基于杂原子三角烯和咔唑有机功能材料的合成与性质研究

【作者】 张华强；

【导师】 陈永胜；

【作者基本信息】 南开大学 ， 有机化学， 2009， 博士

【摘要】 本论文以杂原子三角烯为受体核,咔唑为给体枝通过铜催化的Ullmann反应合成了具有给受体结构的两代星形树枝状化合物（G1和G2）。吸收光谱和电化学结果表明,G1和G2在基态时均发生由给体树枝向受体核的分子内电子转移。溶液中G1和G2的荧光在短波处产生浓度淬灭效应,在长波处随着浓度的增加,荧光强度增加。它们的固体荧光表现出很强的宽峰,并且不产生浓度淬灭效应。因此,我们以G1和G2为主体发光材料制得的有机发光二极管,电致荧光发射峰在600和630 nm,和其它类似树枝状化合物相比,具有较好的性能:对于G1,电流效率在5.3 cd A^-1时达到最大发光亮度1586 cd m^-2;对于G2,电流效率在6.9 cd A^-1时达到最大发光亮度827 cd m^-2。杂原子三角烯的大π共轭体系,使它在盘状液晶及柱状超分子自组装材料领域具有潜在的应用价值。我们以杂原子三角烯为刚性核,对烷氧基苯乙炔为柔性链,合成了5种化合物。其中6到12个碳链长度的化合物具有很好的自组装性质,而10和12个碳链长度的化合物同时具有柱状液晶性质。我们以咔唑为电子给体,蒽和苯并噻二唑为电子受体合成了6个具有给体-受体-给体结构的线性有机小分子。通过改变受体分子电负性以及桥的有效共轭长度来实现对分子能级及能隙宽度的调控,以期适合不同有机材料的选择。基本的紫外,荧光和电化学结果表明这些小分子能隙调控的目的已经达到。理论计算和实验结果能很好地符合。我们成功合成了1,9-二氮phenalenyl自由基,并测定了其ESR信号。结果表明,该自由基非常稳定。于是我们进一步合成六氮杂结构的phenalenyl自由基,计算表明,该自由基前体N-H键的均裂能接近100 kcal mol^-1,常用的氧化剂如氧化银,活性二氧化铅,二氯二硫等都很难将其氧化。将并四苯进行适当的修饰会改变它固体的堆积方式,提高它的稳定性及迁移率。考虑到氯原子具有稳定电子云的作用,我们合成了5,6,11,12-四氯并四苯,并以它作为活性层制备场效应晶体管（FET）器件,迁移率测试结果表明,此化合物为p-型半导体。更多还原

【Abstract】 In this dissertation, two star shaped donor-acceptor dendrimers based on heterotriangulene and carbazole were synthesized through Ullmann reactions. The dendrimers show distinct ground state intramolecular charge transfer （ICT） transitions as confirmed by UV-vis along with cyclic voltammetric studies. The dendrimers show efficient aggregation-induced emissions originated from the carbazole dendrons, heterotriangulene core, intramolecular charge transfer （ICT） and intermolecular aggregation absorptions. The OLEDs fabricated with G1 and G2 as non-doping emitters exhibit exclusive aggregation-induced luminescence peaking at 600 and 630 nm, respectively, and demonstrate a good performance with maximum luminance of 1586 cd m^-2 at current efficiency of 5.3 cd A^-1 for G1 and 827 cd m^-2 at current efficiency of 6.9 cd A^-1 for G2.The largeπ-conjugation disc-like structure of heterotriangulene makes itself a good electron-attractive building block for star shaped electronic networks with potential applications for discotic liquid crystals and supramolecular assembly based electronic devices. Herein, we synthesized a series of disc like molecules incorporating heterotriangulene as rigid core, p-alkoxy phenylacetylene as side chains. The compounds with six to twelve side chains have good self-assembly properties, and the compounds with ten and twelve carbon side chains have column liquid crystal properties as well.A series of linear molecules with donor-acceptor-donor type, incorparating carbazole as donor, anthracene or benzothiadiazole as acceptor, have been synthesized. Different energy levels and band gaps of these molecules were tuned by adjusting the affinity of acceptors and effect conjugation length of theπbridges. The results of absorption, emission spectra and electrochemical studies indicate that the band gaps of these molecules are effectively controlled. Theoretical calculations were also conducted to gain further insight into the mechanisms, and gave good agreement with experiment. A new two nitrogen containing hetero-phenalenyl radical has been synthesized. The ESR spectra indicate that the radical is very stable. So, we are likely to synthesize six nitrogen containing hetero-phenalenyl radical, which is expected to show more stability. But to our surprise, the calculation results indicate that the homolytic bond dissociation enthalpy （BDE） of N-H bond for the precursor of six nitrogen containing hetero-phenalenyl radical is as high as 100 kcal mol^-1, which overhead the ability of the oxidants such as silver oxide, active lead dioxide and S₂Cl₂ to abstract the hydrogen from the N-H bond.It is reported before that tetracene is good FET materials with high charge mobilites. But it has less stability. A proper modification to the tetracene is helpful to enhance the stability. Considering the stabilization of chlorine atom to electrons, we syntheszied 5,6,11,12-tetrachlorotetracene. Single crystal field-effect transistors based on tetrachlorotetracene were fabricated and showed p-type behaviors with the highest field-effect mobility of 1.7 cm²/V s.更多还原