Iodine(I) and Silver(I) Complexes Incorporating 3‑Substituted Pyridines

Building upon the
first report of a 3-acetaminopyridine-based iodine(I)
complex (1b) and its unexpected reactivity toward tBuOMe, several new 3-substituted iodine(I) complexes (2b–5b) have been synthesized. The iodine(I) complexes
were synthesized from their analogous silver(I) complexes (2a–5a) via a silver(I) to iodine(I) cation exchange reaction, incorporating
functionally related substituents as 3-acetaminopyridine in 1b; 3-acetylpyridine (3-Acpy; 2), 3-aminopyridine
(3-NH2py; 3), and 3-dimethylaminopyridine
(3-NMe2py; 4), as well as the strongly electron-withdrawing
3-cyanopyridine (3-CNpy; 5), to probe the possible limitations
of iodine(I) complex formation. The individual properties of these
rare examples of iodine(I) complexes incorporating 3-substituted pyridines
are also compared to each other and contrasted to their 4-substituted
counterparts which are more prevalent in the literature. While the
reactivity of 1b toward etheric solvents could not be
reproduced in any of the functionally related analogues synthesized
herein, the reactivity of 1b was further expanded to
a second etheric solvent. Reaction of bis(3-acetaminopyridine)iodine(I)
(1b) and iPr2O gave [3-acetamido-1-(3-iodo-2-methylpentan-2-yl)pyridin-1-ium]PF6 (1d), which demonstrated potentially useful
C–C and C–I bond formation under ambient conditions.