Synthesis of carbon dendron nano-chains with π-extended conjugation based on linear 1,4-phenylethynyl and 1,5-naphthylethynyl subunits

A convenient and efficient synthesis of 3,5-di(trimethylsilylethynyl)phenylacetylene and p-[3,5-di(trimethylsilylethynyl)-1-phenylethynyl]phenylacetylene and the naphthylethynyl homologues terminal acetylenes of 5-(N,N-dimethylamino)naphthylethyne have been carried out. These terminal acetylene compounds serve to prepare nanometer-sized conjugated 1,3,5-tri(ethynylphenyl)benzene and 1,3,5-tri(ethynylnaphthyl)benzene oligomers, by means of heterocoupling with 1,3,5-triiodobenzene, catalysed by palladium, in excellent yields. Both the ethynylphenyl or ethynylnaphthyl homologues chains show fluorescence emission radiation, with important quantum yield.