Blue luminescent three-coordinate organoboron compounds with a 2,2′-dipyridylamino functional group

Two new three-coordinate organoboron compounds tris[p-(2,2'dipyridylamino) phenylduryl]borane (1) and tris[p-(2,2'dipyridylamino)biphenylduryl]borane (2) have been synthesized in good yields by using Pd-catalyzed Suzuki-Miyauya coupling reactions between tri(p-iododuryl)borane and the corresponding boronic acid. Both compounds display bright blue luminescence when irradiated by UV light. The emission band of both compounds is highly solvent-dependent, indicating the presence of a highly polarized excited state. These new boron compounds are stable under air in solution and the solid state, and are capable of binding to metal ions such as Zn(II) via the 2,2'-dipyridylamino chelating sites. The crystal structures of 1 and 2 have been determined.