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  • 09월 08일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제116회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Efficient Synthesis of Bulky N-Heterocyclic Carbene Ligands for Coinage Metal Complexes

2015년 9월 8일 16시 59분 21초
INOR.P-146 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 15일 (목요일) 11:00~12:30
저자 및
김영석, 김용휘1, 김기문, 이은성*
포항공과대학교(POSTECH) 화학과, Korea
1기초과학연구원 복잡계자기조립연구단, Korea

N-heterocyclic carbenes (NHCs) have been drawing great attention for its excellent roles in catalysis. For past two decades, a variety of NHCs have been developed by not only adjusting electronic and steric properties but also by replacing one nitrogen atom of imidazole ring with carbon atom or sulfur atom. Especially, the steric factor is important because it enhances regio? or stereoselectivity of various reactions and promotes reactivity of certain reactions by stabilizing low-valent intermediates.1 However, synthesis of bulky NHC usually requires some harsh reaction conditions and the multiple reaction steps to afford low chemical yields.2 Therefore, a facile and efficient synthetic route to bulky NHC is highly desired. Here we report the the synthesis of bulky NHC ligands 1a and 1b with imidazo[1,5-a]pyridin-3-ylidene moiety, and their coinage metal complexes. The bulky NHCs were synthesized in four steps with approximately 40% of overall yield depending on the substituents. More interestingly, the method does not require harsh reaction conditions or any chromatographic purification process, which is sustainable for large scale synthesis.3 Copper(I), silver(I), and gold(I) complexes were synthesized and fully characterized by NMR and single crystal X-ray analysis. The percent buried volume4 for copper(I) complex is 55.5%, which indicates the high steric effect (compared to commonly used IPr and IMes with %VBur = 44.5 and 36.5 respectively). Reference [1] Christmann U.; Vilar R. Angew. Chem. Int. Ed. 2005, 44, 366-374. [2] Dierick, S.; Dewez, D. F.; Mark?, I. E. Organometallics 2014, 33, 677?683. [3] Espina, M.; Rivilla, I.; Conde, A.; D?az-Requejo, M. M.; P?rez, P. J.; ?lvarez, E.; Fern?ndez, R.; Lassaletta, J. M. Organometallics 2015, 34, 1328?1338. [4] Calculated via SambVca with following parameters: Radius of sphere = 3.5 ?; Distance from sphere 2.0 ?; Mesh step 0.5 ?; H atoms omitted.