Grignard Metathesis Polymerization and Properties of 1,1-Disubstituted-2,5-dibromo-3,4-diphenylsiloles

Abstract

Grignard metathesis polymerizations of 1,1-disubstituted-2,5-dibromo-3,4-diphenylsiloles such as 1,1dimethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diethyl-2,5-dibromo-3,4-diphenylsilole, 1,1-diisopropyl-2,5-dibromo-3,4-diphenylsilole, and 1,1-dihexyl-2,5-dibromo-3,4-diphenylsilole were performed to yield poly(1,1disubstituted-3,4-diphenyl-2,5-silole)s containing fluorescent aromatic chromophore groups such as phenyl and silole in the polymer main chain: poly(1,1-dimethyl-3,4-diphenyl-2,5-silole), poly(1,1-diethyl-3,4diphenyl-2,5-silole), poly(1,1-diisopropyl-3,4-diphenyl-2,5-silole), and poly(1,1-dihexyl-3,4-diphenyl-2,5silole), respectively. The obtained materials are highly soluble in common organic solvents such as chloroform and tetrahydrofuran. Fourier-transform infrared spectra of all the polymers have characteristic C=C stretching frequencies at 1620-1628 cm. The prepared organosilicon polymers exhibit strong absorption maximum peaks at 273-293 nm in the tetrahydrofuran solution, showing a redshift of 18-34 nm relative to those of the monomer, strong excitation maximum peaks at 276-303 nm, and strong fluorescence emission maximum bands at 350-440 nm. Thermogravimetric analysis shows that most of the polymers are stable up to 200 C with a weight loss of 6-16% in nitrogen.