Synthesis and luminescence properties of polymer–rare earth complexes containing salicylaldehyde‐type bidentate Schiff base ligand

Abstract

Using molecular design and polymer reactions, two types of bidentate Schiff base ligands, salicylaldehyde-aniline (SAN) and salicylaldehyde-cyclohexylamine (SCA), were synchronously synthesized and bonded onto the side chain of polysulfone (PSF), giving two bidentate Schiff base ligand-functionalized PSFs, PSF-SAN and PSF-SCA, referred to as macromolecular ligands. Following coordination reactions between the macromolecular ligands and Eu(III) and Tb(III) ions (the reaction occurred between the bonded ligands SAN or SCA and the lanthanide ion), two series of luminescent polymer-rare earth complexes, PSF-SAN-Eu(III) and PSF-SCA-Tb(III), were obtained. The two macromolecular ligands were fully characterized by Fourier transform infrared (FTIR), H NMR and UV absorption spectroscopy, and the prepared complexes were also characterized by FTIR, UV absorption spectroscopy and thermo-gravity analysis. On this basis, the photoluminescence properties of these complexes and the relationships between their structure and luminescence were investigated in depth. The results show that the bonded bidentate Schiff base ligands, SAN and SCA, can effectively sensitize the fluorescence emission of Eu(III) and Tb(III) ions, respectively. PSF-SAN-Eu(III) series complexes, namely the binary complex PSF-(SAN) -Eu(III) and the ternary complex PSF-(SAN) -Eu(III)-(Phen) (Phen is the small-molecule ligand 1,10-phenanthroline), produce strong red luminescence, suggesting that the triplet state energy level of SAN is lower and well matched with the resonant energy level of the Eu(III) ion. By contrast, PSF-SAN-Eu(III) series complexes, namely the binary complex PSF-(SCA) -Tb(III) and the ternary complex PSF-(SCA) -Tb(III)-(Phen) , display strong green luminescence, suggesting that the triplet state energy level of SCA is higher and is well matched with the resonant energy level of Tb(III).

Construction of three types of lanthanide complexes based on 3,4‐dimethylbenzoic acid and 5,5′‐dimethyl‐2,2′‐bipyridine: Syntheses, Structures, Thermodynamic properties, Luminescence, and Bacteriostatic activities

“…In addition, the emission spectrum for complex 3 was monitored on the fixed excitation wavelength at 298 nm, and it exhibits five characteristic sharp emission peaks of Eu (III) ions at 578, 593, 613, 652 and 703 nm assigned to 5 D 0 → 7 F 0 , 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 and 5 D 0 → 7 F 4 transitions respectively. And the hypersensitive transition of 5 D 0 → 7 F 2 at 613 nm is the strongest and pure red emission spectrum …”

“…And the hypersensitive transition of 5 D 0 → 7 F 2 at 613 nm is the strongest and pure red emission spectrum. [25,26] The CIE chromaticity coordinates of complexes 2 and 3 are given in Figure 14. The emission data of complexes 2 and 3 were calculated by CIE diagram and marked by two black spots at (0.668, 0.298) and (0.641, 0.357) respectively.…”

Structure and Properties of PET Nano‐Porous Luminescence Fibers for Fluorescence‐Indicating to Acid Gases

“…To reveal the fluorescence‐indicating mechanism of PNPLFs to acid gases, the X‐ray diffraction (XRD) curves and FTIR spectra of PATC before and after adsorption of acid gas were tested and studied . Figure shows the XRD curves and FTIR spectra of PATC.…”

Heterometallic ZnII–LnIII–ZnII Schiff Base Complexes with Linear or Bent Conformation—Synthesis, Crystal Structures, Luminescent and Magnetic Characterization

“…The band with the greatest intensity at 229.0 nm is attributed to π-π* transition in the benzene ring. The weak peaks at 292.5 and 341.5 nm correspond to the π-π* transition of the phenol and C = N chromophore groups, whereas weak peak at 425.5 nm is ascribed to the n-π* electron transition in the ligand [ 43 , 44 , 45 ].…”