Design And Synthesis Of Ladder-type Conjugated Oligomers Containing Pyrene Units And Novel Acceptor Ladder-Type Conjugated Polymers

Ladder-type conjugated polymers have indicated the extensive potentials in optoelectronic materials.So design and synthesis of ladder-type conjugated polymers has been a hotspot in the research of the field of materials chemistry.The work in this dissertation is mainly to design and synthesis a series of ladder-type oligomers and ladder-type polymers with fully conjugated structure and large?conjugated planes.The structures and properties of the ladder-type oligomers and polymers are studied in detail.This work provides a route for synthesis of ladder-type oligomers and polymers with fully conjugated structure,and also provides a scientific basis for its application in field of optoelectronic materials.First,ladder or ribbon-type polymers and oligomers possessing two dimensionally planar conformation,high electron delocalization,and functional opticelectronic properties attract great scientific interest.Pyrene,which has been widely investigated for its unique properties,is a promising building block to develop new extended?-systems for organic optoelectronics.In this paper,2,7-di-tert-butylhydrazine was used as the starting material.Three ribbon-type oligomers 1,2and 3 were synthesized by Suzuki coupling reaction and typical strategy of polycyclic aromatic hydrocarbon(PAH)production.Ribbon-type oligomers with larger graphene are designed,but only obtained the corresponding chlorination by-product,compound14.The spectroscopic and thermal properties of four oligomers were characterized by UV-vis spectroscopy,fluorescence spectroscopy,cyclic voltammetry and thermal analysis.The oligomers have absorption peaks in the ultraviolet region and present a bright blue light emission both in solution and in a thin film environment.Oligomers exhibited good thermal stability and good solubility.Second,it is well known that the incorporation of other heteroatoms,such as N,O,S,Si and P,can effectively fine-tune the valence electron structures and thus afford?-conjugated organoboron materials with desirable properties.A ladder-type BN-heteroacene and its polymer derivative were obtained in high yields by using a Pd~0-catalyzed Suzuki reaction followed by ring closure with phenylboron dichloride.The BN-heteroacene and polyheteroacene show good solubility in commonly used solvents,high thermal stability and strong blue and green light emission.The Mn of polymer is 8.3×10~3 g/mol.The maximum absorption peaks of the compound 4 and polymer P2 were 306 nm and 453 nm,and the emission peaks were 418 nm and 482 nm,respectively.The HOMO values of polymer P2 and compound 4 were-5.01 eV and-5.51 eV,respectively.These properties indicate that the BN-heteroacene and polyheteroacene have a great potential for application in organic electronics.Third,D-A conjugated polymer with NDI as electron-acceptor unit and carbazoles as the electron donor were designed and synthesized.Then,use acid-catalyzed intramolecular ring closing reaction to prepare the n-type fully conjugated polymer material.The structures and properties of ladder-type fully conjugated polymer materials were characterized by NMR,FTIR,TGA,UV spectroscopy and cyclic voltammetry.Polymer P(NDI-CZL)has good solubility and thermal stability.The number average molecular weight of polymer P(NDI-CZL)is 18.9×10~3g/mol.The maximum absorption peak of polymer P(NDI-CZL)was 525 nm.The HOMO of polymer P(NDI-CZL)was-5.51 eV.Fourth,D-A conjugated polymer with NDI as electron-acceptor unit and 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene as the electron donor were designed and synthesized.Then,use acid-catalyzed intramolecular ring closing reaction to prepare the ladder-type fully conjugated polymer material.The structures and properties of ladder-type fully conjugated polymer materials were characterized by NMR,FTIR,TGA,UV spectroscopy and cyclic voltammetry.Polymer P(NDI-TTL)has good solubility and thermal stability.The number average molecular weight of polymer P(NDI-TTL)is 26.0×10~3 g/mol.The maximum absorption peak of polymer P(NDI-TTL)was 545 nm.The HOMO of polymer P(NDI-TTL)was-5.75 eV.