Preparation of soluble poly(azomethine)s having the beta-diketonate metal complex in the main chain

Copper complexes (2a-Cu and 2b-Cu) having two amino groups were prepared fr om p-aminobenzoylacetone (1a) and 1-(4-aminophenyl)nonane-1,3-dione (1b) wi th copper(II) acetate, respectively. A soluble poly(azomethine) having beta -diketonato copper(II) complex in the main chain was prepared by the polyco ndensation of 2b-Cu with terephthalaldehyde (3) in dimethyl sulfoxide (DMSO ) at room temperature with H2SO4 as catalyst. After reprecipitation into me thanol, a green product was obtained in 56% yield. The complex (5b-Cu), was soluble In common organic solvents such as CHCl3, tetrahydrofuran (THF), a nd DMSO. The number-average molecular weight (M-n) and molecular weight dis tribution of 5b-Cu determined by GPC were M-n = 3500 (polystyrene standard) and M-w/M-n = 1.71, respectively. The structure of 5b-Cu was supported by IR and elemental analysis. Thermogravimetric analysis (TCA) for 5b-Cu showe d 5% weight loss at 250 degrees C under nitrogen. Electrochemical data as w ell as absorption spectra of Sb-Cu in comparison with that of copper(II) bi s[p-(1-aza-2-phenylethenyl)benzoylacetonate] (6) as a model compound show t hat the metal centers of the multinuclear complexes may be considered nearl y independent of one another.