PIDA with neat,pyrrolidine results,in a dark, opaque suspension which is difficult to separate,最初实验已证明,:,依赖于离子反应而非极性机制，在甲烷等非极性溶剂中反应很慢或几乎不反应，在四氢呋喃或吡咯烷极性溶剂中,反应，但是从极性溶剂中取出，反应不受到影响。,更详细的机理还有待研究,热重量分析图。降低很平缓。在原始聚合物,150,度开始降低，,550,时还有,18,%,残留。处理过后聚合物,550 C,降低, 44%,残留,.,PIDA,拉曼峰,971, 1407,2074,cm1.,与吡咯烷反应后只有,1360 1580,，与碳纳米纤维 石墨碳类似,表明不定形由于与吡咯烷反应或反应不完全，碳化不充分,碳,13,核磁共振图谱表明这两种物质已有不同的结构和性能,初始的,sp2,和,sp,在反应后都不在存在，被,50150,的宽峰代替处理过后的物质在高强度磁场中不在发生旋转，除非放在没有磁性的盐中。说明能产生涡电流，导电性得到大大增强。,量化分析碳化后产物的导电性，用交变电流进行测试。嘧啶处理过后是原来的,10,多倍，吡咯烷处理过后的是原来,10000,倍,这,与碳,13,MAS,NMR,相符合,.,Lewis,bases can react,with PIDA,to dehalogenate the polymer at room temperature.,at,least60% of the,original iodine,dissociating from the polymer upon,reaction,the,basetreated PIDA,materials exhibit Raman spectra consistent,with graphitic,carbon,a,significantly increased conductivity,.,The reaction,between PIDA and Lewis bases presents a novel,chemical method,to generate one-dimensional carbon nanomaterials,under mild,conditions.,Ongoing,experiments are focused on optimizing,the method,to achieve complete dehalogenation of PIDA and to,form ordered,carbon nanomaterials at room temperature.,summary,Thank you for your attention,
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