The photodecomposition product μ-oxalato-lκ 2O,O′:2κ 2O′,O‴-bis{bis[2-(2-pyridyl)phenyl-κ 2C,N]iridium(III)}-acetone (1/1.974)

An attempt to grow crystals of [Ir(ppy)2(vacac)], (I), from an acetone-d6 solution formed instead crystals of [(Ir(ppy) 2)2(μ-oxalato)] acetone solvate, (II), [Ir 2C11H8N)4(C2O 4)]·-1.974C3H6O, where ppy is the phenylpyridine anion and vacac is vinylacetylacetonate. Each IrIII ion in (II) is in a pseudooctahedral coordination environment, where the pyridine N atoms are trans to each other and the phenyl C atoms are trans to the O atoms of the oxalate bridging ligand. There are two crystallographically independent dimer molecules, each lying on an inversion centre. It is suggested that the oxalate ligand is formed in a series of steps initiated by the aldol condensation of acetone with vacac

Iridium luminophore complexes for unimolecular oxygen sensors

In this study, a series of novel luminescent cyclometalated Ir(III) complexes has been synthesized and evaluated for use in unimolecular oxygen-sensing materials. The complexes Ir(C6)2(vacac), 1, Ir(ppy)2-(vacac), 2, fac-Ir(ppy)2(vppy), 3, and mer-Ir(ppy)2(vppy), 4, where C6 = Coumarin 6, vacac = allylaceto-acetate, ppy = 2-phenylpyridine, and vppy = 2-(4-vinylphenyl) pyridine, all have pendent vinyl or allyl groups for polymer attachment via the hydrosilation reaction. These luminophore complexes were characterized by NMR, absorption, and emission spectroscopy, luminescence lifetime and quantum yield measurements, elemental analysis, and cyclic voltammetry. Complex 1 was structurally characterized using X-ray crystallography, and a series of 1-D (1H, 13C) and 2-D (1H-1H, 1H-13C) NMR experiments were used to resolve the solution structure of 4. Complexes 1 and 3 displayed the longest luminescence lifetimes and largest quantum efficiencies in solution (τ = 6.0 μs, φ = 0.22 for 1; τ = 0.4 μs, φ = 0.2 for 3) and, as result, are the most promising candidates for future luminescence-quenching-based oxygen-sensing studies