A series of tris-heteroleptic iridium complexes of the form [Ir(C^N1)(C^N2)(acac)] combining 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)pyridine (dFppy), 1-phenylpyrazole (ppz), and 1-(2,4-difluorophenyl)pyrazole (dFppz) as the C^N ligands have been synthesized and fully characterized by NMR, X-ray crystallography, UV-vis absorption and emission spectroscopy, and electrochemical methods. It is shown that "static properties" (e.g., absorption and emission spectra and redox potentials) are primarily dictated by the overall architecture of the complex, while "dynamic properties" (e.g., excited-state lifetime and radiative and nonradiative rate constants) are, in addition, sensitive to the specific positioning of the substituents. As a result, the two complexes [Ir(dFppy)(ppz)(acac)] and [Ir(ppy)(dFppz)(acac)] have the same emission maxima and redox potentials, but their radiative and nonradiative rate constants differ significantly by a factor ∼2. Then acetylacetonate (acac) was replaced by picolinate (pic), and two pairs of diastereoisomers were obtained. As expected, the use of pic as the ancillary ligand results in blue-shifted emission, stabilization of the oxidation potential, and improvement of the photoluminescence quantum yield, and only minor differences in the optoelectronic properties are found between the two diastereoisomers of each pair.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Reversible electronic energy transfer is used for sensing oxygen traces and results in very high sensitivity.

A cyclometalated iridium complex is reported where the core complex comprises naphthylpyridine as the main ligand and the ancillary 2,2'-bipyridine ligand is attached to a pyrene unit by a short alkyl bridge. To obtain the complex with satisfactory purity, it was necessary to modify the standard synthesis (direct reaction of the ancillary ligand with the chloro-bridged iridium dimer) to a method harnessing an intermediate tetramethylheptanolate-based complex, which was subjected to acid-promoted removal of the ancillary ligand and subsequent complexation. The photophysical behavior of the bichromophoric complex and a model complex without the pendant pyrene were studied using steady-state and time-resolved spectroscopies. Reversible electronic energy transfer (REET) is demonstrated, uniquely with an emissive cyclometalated iridium center and an adjacent organic chromophore. After excited-state equilibration is established (5 ns) as a result of REET, extremely long luminescence lifetimes of up to 225 μs result, compared to 8.3 μs for the model complex, without diminishing the emission quantum yield. As a result, remarkably high oxygen sensitivity is observed in both solution and polymeric matrices.

A two-step process for the synthesis of trifluoromethyl-substituted cyclopropanes is described. Halothane, an anesthetic agent, is added to olefins in a ruthenium-catalyzed Kharasch reaction. The resulting 1,3-dihalides are converted into cyclopropanes by dehalogenation with magnesium. This procedure represents an alternative to metal-catalyzed cyclopropanations involving trifluoromethyl diazomethane.