| 摘要: | 近年來，人們越來越注重環保議題，研究發展對現今社會固然重要，但發展過程中如何降低對環境的危害也同樣備受重視，一般在製備多功能π-共軛材料時，大部分是以傳統多步驟的人名反應為主，然而，此方法合成步驟繁雜、會使用到危害環境的有機金屬試劑且成本高，因此，本研究團隊引入綠色化學的理念，嘗試使用新型的省步驟合成途徑，製備出一系列π-共軛有機光電材料之前驅物分子。
在多篇參考文獻中，大多數團隊在噻吩(thiophene)3號位上引入像是甲氧基、酯基、醛基等作為引導基，卻鮮少有人使用鹵素作為引導基，因此本團隊認為，若能使用鹵素當作引導基製備π-共軛有機光電材料之前驅物分子，其後續應用可延伸進行不同的官能化反應，故本篇研究選用3-溴噻吩及芳基碘化物作為原料，以鈀催化直接碳氫鍵芳香環化合成有機光電材料中常見的π-共軛單元。
在本篇工作中我們發現，利用3-溴噻吩(3-bromothiophene)作為反應物並在溫和的反應條件下，以高度選擇性獲得噻吩2號位芳基化產物並有最高達90 %的分離產率，其中部分研究結果顯示即便在不含任何有機溶劑的純水條件下亦能反應，產率也有中等的表現，且反應結果具有高度位向選擇性及化學選擇性。
此外，我們將上述方法學應用於合成新型有機π-共軛小分子:MLC01及MLC02，並製備成鈣鈦礦太陽能電池(Perovskite Solar Cells, PSCs)中的電洞傳輸層(Hole-Transporting Layer, HTM)，其光電轉換效率(Power Conversion Efficiency, PCE)分別為17.0 %及11.8 %。;Generally, when preparing multifunctional π-conjugated materials, most of them are usually prepared using the traditional multi-step name reaction, which is the main method. However, this method has complicated synthesis steps, uses organometallic reagents that are harmful to the environment, and is expensive. Therefore, our research team introduced the concept of green chemistry and tried to use a new type of step-saving synthesis approach to prepare a series of building blocks for π-conjugated organic optoelectronic materials.
In many references, most teams have introduced methoxy, ester, aldehyde, etc. as directing groups at the C3 position of thiophene, but only a few have used halogens as directing groups. Therefore, our team believes that if halogen can be used as a directing group to prepare building blocks for π-conjugated organic optoelectronic materials, its subsequent application can be extended to carry out different functionalization reactions. In this study, 3-bromothiophene and aryl iodide were used as raw materials to synthesize π-conjugated units common in organic optoelectronic materials by palladium-catalyzed direct C-H arylations.
In this study, we discovered that by using 3-bromothiophene as a reactant and under mild reaction conditions, we were able to obtain the arylation product at the C2 position of the thiophene with high selectivity and isolated yields of up to 90 %. Some of the research results also showed that the reaction could occur even under the conditions of pure water without any organic solvent, and the yield was moderate. Furthermore, the reaction exhibited highly regioselective and chemoselective properties.
In addition, we applied the above methodology to the synthesis of novel organic π-conjugated small molecules: MLC01 and MLC02, which were fabricated into hole-transporting layer in perovskite solar cells, with power conversion efficiency of 17.0 % and 11.8 %, respectively. |
