Color tuning of cyclometalated 2-phenylbenzo[d]oxazole-based iridium (III) complexes through modification of different N boolean AND O ancillary ligands

摘要

Four new cyclometalated bo-based iridium(III) complexes with different N boolean AND O ancillary ligands, [Ir(bo)(2)pic] (1), [Ir(bo)(2)prz] (2), [Ir(bo)(2)bop] (3) and [Ir(bo)(2)btp] (4) (bo = 2-phenylbenzo[d]oxazole, pic = picolinate, prz = pyrazinate, bop = 2-benzoxazol-2-yl phenol, btp = 2-benzothiazol-2-yl phenol), have been synthesized and investigated by optical spectroscopy, electrochemistry as well as density functional theory (DFT). The crystal structures of 1, 2 and 4 have been determined, which show that each adopts the distorted octahedral coordination geometry. They exhibit intense green to orange phosphorescence (lambda(max) = 531-598 nm) with quantum yields of 0.19-0.94 and lifetimes of 0.078-0.468 mu s in solution at 298 K. The broad range color tuning of complexes 1-4 is dependent on the ancillary ligand structure. The cyclic voltammetry has been measured, showing a quasireversible, metal-centered oxidation with potentials at 1.00-1.49 V. The frontier molecular orbital diagrams and the lowest-energy electronic transitions of 1-4 have been calculated with density functional theory (DFT) and time-dependent DFT (TD-DFT). (C) 2016 Elsevier B.V. All rights reserved.