The Preparation Of Diseleno[2,3-b:3',2'-d] Selenophene(Thiophene) And Hetero[7] Helicene Based On DSS (DST)

Recently, conjugated polymers, oligomers or organic small molecules employed as active layers in organic field effect transistors(OFETs) are of great current interest because such OFETs can potentially be fabricated at low cost, over large areas, and on flexible substrates. In this thesis, 2,5-di(trimethylsilanyl)-diseleno[2,3-b:3',2'-d]selenophene(DSS) and 2,5-di(trimethylsilanyl)-diseleno[2,3-b:3',2'-d]thiophene(DST) were synthesized starting from selenophene. In addition, hetero[7]helicene and functionalized derivatives based on DSS and DST were prepared. My research work is separated into three parts as following:1. Study on synthesis 2,5-di(trimethylsilanyl)-diseleno[2,3-b:3',2'-d]selenophene(thiophene)Starting from selenophene, through bromination, TMS protection, bromine dance reaction, oxidized with Cu Cl2, intramolecular cyclization with selenium, copper powder reduction to afford 2,5-di(trimethylsilanyl)-diseleno[2,3-b:3',2'-d]selenophene((TMS)2-DSS, 5). Compound 5 was obtained with total yield of 39%. With selenophene as the starting material, according to the above steps, the product of oxidized with Cu Cl2 via intramolecular cyclization with(Ph SO2)2S to prepare 2,5-di(trimethylsilanyl)-diseleno[2,3-b:3',2'-d]thiophene((TMS)2-DST, 7), Compound 7 was obtained with total yield of 44%. All intermediates, 5 and 7 were confirmed by NMR, MS, HRMS and IR spectrum.2. Study on synthesis of hetero[7]helicene based on DSS and DSTWith compounds(TMS)2-DSS and(TMS)2-DST as starting materials, respectively, by bromination, Li/Br exchange and quenching with DMF, Mc Murry reaction,1,2-bis(5-(trimethylsilyl)diseleno[2,3-b:3',2'-d]selenophene-2-yl)ethane(16) and 1,2-bis(5-(trimethylsilyl)diseleno[2,3-b:3',2'-d]thiophene-2-yl)ethane(17) were obtained. 16 and 17 through oxidative photocyclization reaction hetero[7]helicene 18 and 19 were synthesized, with total yield of 6.2% and 5.3%, respectively. All the intermediates and hetero[7]helicene were characteriazed by NMR, MS, HRMS spectrum.3. Study on synthesis of 2,5-bis(4-octylstyryl)-diseleno[2,3-b:3',2'-d]selenophene(thiophene)Starting from(TMS)2-DSS and(TMS)2-DST, through bromination, Br/Li exchange and, quenching with DMF diseleno[2,3-b:3',2'-d]selenophene-2,5-dialdehyde(14) and diseleno[2,3-b:3',2'-d]thiophene-2,5-dialdehyde(15) were obtained in total yield of 55% and 50%, respectively. 14 and 15 via Wittig reaction 2,5-bis(4-octylstyryl)-diseleno[2,3-b:3',2'-d] selenophene(20) and 2,5-bis(4-octylstyryl)-diseleno[2,3-b:3',2'-d]thiophene(21) were prepared in yield of 82%, 76%, respectively. All the intermediates and 2,5-bis(4-octylstyryl)-diseleno[2,3-b:3',2'-d]selenophene(thiophene) were characteriazed by NMR, MS, HRMS spectrum.