Synthesis and luminescence properties of polymeric complexes of Cu(II), Zn(II) and Al(III) with 8-hydroxyquinoline side group-containing polysulfone

Three kinds of metaloquinolate-containing polysulfones were prepared via a polymer reaction and a coordination reaction. 5-Chloromethyl-8-hydroxyquinoline (CHQ) was first prepared through the chloromethylation reaction between 8-hydroxyquinoline (HQ) and chloromethylation reagent 1,4-bichloromethoxy-butane (BCMB). A polymer reaction, Friedel–Crafts alkylation reaction, was carried out between polysulfone (PSF) and CHQ in the presence of Lewis catalyst, and HQ was bonded onto the side chains of PSF, obtaining 8-hydroxyquinoline-functionalized PSF. And then, by using one-pot method with two-stage procedures, the coordination reaction of HQ-PSF and small molecule HQ with metal ions including Al (III), Zn(II) and Cu(II) ions, was allowed to be carried out, and three polymeric metaloquinolates, AlQ3-PSF, ZnQ2-PSF and CuQ2-PSF, were successfully prepared. In their chemical structures, metaloquinolates were chemically attached onto the side chains of PSF. HQ-PSF and three polymeric metaloquinolates were fully characterized by FTIR and 1H NMR. The luminescence properties of the three polymeric metaloquinolates were mainly investigated by UV/vis absorption spectra and fluorescence emission spectra in solutions and in solid film state. When excited by the ray at 370 nm, the three polymeric metaloquinolates emit blue/green lights, and the main emission peaks in the solutions are located at 508, 487 and 495 nm for AlQ3-PSF, ZnQ2-PSF and CuQ2-PSF, respectively. As compared with their emissions in solutions, the emissions in solid film state are red-shifted to some extent, and they are located at 518, 492 and 509 nm for AlQ3-PSF, ZnQ2-PSF and CuQ2-PSF, respectively.