Catalytic Oxidation of 2,7-Dihydroxynaphthalene

Two polymer-metal complexes were used for catalytic oxidative polymerization of 2,7-dihydroxynaphthalene (DHN) with the aim of exploiting new and potent catalysts. The structure of the resulting poly(2,7-dihydroxynaphthalene) (PDHN) was confirmed by various spectral techniques: UV-vis, FT-IR, H-1 NMR, C-13 NMR, H-1-H-1 COSY, and H-1-C-13 HSQC. The 3 and 6 positions of the DHN ring were suggested as main coupling sites. The effect of the reaction conditions on the monomer conversions and the polymer molecular weight was determined: yields in the range 74-99% and number-average molecular weights in the range 1700-83 000 g mol(-1) were obtained. Thermal, optical, and electrochemical behaviors of the polymer were also studied. From fluorescence analyses, a case of negative solvatochromism for PDHN was established.