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Updated: Jun 4, 2025

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
Salts of 2-amino-5-iodo-pyridinium
Benjamin A Mukda1, Diane A Dickie2, Mark M Turnbull1
1Carlson School of Chemistry and Biochemistry, Clark University, 950 Main St., Worcester, MA 01610, USA.
Abstract:
Reaction of 2-amino-5-iodo-pyridine (5IAP) with concentrated HBr at room temperature yielded 2-amino-5-iodo-pyridinium bromide, C5H6IN2 +·Br- or (5IAPH)Br. The complex formed pale-yellow crystals, which exhibit significant hydrogen bonding between the amino and pyridinium N-H donors and bromide ion acceptors. Halogen bonding is also observed. Similarly, reaction of 5IAP with cobalt(II) chloride in mixed HCl/HBr in 1-propanol yielded 2-amino-5-iodo-pyridinium (2-amino-5-iodo-pyridine-κN 1)bromido/chlorido-(0.51/2.48)cobalt(II), (C5H6IN2)[CoBr0.51Cl2.48(C5H5IN2)] or (5-IAPH)[(5IAP)CoCl2.48Br0.51], as blue block-shaped crystals. Two of the three halide positions exhibit mixed occupancy [Cl/Br = 0.797 (5):0.203 (5) and 0.689 (6):0.311 (6)], while the third position is occupied solely by a chloride ion. Extensive hydrogen and halogen bonding is observed.
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