维蒂希烃的N-杂环卡宾类似物
N-Heterocyclic Carbene Analogues of Wittig Hydrocarbon.
作者信息
Steffenfauseweh Henric, Vishnevskiy Yury V, Neumann Beate, Stammler Hans-Georg, de Bruin Bas, Ghadwal Rajendra S
机构信息
Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615, Bielefeld, Germany.
University of Amsterdam (UvA), Faculty of Science, Van 't Hoff Institute for Molecular Sciences (HIMS), Homogeneous and Supramolecular Catalysis Group, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
出版信息
Chemistry. 2024 May 8;30(26):e202400879. doi: 10.1002/chem.202400879. Epub 2024 Apr 16.
N-Heterocyclic carbene (NHC) analogues of Wittig hydrocarbon, [(NHC)(Stil)(NHC)] (3a-c) (NHC = SIPr (1a) = C[N(Dipp)CH], Dipp = 2,6-iPrCH; IPr (1b) = C[N(Dipp)CH]; Me-IPr (1c) = C[N(Dipp)CMe] and Stil = CHCHCHCH) have been reported as crystalline solids. 3a-c are prepared by two-electron reductions of the corresponding bis-1,3-imidazoli(ni)um bromides (NHC)(Stil)NHC) (2a-c) with KC in >94 % yields. 2a-c are accessible by the nickel catalyzed direct C-C coupling of NHCs (1a-c) with (E)-4,4'-dibromostilbene. One-electron oxidation of 3a,b yields the corresponding radical cations [(NHC)(Stil)NHC)]B(CF) 4a,b. All compounds have been characterized by UV-Vis/NMR/EPR spectroscopy as well as 2a, 3a, and 3b by single crystal X-ray diffraction. The electronic structures of representative systems have been analyzed by quantum chemical calculations.
维蒂希烃的N-杂环卡宾（NHC）类似物[(NHC)(Stil)(NHC)] (3a - c)（NHC = SIPr (1a) = C[N(Dipp)CH]，Dipp = 2,6 - iPr₂CH；IPr (1b) = C[N(Dipp)CH]；Me - IPr (1c) = C[N(Dipp)CMe]且Stil = CH₂CH₂CH₂CH₂）已被报道为晶体固体。3a - c是通过用KC对相应的双-1,3 - 咪唑鎓溴化物(NHC)(Stil)NHC) (2a - c)进行双电子还原制备的，产率>94%。2a - c可通过镍催化的NHCs（1a - c）与(E)-4,4'-二溴芪的直接C - C偶联合成。3a、b的单电子氧化产生相应的自由基阳离子[(NHC)(Stil)NHC)]⁺B(C₆F₅)₄⁻ 4a、b。所有化合物均通过紫外-可见/核磁共振/电子顺磁共振光谱进行了表征，2a、3a和3b还通过单晶X射线衍射进行了表征。代表性体系的电子结构已通过量子化学计算进行了分析。
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