Exploring the Chemistry and Photophysics of Substituted Picolinates Positional Isomers in Iridium(III) Bisphenylpyridine Complexes

A simple and versatile route for modifying picolinate ligands coordinated to iridium is described. Reacting a μ-chloro iridium­(C∧N) dimer (where C∧N is a phenylpyridine-based ligand) with bromopicolinic acid (HpicBr) yields the corresponding iridium­(C∧N)2(picBr) complexes (1–4 and 11), which were readily modified by a Sonogashira reaction to give eight alkyne-substituted picolinate complexes (5–10, 12, and 13). The luminescent behavior of these complexes shows that the position of substitution about the picolinate ring has an effect on both photophysical behavior as well as the reactivity.