Room temperature fast synthesis four-membered red iridium(III) complexes containing Ir–S–P–S structures for OLEDs

Detailed Molecular and Structural Analysis of Dual Emitter IrQ(ppy)2 Complex

The molecular structure of the 8-hydroxyquinoline–bis (2-phenylpyridyl) iridium (IrQ(ppy)₂) dual emitter organometallic compound is determined based on detailed 1D and 2D nuclear magnetic resonance (NMR), to identify metal-ligands coordination, isomerization and chemical yield of the desired compound. Meanwhile, the extended X-ray absorption fine structure (EXAFS) was used to determine the interatomic distances around the iridium ion. From the NMR results, this compound IrQ(ppy)₂ exhibits a trans isomerization with a distribution of coordinated N-atoms in a similar way to facial Ir(ppy)₃. The EXAFS measurements confirm the structural model of the IrQ(ppy)₂ compound where the oxygen atoms from the quinoline ligands induce the splitting of the next-nearest neighboring C in the second shell of the Ir³⁺ ions. The high-performance liquid chromatography (HPLC), as a part of the detailed molecular analysis, confirms the purity of the desired IrQ(ppy)₂ organometallic compound as being more than 95%, together with the progress of the chemical reactions towards the final compound. The theoretical model of the IrQ(ppy)₂, concerning the expected bond lengths, is compared with the structural model from the EXAFS and XRD measurements.