Design And Synthesis Of Thieno [3,2-b] Thiophene-based Conjugated Cyclic Macromolecules

The organic conjugated cyclic macromolecules have great potential to be used in organic electronics,such as,organic photovoltaics(OPVs),organic light-emitting diodes(OLEDs)and organic field effect transistor(OFETs).It is mainly due to their following advantages:(1)organic materials are low in cost,light in weight and easy to process;(2)photoelectric properties of such conjugated materials can be easily tuned by introducing vary functional groups;(3)charge carrier transportation is much easier,due to the conjugated planar backbone and intermolecular?-?interactions.Although such conjugated cyclic macromolecules have attracted wide attention and research interest in recent years,the challenge of synthesis restrict their further applications.Thieno[3,2-b]thiophene has a larger?-conjugated plane,thus it is expected that the cycle molecules synthesized with thieno[3,2-b]thiophene units may perform desired properties.For this reason,this thesis aims to build a cyclic functional compound with thieno[3,2-b]thiophene units.Two synthetic routes were designed for the synthesis of the three target compounds TM-1,TM-2 and TM-3.To synthesis these target compounds,17-steps reactions and 10-type reactions were involved.Also,the solubility of the conjugated aromatic skeleton could be improved via introducing long flexible alkyl chains.Then,using stiller coupling,the target compound TM-1 was attempted to be synthesized in dilute solution and the TM-1 was initially confirmed by ~1H-NMR spectrum.Finally,according to the density functional theory(DFT)calculation,it is concluded that all three molecules have good planarity.With increasing the number of cyanide(CN)group,the energy levels of the frontier orbits decrease correspondingly.Compound TM-3 with the quinone structure presents the narrowest band gap of 0.81 eV.This study not only enriches the types of organic conjugated cyclic molecules,but also provides some fundamental synthesis methods for preparing more related species.