Bis(pyridine)-based bromonium ions. Molecular structures of bis(2,4,6-collidine)bromonium perchlorate and bis(pyridine)bromonium triflate and the mechanism of the reactions of 1,2-bis(2'-pyridylethynyl)benzenebrominum triflate and bis(pyridine)bromonium triflate with acceptor olefins.
