Study on microwave synthesis of platinum metal complexes and the dielectric property of their reaction media

摘要

Ru(II) and Ir(III) complexes are important functional materials with their phosphorescent properties. Ir(III) complexes are used as excellent dopants for OLED and Ru(II) complexes as good oxygen sensors. As these metals are rarely occurring in nature, and inert to chemical synthetic process. Conventional synthesis of these complexes have various difficulties such as long reaction time and lower yields. These metal complexes can be more quickly and easily synthesized with a higher yield under microwave irradiation than conventional conditions. It is desirable to apply this procedure for highly functional substances applied to commercially available needs. We have been studying the synthesis of these complexes with various microwave reactors. To clarify the physicochemical aspect of these microwave effects on the synthetic reaction, dielectric properties of each component of reaction solution are measured. The dielectric parameters for reaction solutions, including RuCl3 · 3H2O, IrCl3 · 3H2O, ethylene glycol as solvent are measured using network analyzer at various temperature and frequencies from 100 MHz to 20 GHz. The network analyzer of Agilent N5242A with 85070F soft wear was used. The semi-empirical Cole-Cole relaxation spectrum based on the Debye Eq. shows abrupt increase in the lower frequency range, showing the contribution of conductivity parameter (σ). Experimental data for dielectric parameters, ε", ε' and σ are reported. Molecular orbital aspect for reaction process, DFT calculation for microwave synthesis of Ir(ppy)3 was carried out and it gives valuable information on the stability of two isomers, facial and meridional Ir(ppy)3, and their dipole moments.