Gram Scale Synthesis of Benzophenanthroline and Its Blue Phosphorescent Platinum Complex

The design, synthesis, and characterization of 12-phenylbenzo[f][1,7]phenanthroline, Bzp, is reported. Its use as a fluorine-free ligand for sky blue phosphorescence is demonstrated in a cyclometalated platinum complex, BzpPtDpm. BzpPtDpm phosphoresces at the same wavelength as its analogous 4,6-difluorophenylpyridine complex at both room temperature (466 nm) and 77 K (458 nm). Finally, production of a conformationally restricted derivative of BzpPtDpm with greatly increased quantum yield (46%) validates the versatility of the synthetic route.