Electronic Nature of New Ir(III) Complexes: Linear Spectroscopic and Nonlinear Optical Properties

Abstract

Comprehensive investigations of the linear and nonlinear optical properties of new Ir(III)-complexes [Ir(pbt)2(dbm)] (1), [Ir(pbt)2(dmac)] (2), and [Ir(pbt)2(minc)] (3) (pbt=2-phenylbenzothiazole; dbm=dibenzoyl methane; dmac=(1E,4Z,6E)-1,7-bis(4-(dimethylamino)phenyl)-5-hydroxyhepta-1,4,6-trien-3-one; minc=(1E,4Z,6E)-5-hydroxy-1,7-bis(1-methyl-1H-indol-3-yl)hepta-1,4,6-trien-3-one) are reported, including, photostability, two-photon absorption, and femtosecond transient absorption spectroscopy. The steady-state and time-resolved spectral properties of 1-3 revealed the electronic nature of the absorption bands, and photoluminescence emission of 2 and 3 shows both fluorescence and phosphorescence processes occurring simultaneously in liquid solution at room temperature. This unusual behavior of 2 and 3 can be explained by a dual-minimum potential surface of the excited electronic state resulting in two independent fluorescence and phosphorescence emission channels. The degenerate 2PA spectra of 1-3 were obt...