Preparation and Luminescence of Novel O-Phenanthroline-Acyl Amino Acid Rare Earth Praseodymium Complexes

Abstract

The o-phenanthroline-acyl-amino acid praseodymium complex (Pr [CH 3 (CH 2 ) 4 CO NHC H(CH 3 )COO] 3 ꞏphen) has been synthesized by an in-solution chemical reaction method using H(hex-ala) and 1,10-phenanthroline (phen) as ligands with a view to obtaining rare-earth organic complexes with good optical properties. The molecular structure of the praseodymium complex was determined using CHN elemental analysis, 13 C NMR testing, and FT-IR spectroscopic testing. We also perform wide-angle and small-angle XRD diffraction wave analysis, polarization microscopy observation, light absorption testing, fluorescence spectral analysis, fluorescence lifetime analysis, and fluorescence variable temperature spectral analysis. The results indicate that the introduction of the auxiliary ligand phen results in a periodic short-range ordered structure and better crystallinity of Pr (hex-ala) 3 ꞏphen, which exhibits strong optical anisotropy in the molten state. Good light absorption in the UV-visible region (200 nm - 420 nm), switching from ligand luminescence to a rare earth centered luminescence mechanism, and photoluminescence shifting from the blue to the green region. High fluorescence intensity in the visible and near-infrared regions, good fluorescence lifetime (0.76 µs), and good thermal stability in the range of 25 °C - 200 °C.