Soluble phosphorescent iridium(iii) complexes from cinchonine-derived ligands

Abstract

Cinchonine-derived complexes Ir(L2) 2(acac) (3), Ir(L2) 2(dbm) (4), [Ir-(L1)2(bipy)][PF6] (5), [Ir(L1)2(phen)][PF6] (6), [Ir(L1)2(dppe)][PF6] (7), [Ir-(L2) 2(bipy)][PF6] (8), [Ir(L2) 2(phen)][PF6] (9), and [Ir(L2) 2(dppe)][PF6] (10) (L1 =2-phenyl-9-O-benzyl-10,11-dihydrocinchonine-N,C; L2 = 2-(2,4-difluorophenyl)-9- O-benzyl-10,11-dihydrocinchonine-N,C; acac = acetylacetonate; dbm = dibenzoylmethane; bipy =2,2-bipyridine; phen = 1,10-phenanthroline; dppe = (Z)-1,2-bis(diphenylphosphino)ethene) are highly soluble in common organic solvents and phosphoresce with emission wavelengths from orange to green (583529 nm) and internal quantum efficiencies from 4 to 24%. The emission is blue-shifted for the neutral auxiliary ligands and/or by incorporation of fluorine into the alkaloid-based chromophore. An unprecedented regiospecific monohydrodefluorination of L2, giving 2-(4-fluorophenyl)-9-O-benzyl-10,11- dihydrocinchonine (L2), occurred during the synthesis of 3 and 4. © 2012 American Chemical Society.