We report a new family of homoleptic iridium(III) complexes that emit blue phosphorescence at room
temperature. The iridium(III) complexes are comprised of phenyltriazole ligands and were easily prepared
via short synthetic routes. The parent fac-tris(1-methyl-5-phenyl-3-propyl-[1,2,4]triazolyl)iridium(III)
complex exhibits blue photoluminescence (PL) with emission peaks at 449 and 479 nm and has a solution
PL quantum yield of 66%. The emission was sequentially blue-shifted by the attachment of one and two
fluorine atoms to the ligand phenyl ring with the fac-tris{1-methyl-5-(4,6-difluorophenyl)-3-propyl-[1,2,4]triazolyl}iridium(III) complex having the 1931 Commission Internationale de l'Eclairage coordinates of
(0.16, 0.12) at room temperature. In contrast, when the phenyl ring of the ligands was substituted by
trifluoromethyl, the PL spectrum was red-shifted when compared to the parent compound whereas if the
trifluoromethyl group was attached to the triazole ring, the emission was blue-shifted. The radiative rates
of these new blue iridium(III) complexes were found to be in the range of 2−6 × 105 s-1, indicating that
the emission had varying amounts of metal-to-ligand charge-transfer character. Molecular orbital calculations showed that for the fluorinated complexes the contribution of the ligand triplet character to the
emissive energy state increased with the hypsochromic shift in emission. This was confirmed by time-resolved PL measurements, which showed that the complex with the deepest blue emission had the slowest
radiative decay rate.
The imidazo[1,5-a]pyridine skeleton provides a versatile platform for the generation of new types of stable N-heterocyclic carbenes. Rh(I) mono- (6) and biscarbenes (7) from imidazo[1,5-a]pyridin-3-ylidenes (ImPy) and derivatives such as 13 from a mesoionic carbene were synthesized and characterized.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.