Synthesis, Characterization of the Luminescent Lanthanide Complexes with Copolymer of (Z)-4-oxo-4-phenyloxyl-2-butenoic Acid and Styrene

The copolymers of (Z)-4-oxo-4-phenoxyl-2-butenoic acid with styrene (PSt/OPBA) and their macromolecular luminous lanthanide complexes (Ln-PSt/OPBA) have been synthesized and characterized by means of GPC, elemental analysis, FTIR, X-ray powder diffraction, spectral analysis, and thermal analysis. The IR studies showed that the carboxylic groups on the side chain of the polymer were coordinated to lanthanide ions by bidentate manner. However, the ethereal oxygen, instead of carbonyl, also bonded to the central lanthanide ions, which was an intriguing phenomenon for ester-coordinated complexes. X-ray diffraction experiments revealed that these PSt/OPBA copolymers were amorphous, but Ln-PSt/OPBA were crystalline, in which the complex Eu-L-c belonged to a high symmetric structure of orthorhombic quadratic system, with a = 10.59 +/- 0.02 angstrom, c = 8.02 +/- 0.01 angstrom; c/a = 0.763. In addition, the value delta (the number of free carboxylic groups) in Ln-PSt/OPBA complexes increased with the decreasing mole ratio of styrene in the copolymers, while it decreased with increasing pH values of the solution. Eu3+ and Tb3+ complexes exhibited characteristic fluorescence with comparatively high brightness and good monochromaticity, and the fluorescence intensity was enhanced with increasing the content of lanthanide up to around 18 wt % without typical fluorescence concentration quenching behavior in the solid state. So using polymers as a matrix, Ln-PSt/OPBA are likely to provide new materials that possess specific properties and desired features. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2540-2547, 2012