A pyridine-stabilized N-phosphinoamidinato N-heterocyclic carbene-diboravinyl cation: boron analogue of vinyl cation

• Main Authors: Fan, Jun, Chia, Pei-Ting, Zhang, Zheng-Feng, Yang, Ming-Chung, Su, Ming-Der, So, Cheuk-Wai
• Other Authors: School of Chemistry, Chemical Engineering and Biotechnology
• Format: Article
• Language: English
• Published: 2023
• Subjects: Science::Chemistry; Boron; Diborene
• Online Access: https://hdl.handle.net/10356/164639
• Institution: Nanyang Technological University

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 Bpyridine center is the predominant nucleophilic center and the predominant electrophilic center is either the activated pyridine para position or the BNHC center, illustrating the presence of diborene cation A, borylene-borenium cation B and diborene-pyridinium cation C resonance structures in cation 2+ .