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烷基芴类化合物的合成及性能研究

Synthesis and Property of Alkyl Fuluorene

【作者】 栗婷婷

【导师】 万有志;

【作者基本信息】 北京化工大学 , 化学工程与技术, 2010, 硕士

【摘要】 芴的聚合物是一类重要的蓝色高分子发光材料,广泛应用于高分子平板显示(PLEDs),太阳能电池,生物和化学传感器等领域。由于聚芴分子间的聚集效应或链间低聚物的形成,它的发光光谱有很大的拖尾现象,即色纯度和发光颜色稳定性差。因而,围绕聚芴分子的修饰和改性,人们做了大量的工作,合成了一些聚芴衍生物的高分子发光材料。由于在芴的9位上引入烷基侧链,可使这类高分子材料具有较好的溶解性和可加工性,被认为是很有发展前景的一类高分子。本文以芴为主要原料,分别采用两种不同的合成路线,合成了一系列含有不同烷基链(-C4H9,-C8H17,-C14H29)的烷基芴类小分子单体溴代烷基芴(A)和羧基烷基芴(B):R=-C4H9,-C8H17,-C14H29A的合成路线一:先将芴的2位和7位进行溴代反应,然后再将9位进行烷基化反应。合成溴代烷基芴时,在不同的反应条件下,分别采用TEBA、四丁基溴化铵作为相转移催化剂,甲苯、DMSO和THF做溶剂,50%NaOH和叔丁醇钾做活化剂。A的合成路线二:先将芴的9位进行烷基化反应,再将2位和7位进行溴代反应。9位进行烷基化反应时,在不同反应条件下,分别采用正丁基锂和叔丁醇钠作为活化剂。分别采用格氏反应和正丁基锂活化反应的方法合成目标产物B。通过1HNMR,IR对其结构进行了表征,紫外,荧光等检测方法探讨了其发光性能,得到结论如下:1.芴的9位上所连的烷基链越短,紫外最大吸收波长越大。由于所连的烷基链减弱了芴的共轭性,从而导致了紫外最大吸收波长的蓝移,链越长,相对蓝移程度越大。2.芴的9位上所接烷基链长度的增加对荧光最大吸收波长影响不大,且都在310nm左右,但是随着链长度的增加,荧光强度逐渐增加;可能是由于链长度的增加阻碍了荧光自淬灭。3.9,9-二烷基-2,7-二溴芴的合成路线的选择对反应条件和产率的影响表明,先将芴溴代,然后再烷基化,这样得到的产物产率高,且反应条件简单。且常温下,用THF做溶剂,叔丁醇钾做活化剂的条件下得到的产品产率最高。4.采用格氏试剂法合成羧基烷基芴的方法简单、不需要高温条件且产率较高。

【Abstract】 Polyfluorene is an important class of blue light-emitting polymer material, which is widely used in flat panel displays(PLEDs), solar cells, biological and chemical sensors. As mass effect or formation of chains oligomer among the polyfluorene molecules, there is a tailing phenomena in light spectrum, meaning poor color purity and poor stability. Thus, people had done a lot of work to focus on the modification of polyfluorene, and synthesized a number of light-emitting polyfluorene derivative. Polyalkylfluorine is considered as a promising polymer due to its better solubility and processability with alkyl side chain connected to the bridge carbon.A series of poly alkyl fluorene monomers with different alkyl chain(-C4H9,-C8H17,-C14H29) are synthesized by using of fluorene as raw material, according to different synthetic routes, choosing different solvents and catalysts in this paper. R=-C4H9,-C8H17,-C14H29 Synthetic route 1 of A:First 2,7-dibromo fluorine is synthesized, and second it is alkylated. Alkyl bromide fluorene is prepared under different reaction conditions by using TEBA, tetrabutylammonium bromide as phase transfer catalyst, toluene, DMSO and THF as solvent, 50% NaOH and potassium tert-butoxide as activator respectively.Synthetic route 2 of A:First fluorene is alkylated, and second it is bromide by number 2 and 7. Alkyl fluorene is prepared under different reaction conditions by using butyl lithium and sodium tert-butoxide as activator respectively.Desired product B is prepared with the methods of Grignard reaction and butyl lithium as activator respectively.The structure was characterized by 1HNR and IR. The luminescence was detected by UV and fluorescence. Conclusions were as follows:1. The shorter the alkyl chain connected to fluorine is, the UV maximum absorption wavelength is greater. As the alkyl chain weaken fluorene conjugation, leading to a blue shift of maximum absorption. The longer the chain is, the greater the degree of blue shift is.2. The length of alkyl chain connected to fluorene had little effect on increasing the maximum absorption wavelength. Absorption wavelength was all around 310nm. However, with the chain length increaseing, the fluorescence intensity gradually increased. May be the increasing chain length hindered fluorescence quenching.3. The effect of choice of synthetic route on the reaction conditions and yield showed that, good yield could be got by bromide first and alkylation second, at the same time, the reaction conditions were simple. The highest yield of the product was got by using THF as solvent, potassium tert-butoxide as activator at room temperature.4. Synthetic steps of carboxylic-alkyl-fluorene with Grignard reagent were trouble, but conditions were simple with high yield.

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