Measurement and analysis of the temperature and pressure dependence of the 7F0→5D0 excitation spectra of Eu(III) complexes with 4-phenylethynyl-2,6-pyridine-dicarboxylic acid

Abstract The pressure and temperature dependence of the 5D0→7F0 transition of Eu(III) in complexes with 4-phenylethynyl-2,6-pyridinedicarboxylic acid has been measured at various metal to ligand ratios. The spectra have been fit to a sum of Lorentzian peaks, and the temperature dependence used to determine ΔH for the equilibrium reaction for formation of the tris complex from the bis complex. The pressure dependence of the 5D0→7F0 transitions corresponding to the bis and tris species is analyzed in order to determine the associated difference in volume, ΔV, between reactants and products.