Fan Jun, Chia Pei-Ting, Zhang Zheng-Feng, Yang Ming-Chung, Su Ming-Der, So Cheuk-Wai
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore.
Department of Applied Chemistry, National Chiayi University, Chiayi, 60004, Taiwan.
Angew Chem Int Ed Engl. 2022 Nov 14;61(46):e202212842. doi: 10.1002/anie.202212842. Epub 2022 Oct 17.
A boron analogue of vinyl cation, pyridine-stabilized N-phosphinoamidinato N-heterocyclic carbene (NHC)-diboravinyl cation 2 , was synthesized by displacement of bromide in diborene 1 with excess pyridine. Experimental and computational studies showed that the positive charge is mainly at the B-B skeleton with delocalization to the pyridine ligand. One of the main modes of reactivity is through the B=B double bond alongside activation of the pyridine substituent, where the B center is the predominant nucleophilic center and the predominant electrophilic center is either the activated pyridine para position or the B center, illustrating the presence of diborene cation A, borylene-borenium cation B and diborene-pyridinium cation C resonance structures in cation 2 .
通过用过量吡啶取代双硼烯1中的溴化物，合成了乙烯基阳离子的硼类似物，吡啶稳定的N-膦基脒基N-杂环卡宾（NHC）-二硼乙烯基阳离子2。实验和计算研究表明，正电荷主要位于B-B骨架上，并离域到吡啶配体上。主要反应模式之一是通过B=B双键以及吡啶取代基的活化，其中B中心是主要的亲核中心，主要的亲电中心是活化的吡啶对位或B中心，这说明了阳离子2中存在双硼烯阳离子A、硼烯-硼鎓阳离子B和双硼烯-吡啶鎓阳离子C的共振结构。
