Enhanced electrogenerated chemiluminescence of phenylethynylpyrene derivatives: use of weakly electron-donating group as a substituent.

A weakly donating group (n-propyl) has been used as a substituent at the para-position of the phenyl group for a series of phenylethynylpyrene derivatives where the number of phenylethynyl peripheral arms appended to the pyrene core is varied. This system markedly improved the concurrent stability of both cation and anion radicals and consequently greatly improved electrogenerated chemiluminescence (ECL). Density functional theory (DFT)-based theoretical calculations supported the associated photophysical and electrochemical properties of the series compounds.