Synthesis of platinum-containing poly(phenyleneethynylene)s having various chromophores: aggregation and optical properties

Abstract

The Sonogashira–Hagihara coupling polymerization of platinum-containing m,m-phenylene and p,p-phenylene-linked diethynyl monomers m,m-1 and p,p-1 with 1,4-dibromobenzene 2a, 1,4-dibromonaphthalene 2b and 9,10-dibromoanthracene 2c was carried out to obtain the corresponding platinum-containing polymers [poly(m,m-1-2a)–poly(m,m-1-2c)] and [poly(p,p-1-2a)–poly(p,p-1-2c)] with M_n's ranging from 4,300 to 28 000 in 24%-quantitative yields. The UV-vis absorption and emission properties of the formed polymers were measured in various solvents to examine the solvent effect on the optical properties. These polymers emitted fluorescence at 400–600 nm with 3.4–18.0% quantum yields in THF, CHCl₃ and CH₂Cl₂. The fluorescence intensities of the polymers remarkably decreased upon raising the MeOH concentration in THF/MeOH mixtures, accompanying the formation of aggregates.