Synthesis and photophysical characterization of the free-radical copolymerization of metal oquinolate-pendant monomers with methyl methacrylate

A series of novel metaloquinolate [aluminum quinolate (Alq(3)), zinc quinolate (Znq(2)), and lithium quinolate (Liq)]-containing copolymers were prepared. This is the first report of the synthesis of metaloquinolate-containing polymers by free-radical copolymerization. The structures of the metaloquinolate monomers and copolymers were characterized by H-1 NMR and Fourier transform infrared techniques. The differential scanning calorimetry and thermogravimetric analysis results showed that the copolymers were more thermally stable than the methyl methacrylate homopolymer. The copolymers (<25 wt % Alq(3), <20 wt % Znq(2), or <15 wt % Liq) could be dissolved in common solvents without crosslinking. The ultraviolet-visible absorption and photoluminescence (PL) emission properties of the copolymers were consistent with the literature data of metaloquinolate complexes. The PL efficiencies of the metaloquinolate-containing copolymers with 25 wt % Alq(3), 20 wt % Znq(2), or 15 wt % Liq were 19.89, 13.24, and 11.82%, respectively. The experimental results indicated that these kinds of materials could be used for practical applications in organic light-emitting diodes. (C) 2004 Wiley Periodicals, Inc.